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University Microfilms 300 North 2eeb Road Ann Arbor, Michigan 48106

A Xerox Education Company 73-2031

JOHNSON, Martin Wesley, 1941- CONSTRUCTION OF A TRUNK FLEXION STRENGTH- ENDURANCE TEST FOR COLLEGE MEN.

The Ohio State University, Ph.D., 1972 Education, physical

University Microfilms, A XEROX Company, Ann Arbor, Michigan

© Copyright by

Martin Wesley Johnson

1972

THIS DISSERTATION HAS BEEN MICROFILMED EXACTLY AS RECEIVED. CONSTRUCTION OF A TRUNK FLEXION STRENGTI1 -ENDURANCK

TEST FOR COLLEGE MEN

DISSERTATION

Presented in Partial FulTillment of the Requirements fo the Decree Doctor of Philosophy in the Graduate School of tho Ohio State University

By

Martin Wesley Johnson, B,S,, M .Ed *

*****

The Ohio State University 1972

Approved by PLEASE NOTE:

Some pages may have

indistinct print.

Filmed as received.

University Microfilms, A Xerox Education Company ACKNOWLEDGEMENTS

The writer wishes to express his appreciation to the

many persons who contributed to the successful completion of

this study. Special gratitude is expressed to my advisor

Dr. Seymour Kleinman, and to committee members, Dr, Edward

Fox and Dr. Robert Bartels, for ;heir guidance and as­

sistance in the conduct of this study. Special thanks are

also extended to the administration and students of the participating North Dakota colleges and universities for

their cooperation. The writer would also like to thank Dr.

Frederick Hagerman of Ohio University who indirectly provided

the original impetus for this study. Finally, the writer wishes to express gratitude to his wife for her under­

standing and encouragement throughout the course of this s tudy.

H VITA

November 27, 19^1 . • * Born - Georgetown, Minnesota

1960-1963 • • ...... United States Marine Corps

1966 . • * B.S. Mayville State College

1 9 6 6 -1 9 6 7 ...... Instructor of Health, Physical Edu­ cation, and Recreation, Mayville State College, Mayville, North Dakota

1 9 6 7 -1 9 6 8 ...... Teaching Assistant, Physical Edu­ cation Department, University of Arizona, Tucson, Arizona

1 9 6 8 ...... M. Ed., University of Arizona

1 9 6 8 - 1 9 6 9 ••••••• Physical Education Teacher and Coach, Morenci, Arizona, High School

1969-1971 ...... • Recreation Director, Wyandotte Communities, Columbus, Ohio

1971-1972 ...... • Assistant Professor of Education, Mayville State College, Mayville, North Dakota

FIELDS OF STUDY

Major Field: Physical Education

Minor.Field: Health Education

ill TABLE OF CONTENTS

Page

ACKNOWLEDGMENTS ...... ii

VITA ...... iii

LIST OF T A B L E S ...... vii

Chapter

I. INTRODUCTION...... 1

Statement of* the Problem Hypothesis Assumptions and Limitations Definitions

II. REVIEW OF RELATED LITERATURE...... 10

Validity of the Sit-up as a Tost of Abdominal Muscle Strength Position of the Legs During the Sit-up Test Potential Hazards of Sit-ups Electromyographic Research on Muscle Action During the Sit-up and Similar Movements Importance of Maintaining Strong Abdominal Muscles Summary

III. METHODS AND PROCEDURES...... 31

Phase I - Test Selection

Description of the Subjects Experimental Test Apparatus

Background Apparatus Specifications

Administration of the Experimental Tests

Experimental Test - Variation I Experimental Test - Variation II TABLE OF CONTENTS— Continued

Chapter Page

Experimental Test - Variation III Administration of the Static Trunk Flexion Strength Test Instrument Reliability of Procedures Method Administration of the Dynamic Trunk Flexion Strength Test Instrument Reliability of Procedures Method Testing Procedure - Phase I Phase II - Validation of the Proposed Test Description of the Subjects Methods Employed in the Validation of the Proposed Test Methods Employed in Determining- the Bases for Norms Weight Standing Height Sitting Height

Statistical Analysis Testing Procedure - Phase II

Phase III - Construction of Norms

Description of the Subjects Method of Norm Construction

Hull Scale

IV. ANALYSIS OF THE D A T A ...... 52 Phase I

Statistical Analysis Criterion Test Reliability Selection of the Proposed Test Discussion - Phase I

v TABLE OP CONTENTS— Continued Chapter Page Anthropometric Measurements Experimental Test Reliability Criterion Strength Test for Phase II Experimental Test-Variation I Revisions

Phase II

Statistical Analysis Validity and Reliability of the Proposed Test Influence of Anthropometric Measures on Test Results Selection of a Time Limit for Admin­ istration of the Proposed Trunk Flexion Strength-Endurance Test

Phase III

Norm Tables Hull Scale Norm Table Descriptive Norm Table

V. SUMMARY, CONCLUSIONS, AND RECOMMENDATIONS . . 75

Summary Procedure Reliability and Validity of the Proposed Test The Proposed Trunk Flexion Strength- Endurance Test Conclusions Relationship of the Findings to the Stated Hypotheses Re c ommendat ions

APPENDIX

A. QUESTIONNAIRE 85 B. PHOTOGRAPHS OF EXPERIMENTAL EQUIPMENT .... 87

C. TEST APPARATUS DIMENSIONS 104

BIBLIOGRAPHY 106

vi LIST OF TABLES Table Page 1. QUESTIONNAIRE DATA - PHASE I SUBJECTS , . , . . 33 2. PHASE I - TESTING SCHEDULE ...... 43 3. QUESTIONNAIRE DATA - PHASE II SUBJECTS .... 45 4. PHASE II - SCHEDULE OF TESTING AND NUMBER TESTED EACH P E R I O D ...... 49 5. DISTRIBUTION OF SUBJECTS UTILIZED IN THE CONSTRUCTION OF NORMS ...... 50 6 . PHASE I - DESCRIPTIVE STATISTICS ...... 54 7. SUMMARY OF DATA ON CRITERION TEST RELIABILITY . 55 8 . PHASE I - INTERCORRELATIONS...... 57 9. COMPARISON OF MEANS BETWEEN VARIATION I AND VARIATION I I ...... 58 10. COMPARISON OF CORRELATIONS WITH THE STATIC TRUNK FLEXION STRENGTH TEST AS THE COMMON VARIABLE ...... 60 11. COMPARISON OF CORRELATIONS WITH THE DYNAMIC TRUNK FLEXION STRENGTH TEST AS THE COMMON VARIABLE ...... 61

12. PHASE II - DESCRIPTIVE STATISTICS ...... 65

13. INTERCORRELATIONS FOR PHASE II VARIABLES . . . 65 14. SUMMARY OF DATA ON TEST VALIDITY ...... 6 6 15. SUMMARY OF DATA -ON TEST RELIABILITY...... 6 8 16. DESCRIPTIVE STATISTICS OF THE PROPOSED TEST SCORES AT TEN-SECOND INTERVALS (N = 80) . . . . 6 9 17. THE PROPOSED TRUNK FLEXION STRENGTH-ENDURANCE TEST HULL SCALE NORM TABLE FOR COLLEGE MEN . . 73

18. THE PROPOSED TRUNK FLEXION STRENGTH-ENDURANCE TEST DESCRIPTIVE SCALE NORM TABLE FOR COLLEGE MEN ...... 74

vil CHAPTER I

INTRODUCTION

The pendulum of interest in physical fitness in

general, and fitness tests in particular has swung back and

forth over the years. The present emphasis began in the

1950*s when the results of the Kraus-Weber minimal muscular

fitness tests, given to thousands of children, emphasized 7 the need for more vigorous physical education programs. As

a result, more people are involved in both organized and un­

organized exercise programs than ever before in the history 2 of the United States. The Kraus-Weber test was followed by

a battery of new and more extensive "physical fitness" tests,

the most widely used of these being the American Association

for Health, Physical Education, and Recreation Youth Fitness

Test.10 Since 1958, when the AAHPER Youth Fitness Test was

first published, it has been administered to millions of

children throughout the World.1-

One of the more popular exercises in many fitness

programs and tests is the sit-up, which has long been used both to strengthen the abdominal muscles and to test the

performance of these muscles. Traditionally, the exercise

is performed in the supine position with the legs extended, 2 and usually the feet are restrained while the trunk is raised against gravity.

In the past, knowledge of muscle function and con­ traction was established largely through palpation and by a mechanical analysis of the muscle's attachments and fiber direction. Modern researchers have at their disposal a number of sensitive scientific tools to aid them in accurate­ ly identifying muscle function. With the advent of improved methods, including electromyography, the conclusions reached by the early researchers in anatomy and kinesiology were re­ examined. The majority have proved valid, but a number of misconceptions have been disclosed. One such misconception was the suggestion that the musculature of the abdominal wall functioned during thigh flexion regardless of pelvic position.

Electromyography has revealed that thigh flexion activates the muscles of the abdominal group only during posterior tilt of the pelvis."*0

Just as muscle function, as defined by the older methods, was subject to error, so was the assumption that certain kinds of physical exercise would produce desired results. A number of large muscle exercises have been used by physical educators and physical therapists to develop strength and fitness with the suitability of these exercises being justified on the basis of palpation and mechanical analysis. As a result, the rationale for certain exercises is unfounded. This is particularly true of the sit-up. Not until the intensive electromyographic studies by Walters and Partridge,^ Sheffield,and Flint and Gudgell2** was the sit-up, unless performed with a posterior tilt of the pel­ vis, shown to be a major strengthener of the hip flexors rather than the muscles of the abdominal group.

Many authorities 22* ^now feel that sit-ups performed from the longlying position actually may be detrimental to the lumbar area by development of the hip flexor muscles (iliopsoas) without a corresponding develop­ ment of the abdominal muscles.

According to Michele 51 the iliopsoas, in order to maintain the normal lumbar curve and stabilize the erect posture, is one of the most powerful muscles of the body.

The maintenance of the normal lumbar curve is a function not only of the iliopsoas but also the antagonist muscles of the abdominal group. 2 Allsop states that "any development of the ilio­ psoas muscle must be accompanied by a concurrent develop­ ment of the abdominal muscles to maintain a balance and the normal lumbar curve." It is contended that many common daily activities such as walking, running, and climbing stairs are effective in developing the iliopsoas muscles.

However, most of these activities are not effective in de­ veloping the antagonist abdominal and gluteal muscles.

Therefore, specific exercises are needed to develop the ab­ dominal muscles with minimum activity of the iliopsoas muscle.2

Mathews is of the opinion that there is very little reason for including the longlying sit-up in physi­

cal fitness programs for strengthening the abdominal mus­

cles because the primary muscle involved in the movement 4 9 may be the iliopsoas. Mathevs stated, "the iliopsoas muscle usually appears to be well developed in even the most emaciated cadavers; further confirmation of the theory

that the most efficient exercises for strengthening the ab­

dominal muscles should leave the iliopsoas as nearly inac­

tive as possible."

Physical educators engaged in the construction and validation of tests are frequently confronted by the query,

"What does this test measure?" Since the advent of measure sent in physical education, physical educators have endeav­

ored to ascertain accurately physical fitness. As a result a number of tests of physical fitness, most of which con­

tain some test of abdominal strength, have been developed.

The most common test of abdominal strength used is the sit- up, which imperfectly measures abdominal strength. 20 If an accurate picture of an individual's total physical fitness is to be obtained each item must be tested in the most val­

id method possible. "The manner in which most of these ab­ dominal strength tests are conducted permits weakness of these muscles to go undetected."^

There has been considerable research conducted on

the validity of, and administration techniques for abdo­ minal strength tests of the sit-up variety. However, re­ search conducted indicates a lack of validity for the sit- 5 up as a test of abdominal muscle strength; administered

from either the hooklying or longlying position, with or

without a specific time limit* In addition, a number of

researchers have expressed concern over the sit-up as con­

ducted in most fitness tests as a possible contributing

factor in low back pain.

Research leading to the development of a valid

strength-endurance test primarily for muscles of the abdom­

inal group is needed. This test should not require expensive

or elaborate equipment, and should in no way be detrimental

or hazardous to one's health if used as an exercise.

In light of this information, the writer was led to

initiate a study to seek an alternative abdominal exercise

and strength-endurance test to the traditional sit-up. The

test design would be based upon the findings disclosed in

recent electromyographic and other research studies of the

iliopsoas and abdominal muscles.

Statement of the Problem

The primary concern of this study was to develop a valid and reliable strength-endurance test, of the sit-up variety, for the abdominals, in which the pelvis is stabi­

lized and hip flexor action is reduced to a minimum. A

second aspect of this study was the establishment of the banes of norms for the proposed trunk flexion strength-

endurance test through study of a select number of anthro- pometric measures, A final aspect of this study was to construct norms for the proposed test for use by college age males.

Hypothesis

It was hypothesized that trunk flexions performed in the supine position, with the subjects hips flexed and pelvis secured in the posterior tilt position would be a valid and reliable strength-endurance test for muscles of the abdominal group. Also, it was hypothesized that the anthropometric measures; height, sitting height, and weight, would be insignificant factors in the subjects' performance of the proposed test.

Assumptions and Limitations

1, No remuneration of any kind was given the sub­ jects so it was assumed all were equally motivated to give their best performances on all tests administered.

2, The criterion measures for trunk flexion strength were limited to the cable tensiometer trunk flexion strength test for isometric or static strength, and a one- repetition with maximum load sit-up for isotonic or dynamic strength. The weights used in the one-repetition maximum sit-up were of varying circumference, therefore causing a slight variation in the type of grip employed by the sub­ jects. Also, the weights used were at minimum in two pound increments and thereby limited the discriminating power of this measure. 7 3* The selection of the subjects for all phases of

this study was limited to colleges and universities of

North Dakota.

Definitions

Strength. The force a muscle group can exert

against a resistance in one maximal effort. Xt is measured

in units of pounds or kilograms using dynamometers, tensi-

ometers, or manuometers,^ Strength endurance. The ability to sustain a mus­

cular force. This ability is significantly correlated with

the strength of a brief maximum effort. 52

Muscular endurance. The ability of a muscle group

to perform repeated contractions against a light load for 50 an extended period of time.

Abdominals or Abdominal Group. Muscle group con­

sisting of the Rectus Abdominis, External Oblique, and

Internal Oblique muscles, which in common produce spinal

flexion.^

Iliopsoas. "A single muscle is not solely respon­ sible for a single motion component. The individual muscle

is augmented by other related muscles and in turn, augments

the active components of related muscles.... The psoas major muscle is related topographically and functionally with the psoas minor and iliacus. This relationship is so close that they are commonly referred to as the iliopsoas group."..38 8

Trunk Flexion. The muscles of the thoracic and

lumbar spines involved in forward flexion of the trunk are

the abdominal group as the prime mover and the psoas as the

assistant mover. The muscles of the cervical spine involved

are the sternocleidomastoid as the prime mover, and the three

scaleni and the prevertabral group (longus colli, longus

capitis, rectus capitis anterior, rectus capitis lateralis) 58 as the assistant movers.

Static Trunk Flexion Strength. The muscles of the

abdominal group and anterior trunk effecting maximum force

in forward flexion of the trunk as measured by a cable

tensiometer will be referred to as static trunk flexion

strength.^

Dynamic Trunk Flexion Strength. The maximum weight that can be lifted by the muscles of the abdominal group and

anterior trunk in executing one sit-up will be referred to as

dynamic trunk flexion strength. Barbell plates of various

weights were used in determining the dynamic strength measure.19

Traditional Sit-up. Subject supine in the longlying position, places his hands behind his head, raises his head

and shoulders in an arc from the floor to a point where the

elbows come in contact with his knees. The score is the

total number of repetitions completed in a specified time limit. Longlying position, Sit-up starting position in which the subject is supine with legs extended,

Hooklying position, Sit-up starting position in which the subject is supine with legs flexed at the knee such that the upper leg and lower leg form approximately ninety degree angle at the knee joint. CHAPTER II

REVIEW OF RELATED LITERATURE

The sit-up has been an extremely controversial test

item in fitness tests for many years. With the advent of

World War II and an increased concern for accurate ap­ praisal of physical fitness, the sit-up became the object of many studies. The majority of these studies were con­ cerned with the technique of administration, the emphasis being- on the duration of the test. Most studies also at­ tempted to determine the validity of the sit-up as a test of abdominal strength and endurance.

In the 1950*3, research on the sit-up test was conducted utilizing more sophisticated methods of research, such as electromyography and the cable tensiometer.

However, the validity of the sit-up, conducted in the manner prescribed by most fitness tests, as a test of ab­ dominal muscular strength is still very questionable.

The literature reviewed and presented in this chap­ ter has been divided into five sections. These sections are as follows: validity of the sit-up as a test of abdo­ minal muscle strength; position of the legs during the sit- up test; potential hazards of sit-ups; electromyographic

10 11 research on muscle action during the sit-up and similar movements; and the importance of maintaining strong abdo­ minal muscles*

Validity of the Sit-up as a Test of Abdominal Muscle Strength 5 Bender and Shea state that there are two types of sit-up tests that are used most commonly and both need to be corrected. These tests are: (l) the sit-up from the longlying position with the feet secured, and the arms fully extended behind the head; (2) from the same position with the hands behind the head and the elbows winged out to the side. Both of these sit-ups can be accomplished by throwing the arms forward. For this reason, neither of these sit-ups test abdominal muscle strength because the body is moved by momentum produced by the speed of the arm movement and also by action of the hip flexor muscles. Rasch and Krauer 59 in a recent investigation con­ cluded that "the two-minute sit-up test does not measure the strength of the abdominal muscles and hip flexors to a significant degree." They further stated that "the two- minute sit-up appears to be primarily a measure of trunk flexion speed and secondarily a measure of the endurance of the abdominal muscles and hip flexors."

Berger^ evaluated the two-minute sit-up test as a measure of abdominal muscular endurance and strength in an attempt to determine if this test was related sufficiently to the sit-up test of no time limit. In his study he 12 administered three sit-up tests to forty-seven male college students. These tests were the two-minute sit-up test, sit-ups performed at the rate of twenty per-minute with no time limit, and one sit-up with maximum load. The criter­ ion for endurance was the twenty sit-ups per-minute and the strength criterion was the one sit-up with maximum load.

All sit-ups were performed with the knees flexed at a ninety degree angle, feet secured to the floor, and the hands were clasped behind the neck. The correlations ob­ tained were as follows:

Endurance - Two-minute to the twenty per-minute sit-up « 0.712 positive.

Strength - One repetition maximum to two-minute sit-up = 0.508 positive.

- One repetition maximum to twenty per- minute sit-up = 0.518 positive. g From Berger^ study it appears that both the two- minute sit-up and the sit-up test performed at the rate of twenty repetitions per-minute for no time limit are pri­ marily tests of muscular endurance rather than strength.

Kent State University employs a curl-down test as a measure of abdominal strength for women. The curl-down differs from the sit-up in that the subject is seated with knees flexed and feet flat on the mat. The hands are clasped behind the head with the chin tucked in and the elbows touching the knees. With a partner stabilizing the feet, the subject performs an eccentric contraction only until the shoulders touch the mat, and then returns im­ 13 mediately to the starting position* The score consists of the maximum number completed in thirty seconds* An in­ vestigation of the curl-down was conduoted using the scores the subjects obtained on an Elgin Multiple Angle testing unit as a criterion. The correlation coefficient obtained 28 for sixty subjects was a positive 0.1*4.

During World War IX and into the early 1950's* the sit-up as a test of abdominal strength and endurance was questioned frequently as to its validity. Many studies were initiated during this period to determine the method of conducting the sit-up test so that it could be con­ sidered a valid test of abdominal strength. The results of most of these studies proved insignificant*

In 1944* R. T, DeWitt^ conducted a study to test the validity of the sit-up as a test of strength and en­ durance. DeWitt's criterion for endurance consisted of an isometric hold executed with the back straight; the score was the number of seconds the subject could hold the po­ sition, The criterion for strength was a dynamometer score.

Three tests were given: feet not held* no time limit; feet held* no time limit; feet held* two-minute time limit. The results indicated that the correlation between the ability to perform tests of the sit-up type and abdominal strength and endurance is relatively low. It was concluded that size appears to bear little relationship to strength and endurance of abdominal muscles as measured in this study* and strength and endurance do not appear to be signifi- 14 caxitly related so far as the abdominal muscles are con­ cerned, Heavier and taller men appear to be handicapped in performing tests of the sit-up type, 68 Wedemeyer in 1946, used as a criterion for strength the Martin breaking strength method, and obtained a correlation of 0,45 positive to the two-minute sit-up, Johnson, 33 using the cable tensiometer trunk flexion test as the abdominal strength criterion also obtained a 0,45 positive correlation for the two-minute sit-up,

Cousins 14 reported that sit-ups, according to available literature, are more indicative of the strength of the thigh and hip flexor muscles than of the abdominal muscles. He was of the opinion that abdominal muscles do come into action to some extent in the correct performance of sit-ups; however, they are not the principal muscles involved. He concluded that some other test(s) must be employed to measure more adequately abdominal muscular strength. 29 i i Havlicek in 1944, investigated the sit-up test to determine the optimum duration. He concluded that the three minute test is the most accurate of those tested

(one, two, three and five-minute durations were tested) and that it is a more valid test of strength than the con­ tinuous sit-up test. How he determined this, or what criterion he used was not stated in the article. In his conclusions, he simply stated that the tests of one and 15 two-minute durations were not long enough; the subjects still had a ”lot left” at the completion of the time* Five minutes was too long, the subjects would simply pace them­ selves and they too would have some left when the time was up. But, the three-minute test "seemed to be the most accurate" because here the subjects would try and go all out * 3 4 Karpovich reported that the correlation between the number of longlying sit-ups which can be done in three minutes and those which can be done in an unlimited time is

0.54. Karpovich considered this too low to justify sub­ stituting the former for the latter in individual testing.

Correlations for one, two, four, and five minutes were even lower, with a 0.1*3 reported for the two-rainute sit-up test.

Rasch and Krauer 59 in a report they prepared for the Marine Corps on the two-minute sit-up, surmised that since a few individuals are able to accomplish very high repetitions in an untimed sit-up test and thus delay an entire testing program, a time limit becomes an adminis­ trative necessity.

Probably, the final adoption of the two-minute sit- up test came about in the manner and for the reason stated 65 by Vaglow; "a conclusion was reached to use the two- minute sit-ups, based mainly on empirical judgement using tt the criteria of administrability, particularly time. 16 Position of the Legs During the Sit-Up Test

The sit-up is the most common means used in testing the strength of the abdominal muscles; however, the proce­ dure used varies greatly from test to test* One of the major controversies in the administration of the sit-up test is the position of the legs. 2 Allsop found upon examination of twenty commonly used physical fitness tests that seventeen of the twenty, including the tests of the American Association for Health,

Physical Education, and Recreation (AAHPER) and the Pres­ ident's Council on Physical Fitness and Sports, required the sit-up to be performed from the longlying position.

Only three tests, the Baltimore City Elementary, the WAC

Physical Fitness Test for Girl3, and the California Phys­ ical Performance Test, require the sit-up to be performed from the hooklying position.

Kendall, in a similar examination reported that out of eighteen physical fitness tests, all included sit- ups, but in fifteen of the tests the legs were straight, and, out of this group of fifteen, on one of the tests the feet wore not held and on fourteen the feet were held.

Four of the tests used the bent knee position for sit-ups, and the feet were held on two of these. One test, the

Kraus-Weber, contained both legs straight and knees bent sit-ups• grt Soderberg stated that it has been proven that it 17 is more beneficial to perform the hooklying sit-up than the longlying sit-up. His justification for this statement was that when a person is performing a longlying sit-up the hip flexors become tight or contract to aid the performer dur­ ing the early stages of the exercise. Consequently, this movement allows one to perform a sit-up free of abdominal muscle activity and subjects the back to undesirable tension. However, in the hooklying position the hip flex­ or muscles have now been placed on a partial slack, and by producing hip flexion the pelvis is tilted upwards, thus forcing the lumbar spine into flexion and into contact with the supporting surface. In this position it is more diffi­ cult for the hip flexors to take the place of the abdom­ inals in the initial stage of the sit-up.

Not all sources totally concur with this analysis, n ^ Kendall postulates that in hooklying sit-ups the involve­ ment of the hip flexors is in no way eliminated. The dif­ ference in muscle action between longlying and hooklying sit-ups is simply that the hip flexors operate through a different arc of motion. The value of the hooklying position is that it prevents the back from arching during the sit-up. According to Kendall it is a widespread misconception that the action of the hip flexor muscles is eliminated or minimized by the bent knee position. She bases this statement on two factors: First, hip flexor action cannot be eliminated or there would be no sit-up 18 beyond initial trunk flexion; second, the principle that the action of a muscle can be eliminated or greatly mini­ mized by relaxing or shortening it as fully as possible applies to a two-joint muscle, but not to a one joint muscle. The iliopsoas is a one-Joint muscle. Tensor fascia latae and the rectus femoris muscle, which flex the hip and extend the knee, have about equal advantage with knees and hips extended as when knees and hips are flexed; the reason for this is that in each instance these muscles are elongated over one-joint while shortened over the other. To minimize the effectiveness of the tensor fascia latae and rectus femoris muscle, during the sit-up, the knee would have to be extended while the hips are flexed.

Kendall postulated that with knees bent, the tension on the iliopsoas and sartorius muscles is released and the pelvis can tilt posteriorly to allow more rounding of the lower back than when the knees are extended; and that is what led to the mistaken idea that there is more abdominal action and less hip flexor action in the sit-up when the knees are bent. However, the second phase of the sit-up is still entirely dependent on the action of the hip flexor muscles.

Valters and Harris^ in their investigation of an apparatus for moasuring abdominal muscle strength, stated that when sit-ups are performed with legs straight, the pivots are primarily at the hip joint, the sacroiliac 19

joints, and the lumbar vertebrate* This results in the

Immediate use of the hip flexor muscles and unless the upper spine is flexed throughout the movement, the abdom­

inal muscles work very little* 66 Walters and Harris also stated that the more acute or smaller the angle at the knee joint, the less

tension there is on the iliopsoas and thus the smaller the possibility of its being used very early in the sit-up*

From this study it was postulated that the trunk curl

performed against resistance was an effective test of ab­

dominal muscle strength and endurance. 6 7 Walters and Partridge in an electromyographic

study of the abdominal muscles discovered that there is

less activity of the hip flexors when the legs are flexed at a sixty-five degree rather than a ninety degree angle*

Also they stated that when the action of the hip flexors is minimized more power is needed by the abdominal muscles to perform the sit-up movement. 43 LaBan and others in an electromyographic study of

the iliopsoas muscle came up with some contradictory find­

ings. Their study of the iliopsoas muscle revealed activ­ ity during sit-ups only after the first thirty degrees from the legs extended position and through the entire range in

the hooklying position. They conclude that even though

this is true, common clinical opinion accepts the hooklying position for testing the strength of the abdominal muscles* 20

This is because with the hip flexed the iliopsoas is

shortened and therefore operates at a mechanical disad­

vantage . 43 From the above study it was found that the rectus

femoris indicated activity during the entire movement of

sit-ups regardless of position* This probably verifies the

notion that the abdominal muscles initiate the first thirty

degrees of the sit-up with the rectus femoris acting as a

pelvic stabilizer.

Rasch and Krauer 59 have reported that the corre­

lation between the two-minute longlying and the two-minute

hooklying sit-up test is only moderate (r » 0,54); and that

the correlation between the untimed longlying sit-ups and

the untimed hooklying sit-ups is even lower. They conclude

that this correlation reflects the differing roles the ab­

dominal and iliopsoas muscles play in these exercises.

All the literature consulted agreed that when the feet are held there is more activity in the hip flexorst

and that for those individuals with strong abdominals this

is not a factor, but for those with weak abdominal muscles holding the feet down can obscure weakness.

Potential Hazards of Sit -tips

Closely related to the issue regarding the position

of the legs during the sit-up movement, is the Issue con­

cerning muscle balance between hip flexor muscles (ilio­

psoas) and the abdominal muscles as a factor in low back 21 .. 3, 21, 31, 39. 41, 46, 53 problems. * A common criticism of* tho sit-up performed from the longlying position is that it may actually be detri­ mental to the lumbar area by development of the hip flexor muscles without a corresponding development of the abdom- inalJ , muscles. , 4,f 15. f 22, f 47, ’ 54 6*1 Soderberg stated that in his experience the hip flexors can be instrumental in performing a full sit-up, particularly when the subject is allowed to do the exercise from the longlying position. He further stated, "Anatom­ ical facts and clinical findings support the conclusion that abdominal strength should NOT be tested by the entire sit-up maneuver, and particularly not with the legs straight."

Nitsch 55 lends support to Soderberg*s statement concerning the full sit-up. She found in her study that a half curl-up with bent knees was as effective as the full curl-up with bent knees for increasing the strength of the abdominal muscles.

Performing the sit-ups with the legs held straight or bent with the lower back straight or concavely arched to any degree constitutes a hip flexor exercise and causes the abdomen to protrude. This exercise performed in the wrong manner produces tight hip flexor muscles and a protruding abdomen. Tight hip flexor muscles definitely contribute to the development of poor posture, and are also usually the 22 5 cause of groin injuries among physically active persons.

The relationship between poor posture and low back

pain, which has developed into a major health problem, is 9 well documented. A major cause of poor posture is

thought to be strength imbalance of the abdominal muscles 22 and the hip flexor muscles. * * Many afflicted with

lower back pain exhibit an exaggerated lumbar curve while

others show a marked lordosis. In these individuals, the pelvis is anteriorly tilted, and the iliopsoas muscle is in

a shortened position. A number of researchers have doc­

umented the secondary effects of an extreme lordosis as ex­

emplified by aching throughout the lower part of the back,

protrusion of the abdomen, generalized fatigue and eventual 2 degeneration of one or more lumbar discs. 47 Steidler expressed to Lowman and Young the

following opinion with regard to the sit-up performed from

either the longlying position or from a low bench with feet under a stall bar, as a method of developing the abdominals

and as a means of testing the strength of the abdominal muscles:

In order to do this the abdominal mus­ culature has to contract, but only on the basis of fixation. The actual work is being done by the psoas.

A high percentage of individuals have either a normal lumbar curve or an exaggeration of it up to a lordosis, in which case the pelvis is in a position of flexion in relation to the leg. Consequently the psoas, adductor longus, sartorius and tensor fascia are all in a short­ ened position. Why one should wish to develop 23 them to shorten them still further is hard to understand* 1 will agree that if you have strong enough abdominal muscles to keep your back flattened while you do these exercises, you may develop both abdominals and psoas but if the majority of individuals examined have a forward inclination of the pelvis then it would seem to me that it is not a good exercise*

J would say that these exercises are harmful and should be discontinued*,* * 8 ^9 Broer and Mathews concur that when the sit-up is performed from the longlying position the psoas muscles are put on stretch, and are therefore in excellent position to assist the abdominal muscles in the sit-up. The hooklying position releases the stretch of the psoas muscles and it cannot assist as strongly. The significance of this is that the psoas and iliacus muscles have some attachments on the lumbar vertebrae and therefore, any strong pull by these muscles with the legs secured could strain the low back, especially if the back is concavely arched during the movement. 18 Fahrni, in an article discussing the damaging effects of forward, backward and sideway bending exercises on the spinal disc, stated that sit-ups and raising the straight legs have a similar mechanism but are a little less damaging to the discs.

Electromyographic Research on Muscle Action During the Sit-Up and Similar Movements

Lipetz and Gutin hk conducted an electromyographic study to determine the intensity and duration of muscle action potentials in the upper and lover segments of the rectus abdominis muscle during four abdominal exercises: the conventional sit-up, the hooklying sit-up, the arched back sit-up, and the double leg raise. Results indicated that all three types of sit-ups had a significantly greater intensity of contraction than the leg lift exercise in both the upper and lower rectus abdominis. The three sit-up exercises did not differ significantly from each other. In duration, the arched back sit-up significantly surpassed the hook and conventional sit-up for both the upper and lover rectus abdominis muscle; the hook and conventional sit-up were not significantly different. It was also noted that

"in every subject, for both intensity and duration, the readings were much higher in the upper rectus than in the lower rectus."

A recent study by Flint and Gudgell^ indicated that of seventeen exercises studied the V-sit, basket hang, controlled backward lean, and curl-up produced the strong­ est action potentials vithin the abdominal musculature. 27 Gutin and Lipetz studied the upper and lower rec­ tus abdominis electrorayographically in ten strenuous abdom­ inal exercises and a trunk flexion isometric strength test.

Results of the study indicated that intensity of con­ traction was greatest in the basket hang, followed by three variations of the hooklying sit-up. The curl-up and the inclined, arched back and conventional sit-ups came next in 25 intensity, while the V-sit and controlled backward lean were the least strenuous exercises. These findings concur with those reported by Flint and Gudgell 23 for the basket 67 hang, but together with Walters and Partridge conflict 27 with the findings for the V-sit. Gutin and Lipetz also note that the basket hang, which is performed by suspending the body from a horizontal bar with knees flexed and body curled backward, is primarily a movement of thigh rather than trunk flexion. They suggest that the apparently stren­ uous nature of this exercise may be useful in the abdominal training of highly conditioned athletes.

Floyd and Silver, 2k through the use of a paired electrode grid, made an extensive study of the abdominal wall. To the rectus abdominis they attributed powerful activity during head raising in the supine position, but they also noted overall activity in the abdominal wall during lateral leg raising. The internal and external obliques were both found to be active when the subject strained with the breath held; only the internal oblique showed activity during relaxed standing. Results reported 62 by Sheffield agreed. 57 Partridge and Walters in their study of the par­ ticipation of the abdominal muscles in various movements of the trunk came up with the following findings: If the sit- up is performed without the twist phase all portions of the external obliques and rectus abdominis cease firing when 26

the trunk reaches ninety degrees. The trunk curl is just

as effective as full sit-ups in terms of motor unit re­

cruitment. Double leg raising is a strenuous task but con­

tributes little to strengthening of the abdominal muscles.

Finally, all portions of the external obliques and rectus

abdominis are activated best by a lateral bend of the

trunk, pelvic tilt, straight trunk curl and a trunk curl with rotation,

Valters and Partridge^ in another electromyo­ graphic study arrived at the following findings on the participation of the upper and lower rectus abdominis:

Exercise Muscle Participating Greatest

Sit-up Feet held Upper Feet not held Lower

*'V" sit-up Lower Reverse Trunk Curl Lower Trunk Curl Against resistance Equal No resistance Upper Sit-up with twist Upper Double leg lift Upper

It was found that the "V" sit created the greatest activity in both upper and lower rectus abdominis as well as the ex­ ternal obliques. The trunk curl was the next best for ac­ tivating all muscles at one time. From this study^ it was concluded that the sit-up, and its modifications and vari­ ations in the trunk curl and the ,fVn sit-up, is one of the most effective exercises for all abdominal muscles.

lf .8 MacConaill and Basinajian concur with other 27

researchers that the upper and lower abdominis vary in

response to different movements. They conclude that most

of the activity in the recti during trunk flexion from the

supine position occurs during the first half of the move­

ment , and trunk raising elicits more activity than trunk

lowering.

Importance of Maintaining Strong Abdominal Muscles

The strong association between weak abdominal

muscles and low back pain is quite well documented through-

out the literature. Kendall and others 37 noted that cases

of low back pain in which there is no tightness of the low

back muscles, but in which alignment is very faulty are

more common among women than men* "The fault is often

associated with weakness of the abdominal muscles*"

Kraus Uo commenting further on the low back problem

in women indicated the onset of backache during or after pregnancy is frequent and, more often than not, traceable

to a weak abdominal wall. 3 Alston and others in a study of the chronic low back syndrome stated that "weakness due to disuse may be a significant factor in the chronic low back syndrome even though initially the syndrome was caused by muscle strain, disc disease or some other organic disorder. The persist­ ence of low back symptoms after the original precipitating cause has been eliminated, may in significant measure be due to truncal muscle weakness." 28

Low back pain today is one of our greatest medical

problems. Research indicates that the basic cause of pain

and discomfort in the lower back is related to the lack of

abdominal strength and poor postural habits. Statistics

indicate that most adults who suffer from low back pain are relieved. .by exercise . programs. 21, 2 6 ,f 40, f 64 Rasch and Krauer 59 in a study of the two-minute

sit-up test conducted for the United States Marine Corps,

stated that "kinesiological analysis suggest that adequate

trunk strength is a matter of importance to the combat

Marine." They substantiate this statement concluding that

the erect posture in man is maintained by muscular strength.

In Btanding, the body's center of gravity constantly shifts,

so that the individual is continually swaying on a station­

ary base. Equilibrium is for the most part maintained by

alternate contractions of the muscles on the front and back

of the trunk. The authors further contend the necessity

for strong abdominal muscles in Marines is that these

muscles will prevent circulatory collapse induced by grav­

ity, and this could be of importance in prolonged standing. 58 Rasch and Burke note that firm agreement does not exist with regard to strength of the abdominal musculature as a preventative of hernia. In the opinion of some sur­ geons, hernia results from an innate defect in the abdom­ inal musculature or wall, therefore it would appear that preventative oxercise would be to no avail. On the other 29 hand many therapists with a good deal or experience with exercise are convinced that abdominal development con­ tributes to the prevention of hernia*

Summary

The sit-up is the most common means used in testing the strength and endurance of the abdominal muscles; how­ ever, the procedure used varies greatly from test to test* Also, the validity of the sit-up test conducted in the tra­ ditional manner, (legs straight, two-minute time limit), has never been established. Correlations obtained between various strength criterion tests and sit-ups of all types, have been very low, with the highest reported by Berger^ as being a 0.518. The results of most studies, conducted on the sit-up test of abdominal strength and endurance, proved to be insignificant. It seems that the adoption of the two-minute time limit for the sit-up in most physical fit­ ness tests, was based mainly on empirical judgement, using the criteria of administrability, particularly time.

One of the major controversies as far as the sit-up is concerned is the position the legs should be in during test administration. The consensus of opinion appears to favor the hooklying position, with the legs flexed at approximately a sixty-five degree angle. On the question of whether to hold the feet or not during the sit-up test; it was concluded that for those individuals with strong abdominals this is not a factor, but for those with weak abdominal muscles holding the feet can obscure weakness.

Also, sit-ups performed from the longlying position are

thought to be detrimental to the lumbar area by developing

the hip flexor muscles without a corresponding development

of the abdominal muscles. Jn addition, this movement is

felt to place an undue strain on the lumbar area, es­ pecially if the back is arched during the sit-up.

From the literature it would appear that a strong relationship exists between pain and discomfort in the low­ er back and a lack of abdominal strength.

Anthropometric measurements were found to have little influence on an individual’s performance in exer­ cises and tests of the sit-up variety.

From the electromyographic studies of the abdominal muscles» the sit-up and its modifications and variations in the trunk curl and "V” sit-up were found to be the most effective exercises for all abdominal muscles. CHAPTER III

METHODS AND PROCEDURES

This chapter contains a description of the proce­ dures which were followed in the development of a trunk flexion strength-endurance test of the sit-up variety, for college age males. These procedures were divided into three phases, as follows: (l) selection of the proposed trunk flexion strength-endurance test from a number of experimental variations through correlation with valid trunk flexion strength measures for static and dynamic strength; (2 ) validation of the proposed trunk flexion strength-endurance test selected, and determination of the anthropometric measures upon which to base norms for the proposed test; (3 ) the construction of norms.

Phase I - Test Selection

Description of the Subjects

The Phase I sample group consisted of twenty-one subjects who were volunteers from the male student body of

Mayville State College; they ranged in age from eighteen to twenty-seven years with a mean age of twenty years and five months. The subjects ranged in weight from one hundred

31 32 thirty-five to two hundred twenty-eight pounds with a mean weight of one hundred seventy-nine pounds* The height of the subjects ranged from sixty-five and three-fourths to seventy-three and one-fourth inches with a mean height of sixty-nine and one-fourth inches. All subjects were col­ lege males with no known physical or organic deficiencies* To attain a more complete description of the subjects par­ ticipating in Phase I of this study, a questionnaire (Appendix A) was administered to all subjects. Table 1 contains a percentage breakdown of the responses obtained from these questionnaires.

Experimental Test Apparatus Background. The basic concepts of the testing apparatus designed for the experimental tests were based on research findings reported in Chapter II. The function of the apparatus was basically as follows: first, to secure 66 6? the legs in an acute flexed position * and to fix the pelvis in a posterior tilt position thereby placing the hip flexor muscles at a mechanical disadvantage.®' **9* 63 66 67 * ' Secondly, to elevate the buttocks slightly to increase the resistance thus reducing the endurance factor to a marked degree. 5 6 Finally, the arms were to be posi­ tioned such that momentum produced by the speed of arm movement would be eliminated as a factor in the subjects* performance of the proposed test."*

Apparatus Specifications. The experimental test 33

TABLE 1

QUESTIONNAIRE DATA - PHASE I SUBJECTS

1, Home State;

North Dakota - 66 $ Minnesota - 19 % Other - 15 $

2 . Year in College and Ma.ior Fields of Study;

First - 38 % Physical Education - 38 $ Second - l4 % Social Science - 28 Third - 19 £ Business Education - 24 $ Fourth - 29 % Music Education - 10 $

3• Participation in Hi/th School Varsity Athletics;a

Yes - 71 % No - 29 %

4. Varsity Letter Earned in College Athletics t** Yes - 48 % No - 52 %

5 • Physical Activity During Preceding Three Months;

Five days per veek average - 57 % Four days per veek average - 10 $ Three days per week average - 5 * Two days per veek average - 13 % One day per week average - 10 $> Very seldom engage in physical activity - 5 *

6 . Specifically Exercising Abdominal Muscles:

Yes - 48 $ No - 52 #

Medi a n size for the high school the Phase I sub­ jects graduated from was 175 students in the upper four grades.

The enrollment at Mayville State College was approximately 7 5 0. apparatus (Appendix B, Plate I; and Appendix C) consisted

of a vinyl covered plywood base, forty-seven by twenty-four

inches, with two "L" shaped plywood sides, twenty-five

inches high, seven inches long at the top of the "L" and

fifteen inches at the bottom, A plywood backboard, fifteen

inches high was secured to the back of the "I." sides, A

padded seat, twenty by fourteen inches was positioned be­ tween the "L" sides on an incline with the rear raised to a

height of ten centimeters. Xn the initial apparatus used in

Phase I of this study, a two by four board was used as the

leg guide and was placed between the "L" sides at a height of

twenty inches. For testing in Phase II, this portion of the

apparatus was redesigned to insure a constant hip flexion

angle for all subjects. This modification consisted of replacing the fixed board with an adjustable rod. The rod was made adjustable by drilling six holes in the "L" sides, two inches from the rear to center hole, at one and one- half inch intervals with the lowest hole at a height of sixteen and ono-fourth inches to center hole. Two ordinary automobile seat belts were employed to secure the subject in the prescribed position. The lap belt was anchored to the "L" sides on the outside and entered through a slit on the "L" eight inches from the bottom at an angle such that the bottom of the slit was four Inches and the top three inches from the back of the "L" sides, A second seat belt was anchored to the "L" sides and was used to secure the 35 subject's feet to the backboard of the apparatus.

Administration of the Experimental Tests

A large number of possible variations of the trunk flexion movement utilizing the experimental apparatus were screened. The number of experimental variations was re­ duced to three, largely by empirical judgement based on experimental trials conducted personally by the writer.

The experimental tests chosen for detailed analysis in

Phase 1 of this study were as follows: Experimental Test - Variation X. The description following is for the finalized experimental test (proposed trunk flexion strength-endurance test) as developed in

Phase X of this study and utilized for testing in Phases

XX and III (Appendix B, Plate II), Xn the administration of this test, the subject was placed in the supine position on the experimental apparatus. His legs were flexed over the rod, which was positioned approximately four inches below the popliteal space (Appendix B, Plate XIX), and se­ cured with a seat belt across the ankles tightened so the subject's heels came in contact with the backboard of the apparatus. The subject was then instructed to grasp the sides and pull himself forward until his buttocks came in contact with the backboard, in this position the lap belt was fastened securely to stabilize the pelvis.

After the subject was in the proper position, ho was instructed to place his arras through the arm loops attached to either side of the belt which had been previ­

ously placed about the subject's torso immediately below his rib cage (Appendix B, Plate IV). He was instructed to

position the loops just above his elbows and to fold his

arms placing his hands flat on the sides of his chest under

his arms. The subject was now in the starting position and

ready to commence the test. The test consisted of curling-

up so that both the subject's arms came in contact with his

quadriceps and returning so that his head touched the base

of the testing apparatus. This movement constituted one

repetition, the subject's score for this test was the max­

imum number of repetitions that could be'completed with no

time limit; however, if the subject paused in the starting

position for longer than three seconds between repetitions

his test was terminated. Other special instructions given the subjects included: (l) both arms must touch the quad­ riceps simultaneously; (2 ) the head must touch the base

after each repetition; (3 ) the trunk flexion movement should be deliberate and at a moderate rate to eliminate body bounce and momentum as greatly as possible.

Experimental Test - Variation IX. This variation was performed exactly as variation I with one exception, that being the position of the arms (Appendix B, Plate V).

In this tost the hands were interlaced behind the neck with

the arms along the head elbows pointed up. The subject curled-up so that his elbows came in contact with his quad­ 37 riceps and returned so that his head touched the base of the apparatus. In addition to the special instructions noted for variation I, the subject was told he must keep his hands interlaced behind his neck throughout the test. Experimental Test - Variation III. The subject was placed in the apparatus as in variation I and II. In this test, the subject curled-up so that the angle formed by a line from the top of his head to the crest of the ilium and along the floor in the direction of his legs was 1 1 5 degrees (Appendix B, Plate VT). The score for this test was the total number of seconds this position could be maintained isometrically. An additional apparatus was constructed for 3 3 this test to control the height of the isometric curl-up. The subjects were given instructions asto the commands that would be used to execute test variation III. Upon the command "Ready", the subject was to tuck his chin so that it would come in contact with his chest; next, the command "Up", was issued and the subject would curl-up, keeping his chin on his chest, until the top of his fore­ head would come in contact with a rod on the apparatus, m e subject was told to maintain this position as long as possible. The time began the instant the subject reached the prescribed position, and ended when the proper height could no longer be held.

Administration of the Static Trunk Flexion Strength Teat

Instrument. The static strength of the abdominal 38

and anterior trunk muscles was measured using Clarke's

trunk flexion strength test, modified so that the subject

was supine in the hooklying position (Appendix B f Plate

VXI). This test employs the cable tensiometer as a record­

ing device. The tensiometer was originally adopted by

Clarke for determining the strength of muscle groups. 12

The tensiometer measured strength of the abdominal and

anterior trunk muscles by registering the amount of tension

placed on a cable when the subject exerted a force by pul­

ling on one end of the cable while the other end was se­

cured to the base of the testing table.

Reliability of procedures. The investigator's

ability to test reliably the static strength of the abdom­

inal and anterier trunk muscles by means of the trunk

flexion strength test was determined by a reliability

coefficient using the test-retest method.

The twenty-one subjects were administered two

trials of the static trunk flexion strength test; the

reliability coefficient obtained between the two sets of

test scores was 0,835*

Method. The subject was placed in the supine position on the testing table, with his upper body over the opening, A body strap was placed around the subject's chest as high as possible under his arms; he then folded his arms across his chest and flexed his legs so that they formed a sixty-five degree angle. 39 With the subject in this position, the cable from

the body strap was secured at a ninety degree angle to the base of the testing table, and a testing assistant held the subject's feet securely to the table. The tester then applied the tensiometer to the cable and the subject was instructed to curl his head and shoulders up as forcefully as possible with a steady pull. The subject was verbally motivated until no further increase in strength registered on the tensiometer.

Administration of the Dynamic Trunk Flexion Strength Test

Instrument, The dynamic strength of the abdominal and anterior trunk muscles was measured using a one repe­ tition sit-up performed with maximum load (Appendix B,

Plate VXIl), Traditionally isotonic or dynamic strength has been defined in terms of weight lifted or moved through a distance. In an effort to meet this requirement, a series of barbell plates was used. The plates were manu­ factured in five pound increments ranging in size from ten pounds to seventy-five pounds; however by attaching an additional two or three pound plate to any of these plates this test was given additional discriminating power. All lifts were made from the supine, hooklying position on a carpeted floor; barbells were utilized to stabilize the subject's feet.

Reliability of procedures. The investigator's ability to test reliably the dynamic strength of the ab­ dominal and anterior trunk muscles by means of the one rep­ etition maximum sit-up was determined by a reliability coefficient using the test-retest method. The twenty-one subjects were administered two trials of the dynamic trunk flexion strength test; the reliability coefficient obtained

between the two sets of test scores was 0 .9 7^- Method. The subject was placed in the supine position, with his legs flexed at approximately a sixty- five degree angle, feet anchored by a barbell. The subject

held a weight behind his neck with his hands, arms held along the sides of his head elbows pointing upward. From

this position the subject was instructed to execute a sit- up, A successful trial consisted of one complete sit-up to the point where the trunk was vertical with the floor. The subjects were given verbal encouragement in the execution of this test.

The subjects were given an orientation testing period to predetermine approximately what their maximum load for the one-repetition maximum sit-up was. During the actual administration of the test, the subjects initially attempted, after a warm-up, a sit-up with the load pre­ viously determined to be their maximum. If the attempt was successful, the subject rested throe minutos and attempted a higher load for his next trial, if the subject was un­ successful in his first attempt, he was instructed to select a lighter load for his next trial, and then proceed to work toward his maximum from tho point of his first

successful attempt. This process was repeated until the subject was unsuccessful in three consecutive trials with a given load.

Testing Procedure - Phase I_ All tests for Phase I of this study were admin­ istered in the weight training and wrestling rooms of the fieldhouse at Mayville State College. Environmental con­

ditions wore controlled as much as possible. Persons ad­ ministering the tests and the subjects comprising the group being tested were the only individuals in the room when the testing was being conducted.

After the experimental equipment had been assembled, a brief pilot study was conducted. The purposes of this pilot study were twofold: first, to familiarize the tester with the use of the equipment and secondly, to determine the effectiveness of the equipment and procedures. A few difficulties in both equipment and procedures were discov­ ered and necessary corrections were made. Ten volunteer students from a required physical education class served as subjects for the pilot study. From the pilot study, stand­ ardized instructions were developed and the length of the testing period was estimated to assist in scheduling sub­ jects for testing in Phase I. kz Phase I data were collected in December, 1971* The

subjects were assigned to four groups on the basis of free

time in their class schedules, this was done so that the

testing would not conflict with the subjects1 normal class

commitments* The period of testing lasted eight days, test

period one was on a Friday, and test periods two, three and

four were on Monday, Wednesday and Friday of the following

week. The subjects comprising each group reported at a pre­

arranged time each testing period. The testing periods

were conducted between 12:00 noon and 6:00 P, M, each test­

ing day. Each subject was required to be dressed in gym

shorts, t-shirt and socks for all testing periods.

Four testing periods were determined to be the min­

imum number of periods necessary to collect all data, the need for this many test periods was due in most part to the

time consuming process for administering the dynamic trunk

flexion strength test. A random rotation design was used

to determine the order of test variables for test period

three in an effort to negate any learning or fatigue factors

that might have affected the results of the investigation.

The rotation design is shown in Table 2.

It was decided to eliminate both the static and dynamic criterion measures of trunk flexion strength from

the rotational design. The time allotment for each test period and the time required to administer the dynamic trunk flexion test was again the determining factor. These Two variables were administered in alternate order to the groups in test period two, the order of administration was then reversed for test period four.

TABLE 2

PHASE I - TESTING SCHEDULE

Testing Periods

Subjects 1 2 3 4

Group 1 (N = .5) A , G B, A± C, D, E, F a 2 , bx

Group 2 (N ss 5) A, G Ax, B D, E, F, C B l* A 2 Group 3 (N - 5) A , G B, A1 E, F, C, D a 2 , b 1

Group 4 (N = 6) A , G Alf B F, C, D, E B l* A2

A - Dynamic Trunk Flexion Tost, Orientation

A^ - Dynamic Trunk Flexion Tost, Trial I

Ag - Dynamic Trunk Flexion Test, Trial II

B - Static Trunk Flexion Test, Trial I

B1 - Static Trunk Flexion Test, Trial II

C - Experimental Test - Variation I

D - Experimental Test - Variation II

E - Experimental Test - Variation III

F - AAIIPER Two-Minute Sit-up Test

G - Collection of Anthropometric data and administration of Questionnaire 44

Phase XI - Validation of the Proposed Test

Descript■on of the Subjects

The Phase II group consisted of eighty male subjects who were volunteers from required physical education and general education classes at Mayville State College; they ranged in age from eighteen to twenty-seven years with a mean age of twenty-one years and two months. The subjects ranged in weight from one hundred thirty-five to two hun­ dred sixty-three pounds with a mean weight of one hundred eighty-two pounds. The height of the subjects ranged from sixty-five and three-fourths to seventy-six and one-fourth inches with a mean height of sixty-nine and three-fourth inches. All subjects were college men with no known phys­ ical or orgi'fiic deficiencies. To better describe the sub­ jects , the questionnaire administered to the Phase I sub­ jects was also administered to the eighty Phase II subjects.

Table 3 contains the percentage breakdown of responses ob­ tained from the Phase II subjects on the questionnaire.

Methods Employed in the Validation of the Proposed Test

The test selected for further analysis in this phase of the study was the Experimental Test - Variation I

(Proposed Trunk Flexion Strength-Endurance Test). A de­ tailed description of this test has been given previously

(page 3 5).

The eighty subjects utilized in the establishment 45

TABLE 3 QUESTIONNAIRE DATA - PHASE II SUBJECTS

1* Home State:

North Dakota - 72 $ Minnesota - 18 $ Other - lO ^

2. Year in College and Major Fields of Study;

First - 18 yx Physical Education - 32 % Second - 10 % Social Science - 22 $ Third - 23 Business Education - 20 % Fourth - $ Other - 26 %

3. Participation in High School Varsity Athletics: Yes - 73 % No - 27 ^

4* Varsity Letter Earned in College Athletics:**

Yes - 30 ^ No - 70 % 5* Physical Activity During Preceding Three Months;

Five days m-r week average - 16 % Four days per week average - 16 % Three days per week average - 21 % Two days per week average - 25 % One day per week average - 8 Very seldom engage in physical activity - 1^ %

6. Specifically Exercising Abdominal Muscles; Yes - 21 % No - 79 %

Median size for the high school the Phase II sub­ jects graduated from was 1 7 5 students in the upper four grades.

The enrollment at Mayville State College was approximately 750* 46

of* validity and reliability for the proposed trunk flexion

strength-endurance test, were each given an orientation

trial of the criterion measure, the dynamic trunk flexion

strength test* The specific procedure for the adminis­

tration of this test was outlined in detail previously

(pages 39-4o).

The validity of the proposed test was determined

by computing a correlation coefficient with the criterion

measure•

Twenty-nine of the eighty subjects volunteered to

take a second trial of the proposed trunk flexion strength-

endurance test* These scores were used in the computation

of a reliability coefficient for the proposed test*

Methods Employed in Determining the Bases for Norms

It was decided, on the basis of the insignificant

relationships reported between anthropometric measurements

and movements of the sit-up variety,^^to study only three basic anthropometric measurements for possible use as bases for test norms* The anthropometric measures and methods of collecting data were as follows:

Weight» The subject stood in the center of the scale platform with weight evenly distributed through both lower limbs. Measurements were made with subjects in gym shorts and stockings. Weight was recorded to the nearest pound.

Standing Height. The subject stood in stocking 47 feet with heelst buttocks, and upper part of back in con­

tact with an upright board attached to a base and inlaid

with a wooden square operating in a vertical groove. The

head was held in a natural position and the square was

brought down upon the head firmly and the reading made at

the base of the square to the nearest quarter inch.

Sitting Height. The subject was in a sitting

position on an eighteen inch bench, which was on the base

of the upright board, with back and head touching the

vertical plane of the measuring instrument. The feet of

the subject rested on the floor with the thighs flexed at

near right angles to the trunk. The square was brought

down on the top of the head, as in taking standing height;

the measurement was recorded to the nearest quarter inch.

Sitting height was obtained by deducting the height of the bench from the height measurement taken.

Statistical Analysis

The bases for the establishment of norms for the proposed trunk flexion strength-endurance test were deter­ mined by computing intercorrelations between all anthropo­ metric, strength criterion, and experimental variables.

The level of significance of the correlations was found by applying the Mt" test of significance,

Testing Procedure - Phase II

The Phase II test variables were administored in 48 the weight training and wrestling rooms of the fieldhouse at Mayville State College. The conditions were similar to those imposed for testing in Phase X.

Phase II data were collected in January, 1972. The subjects were tested as a single group, however the time of test administration varied for the subjects as they report­ ed for testing in groups of eight at prearranged times from

10:00 A.M, to 6:00 P.M. each testing day. The period of testing lasted eight days, test periods one, two, and three, were on Monday, Wednesday, and Friday, test period four was on Monday of the following week.

Test period one was devoted to collecting anthro­ pometric measurements and completing the questionnaire, the procedures to be employed and schedules for Phase II testing were also discussed during this period. Period two was devoted to orientating the subjects to the dynamic trunk flexion strength test. In period three the actual test data were collected for establishing validity for the proposed test, the order of administration for the two tests was rotated for every other subject. All of the sub­ jects were requested to return on a voluntary basis to take a second trial of the proposed trunk flexion strength- endurance test, twenty-nine subjects volunteered and re­ turned for test period four. The Phase II testing schedule is presented in Table 4. 49

TABLE 4

PHASE II - SCHEDULE OF TESTING AND NUMBER TESTED EACH PERIOD

Testing Period

Variables 1 2 3 4

Anthropometric Measurements 80

Questionnaire 80

Dynamic Trunk Flexion Test Orientation Trial 80 Trial I 80

Proposed Test (Exp, Test-Var, I) Trial I 80 Trial II 29

Phase III - Construction of Norms

Description of the Sub.jects

The Phase III group consisted of a total of 490

college men, ages eighteen through thirty-three with a mean

age of 19*38 years, who were enrolled in required physical

education and general education classes at colleges and

universities in North Dakota. The selection of classes for

testing was dependent upon the instructors' and students' voluntary cooperation. All subjects were college males

with no known physical or organic deficiencies. The dis­

tribution of subjects utilized in the construction of the

test norms is presented in Table 5* 50

TABLE 5

DISTRIBUTION OF SUBJECTS UTILIZED IN THE CONSTRUCTION OF NORMS

Age Breakdown

Institution 18 19 20 21 22 23 2k 25-33

Mayville State College (N = 153) 3^ 27 22 37 19 7 3 U

Valley City State College (N = 7*0 22 20 8 9 6 1 2 6

North Dakota State University (N = 197) 112 7^ h 1 1 2 1 2

University of North Dakota (N = 66) 36 25 3 1 1

Method of Norm Construction

Initially, norms were to be constructed for college men which would indicate the variations in trunk flexion strength and endurance resulting from differences in anthro­ pometric measurements. Subsequently, however, statistical analysis of the data revealed that no significant relation­ ship existed between anthropometric measurements and per­ formance on the proposed trunk flexion strength-endurance test. Consequently, the form of norm table constructed was the Hull Scale based on the differentiation of raw test

scores by magnitude only,

Hull Scalo, The Hull scale was constructed accord- Lq ing to the procedures outlinod by Mathews, The statis­ tical procedures followed were:

1. Compute the mean and standard deviation for the

Phase 111 data.

2. Place the numbers 1 to 100 in a column, and opposite 50 place the mean of the data.

3. Multiply the standard deviation by 3*5 and divide this by 50.

4. Consecutively add this number to the mean for determining points 51 to 100 on the 0 to 100 scale; and consecutively subtract this number from the mean for determining assigned values from 49 to 0.

A second norm table was constructed that would simply provide the basis for a descriptive comparison of a raw score obtained on the proposed test. This table con­ tained five descriptive categories as follows: (l) Excel­ lent, (2) Good, (3) Average, (4) Low Average, (5 ) Poor; each category included 1.2 standard deviations.

Prior to the construction of the norm tables, the

Phase III data were placed in a frequency distribution and tested for normality by the chi-square method.^ CHAPTER IV

ANALYSIS OF THE DATA

In this chapter, the data for the experimental trunk flexion strength-endurance tests, the criterion meas­ ures of trunk flexion strength, and the anthropometric measurements are presented. The reporting of the data collected is presented in three phases to coincide with the three major phases or steps followed in the development of a trunk flexion strength-endurance test of the sit-up variety. In Phase I, intercorrelations, descriptive sta­ tistics and comparisons of correlations for data collected in the selection of the proposed trunk flexion strength- endurance test from among three experimental variations are presented. Phase II contains the descriptive statistics for all variables, the validity and reliability data for the proposed trunk flexion strength-endurance test, and an analysis to determine the most appropriate time limit for the proposed test. Presented in Phase III are the norm tables developed from the proposed test data.

Phase I

Statistical Analysis

52 53 The tasks in the analysis of the Phase I data were to: (l) determine the reliability and appropriateness of the criterion trunk flexion tests; (2) determine the

validity of the three experimental tests; (3) determine if any of the experimental tests were superior to the two- minute sit-up test as administered in the AAHPER Youth Fit­ ness Test, and; (4) to determine the effect anthropometric

measurements, height, sitting height, and weight, had on the test results* Pearson product-moment correlations were used to determine the relationship between any two vari­

ables and were computed by use of the raw score formula. The level of significance of the correlations was found by applying the "t" test of significance. In Phase I of this study the .01 level of significance was considered accepta­ ble. The significance of the difference between correlated r 1s was computed by use of the Hotelling t-ratio formula. Descriptive statistics in terms of the mean, standard dev­ iation, and range were computed for all variables in Phase I and are presented in Table 6,

Criterion Test Reliability

The twenty—one Phase I subjects were given a test- retest sequence on different days to establish test reli­ ability for both the static and dynamic trunk flexion

strength tests. The mean for the first static trunk flexion test was 67.24 tensiomotor units with a SD of 15.57. The 54

TABLE 6

PHASE I - DESCRIPTIVE STATISTICS

Unit of Variable Measure Mean SD Range

Static T. F. Tensio- Strength Tost meter Unit Trial I 67.2^ 15.57 37-100 Trial II 71 .10 17.20 42-100 Lesser 66.33 16.00 47-100 Greater 72 .00 16.53 42-100 Dynamic T. F. Strength 'Test Pounds

Trial I 38,00 13.22 20-70 Trial II 39.48 12.73 25-70 Lesser 37.43 13.09 20-70 Greater 40.05 12.77 25-70 Experimental Tests Number

Variation I 27.19 8.6l 17-50 Variation II 28.24 11.34 6-58 Variation III 38.00 15.90 12-68 AAHPER Two-Minute Sit-up Test Number 64.19 10.59 47-80 Anthropometric Measurements

Height Inches 69.24 2.02 65.75-73.25

Sitting Height Inches 35.55 1.32 33.50-37.75

Weight Pounds 178.86 24.47 135-225 mean for the retest was 71*10 tensiometer units with a SD

of 17*20. The coefficient of correlation was 0.835* The mean for the first dynamic trunk flexion strength test was 38 pounds with a SD of 13.22. The mean for the retest was 39*48 pounds with a SD of 12.73* The correlation coef­ ficient was 0.974. The data are summarized in Table 7*

TABLE 7 SUMMARY OF DATA ON CRITERION TEST RELIABILITY

Test N Mean SD r

Static Trunk Flexion Strength Test

Test I 21 67*24 15*57 0.835 Test II 21 71*10 1 7 *2 0 Dynamic Trunk Flexion Strength Test

Test I 21 38.00 13*22 0.974 Test II 21 39.48 12.73

Selection of the Proposed Test

The selection of a proposed trunk flexion strength- endurance test for further development and study in Phase II of this study was made by computing validity correlations between the experimental test variations and the criterion measures for static and dynamic trunk flexion strength. Variation I of the experimental tests correlated the high­ est to both criterion measures; correlating 0.498 to trial

IX of* the static trunk flexion strength test, and 0.834 to

trial II of the dynamic trunk flexion strength test.

Variation II of the experimental tests was quite similar to variation I as indicated by correlations 0.791 to the dynamic trunk flexion test, trial I, and 0.312 to the static trunk flexion test, trial II. Variation III cor- 4 related essentially the same as variations I and II to the

static trunk flexion test, 0.450, but was considerably lower on the dynamic trunk flexion strength test correlat­ ing 0.447 to trial I and 0.327 to trial II. All intercor­ relations for the experimental tests, the criterion strength tests computed for trial I and II as well as for the greater and lesser trials, and the anthropometric measurements, height, sitting height, and weight, are presented in Table 8.

The .01 level of significance was considered acceptable for the correlations in Phase I of this study.

Therefore, with 19 degrees of freedom a correlation must be

0.5487 or greater to bo considered significant. On this basis the experimental test-variation III was declared invalid and eliminated from further consideration as a possible test of trunk flexion strength-endurance.

The selection of tho most appropriate experimental test was not clearly delineated by the correlation coef­ ficients as evidenced by the similarity of correlations TABLE 8

PHASE I - INTERCORRELATTONS

Variables 2 3 4 5 6 7 8 9 10 11 12 13 l4 15 1. Static T. F. Test-Trial I .835 .993 .849 .458 .544 .506 .497 .375 .189 .250 .366 .195 .304 .350 2. Static T. F. Test-Trial II .860 .995 .596 .598 ,6o4 .574 .498 .312 .450 .438 .101 .120 .256 3. Static T. F. Test-Lesser .865 .475 .553 .523 .507 .397 .197 .276 .360 .184 .252 .311 4. Static T, F. Test-Greater .573 .599 .600 .575 .488 .312 .437 .452 .096 .167 .294 5. Dynamic T. F, Test-Trial I .974 .995 .986 .816 .791 .447 .540 .026 -.045 .275 6. Dynamic T. F. Test-Trial II .986 .995 .834 .781 .327 .567 -.142 -.007 .399 7. Dynamic T. F. Test-Lesser .988 .833 .788 .422 .559 .021 .059 .304 8. Dynamic T. F. Test-Greater .823 .790 .399 .552 .049 .OlO .371 9. Exp. Test-Var. I .853 .548 .590 -.123 .027 .161 10. Exp. Test-Var. II .391 .659 -.020 -.095 .179 11. Exp. Test-Var. III .241 -.058 -.083--.273 12. 2-Minute Sit-up .027 .046 .238 13. Height .684 .209 14. Sitting Height .326 15. Weight Levels of Significance: (19 degrees freedom) .01 Level = .55 U( .05 Level = .43 *>1 58 obtained for variations I and II. To determine if* a sig­ nificant difference between means of variation I and II

existed a "t" test of difference was made. This comparison of means, presented in Table 9» also failed to reveal any

significant differences between variations I and II.

TABLE 9

COMPARISON OP MEANS BETWEEN VARIATION I AND VARIATION II

Tests r Diff. Mean S.E. Diff Mean t-ratio

Variation I Variation II 0.853 1.05 1.36 0.77

.01 Level of Significance = 2.8^5 (df > 20)

The experimental test selected for further investi­ gation as a result of observations and findings in Phase I of this study, was the experimental test-variation I. This test was an isotonic or dynamic test in which the arms were folded and secured across the chest. The selection of this test was based primarily on the fact that it correlated higher, although not significantly higher (Table ll)» than variation II to the dynamic trunk flexion strength test.

Also taken into consideration was the fact that the cor­ relation obtained between variation I and the dynamic criterion test was significantly different from the cor­ relation obtained betweon the AAHPER two-minuto sit-up test and the dynamic criterion test; similarly, thore was no 59 significant difference found for variation XI. Finally, through observation during the administration of the tests, and analysis of test results, it was noted that the arm

movement in variation II appeared to be more of a factor in test results than in variation I.

Tables 10 and 11, contain comparisons for all cor­

relations obtained for the three experimental tests and the

AAHPER two-minute sit-up test with both the static and

dynamic strength criterion tests.

Discussion - Phase I

Anthropometric Measurements. From the data present­

ed in Phase I of this 3tudy it appears that the anthropo­ metric measurements height, sitting height, and weight, have no significant influence on an individual's performance on tests of the sit-up variety.

Experimental Test Reliability. It was noted that when the means of variations I and II were compared (Table

9), there was no significant difference between means of

the two tests. This insignificant t-ratio and the rela­

tively high correlation between the two variations would appear to indicate that the experimental test in the iso­

tonic or dynamic version is quite reliable, regardless of arm position.

Criterion Strength Tost for Phase II. The insig­ nificant correlation for the experimental tests, variations 6o

TABLE lO

COMPARISON OF CORRELATIONS WITH THE STATIC TRUNK FLEXION STRENGTH TEST AS THE COMMON VARIABLE

Variables r t

Static Trunk Flexion Strength Test-Trial I

Experimental Test-Variation I .38 .0 5 Two-Minute Sit-up Test .37 Experimental Test-Variation II .19 1,00 Two-Minute Sit-up Test .37

Experimental Test-Variation III .25 1 .7 0 Two-Minute Sit-up Test .37 Experimental Test-Variation I .38 1.65 Experimental Test-Variation II .19

Experimental Test-Variation I .38 1.08 Experimental Test-Variation III .25 Experimental Test-Variation II .19 .34 Experimental Test-Variation III .25

Static Trunk Floxion Strength Test - Trial II

Experimental Test-Variation I .50 .33 Two-Minute Sit-up Test

Experimental Test-Variation II .31 .75 Two-Minute Sit-up Test .44 H H Experimental Test-Variation H .45 .04 Two-Minute Sit-up Test .44

Experimental Test-Variation I .50 1.76 Experimental Test-Variation II .31

Experimental Test-Variation I .50 .27 Experimental Test-Variation III .45

Experimental Test-Variation II .31 .61 Experimental Test-Variation III .45

aSignificant beyond the .01 level of* confidence. 61

TABLE 11

COMPARISON OF CORRELATIONS WITH TIIE DYNAMIC TRUNK FLEXION STRENGTH TEST AS TIIE COMMON VARIABLE

Variables r t

Dynamic Trunk Flexion Strength Test - Trial I

Experimental Test - Variation I .82 2.31b Two-Minute Sit-up Test .54

Experimental Tost - Variation II .79 2.09 Two-Minute Sit-up Test .54

Experimental Test - Variation III .45 .98 Two-Minute Sit-up Test .54

Experimental Test - Variation I .82 .41 Experimental Test - Variation II .79 Experimental Test - Variation I .82 2.89a Experimental Tost - Variation III .45 Experimental Test - Variation II .79 2.20b Experimental Tost - Variation III .45 Dynamic Trunk Flexion Strength Test - Trial II

Experimental Test - Variation I .83 2.22b Two-Minute Sit-up Tost .57 Experimental Test - Variation II .78 1.73 Two-Minute Sit-up Tost .57 Experimental Test - Variation III .33 l.o4 Two-Minute Sit-up Test .57 Experimental Test - Variation I .83 .72 Experimental Test - Variation II .78

Experimental Test- Variation I .83 4.17a Experimental Test- Variation III .33 Experimental Test - Variation II .78 2.89a Experimental Tost - Variation III .33

Signifleant beyond the .Ol level of confidence. Significant beyond tho .05 level of confidence* 62 I and XX, with the static trunk flexion strength test, and the highly significant correlation of these tests with the dynamic trunk flexion strength test pose a question as to the validity and appropriateness of utilizing a static test as a criterion measure for a dynamic test# Tests for static strength are easily administered and require little time. Maximum static strength can be measured in one or two trials. However, to measure dynamic strength a trial and error procedure must be used# The load progressively increased until the maximum load for one complete movement is attained. Because of the effects of fatigue and the greater time involved to test dynamic strength, static strength tests have been employed more often in research studies. Although the static strength test would appear to be the most popular test to use as a criterion measure, the dynamic strength criterion was chosen for Phase II of this study for the following reasons: (l) The results of the Phase I testing indicated the dynamic trunk flexion strength test to be a more re­ liable test than the static trunk flexion strength test. (2) The relationship of dynamic or isotonic strength and static or isometric strength has been studied with the opinion being widespread that the two measure si irply different muscular activities and effects. Hunsicker, 32 who reviewed the literature extensively, stated that there is a difference between static and dynamic strength and 63 that the mathematically determinable correlation between

the two is not high. (3) Finally, in light of the above

information, and because the experimental test chosen for

further study in Phase II was dynamic in nature, it would

appear that to obtain the most valid results the criterion

test should also be dynamic in nature.

Experimental Test - Variation I Revisions. As a

result of the testing in Phase X, some modifications were

deemed necessary for the experimental test - variation I

(Proposed Trunk Flexion Strength-Endurance Test). The

first modification made was to the apparatus, and consisted

of replacing the fixed leg brace with an adjustable rod to

insure a relatively constant hip flexion angle for all sub­

jects regardless of their size. The reader is referred to

page 3^ for additional discussion of this modification.

The second change made was the addition of abelt to im­

mobilize the subject*s arms. The belt, with two arm loops

attached, was placed around the subject*s chest Just below

his rib cage, the subject's arms were extended through the

arm loops so that the loops were above the elbows, the sub­

ject would then fold his arms placing his hands flat on the

sides of his chest under his arms. Additional discussion of this modification was conducted on pages 35-36.

Phase XX

Statistical Analysis 6k The tasks in the analysis of the Phase II data were to determine the validity and reliability of the proposed trunk, flexion strength-endurance test (experimental test- variation l), and to determine what effect the anthropo- metric measurements, height, sitting height, and weight, had on the test results. Pearson product—moment cor­ relations were used to determine the relationship between any two variables and were computed by use of the raw score formula. The intercorrelations computed for Phase II of this study are presented in Table 13. The level of sig­ nificance of the correlations was found by applying the ” ttf test of significance. The proposed trunk flexion strength- endurance test scores were recorded in ten—second intervals and were analyzed to determine the most appropriate time interval for administration of the test. Descriptive sta­ tistics in terms of the mean, standard deviation, and the range were computed for all variables and are presented in Table 12.

Validity and Reliability of the Proposed Teat

The validity and reliability of measures is im­ portant in the evaluative procedures of any investigation. As this was a problem in test construction studies dealing with validity and reliability were of paramount importance. Validity. Using the dynamic trunk flexion strength test as the criterion test, eighty subjects participated in 65 TABLE 12

PHASE II - DESCRIPTIVE STATISTICS

Variable Unit Mean SD Range

Dynamic Trunk Flexion Test

Trial I (N=80) Pounds 38.93 1 0 .0 6 12 65 Trial II (N=29) 39.24 11.25 25 - 65

Proposed Test

Trial I (N=:80> Number 26.64 8.96 0 47 Trial II (N=29) 27.76 7 .1 6 16 - 44

Height Inches 69.71 2,49 65.75 - 76.25

Sitting Height Inches 35.73 1.39 31.50 - 39.50

Weight Pounds 1 8 1 .8 3 23.77 135 - 263

TABLE 13

INTERCORRELATIONS FOR PHASE II VARIABLES

Dynamic Trunk Sitting Variable Flexion Height Height Weight

Proposed Trunk Flexion P

Strength-Endurance Test O -0.033 0.123 0.205

Dynamic Trunk Flexion Strength Test -0.100 0.070 -0.060

Height 0 .700a o.34oa

Sitting Height 0.34oa

Signifleant beyond the .01 level of Confidence. 66

the study to establish the validity of the proposed trunk flexion stren^th-endurance test. The mean score in repe­

titions for the proposed test was 26.64 with a SD of 8 .9 6.

The mean score in pounds for the dynamic trunk flexion strength test was 38.93 with a SD of 10.06. The coef­ ficient of correlation between the proposed test and the

dynamic trunk flexion test was 0.77. The data on validity are summarized in Table 14.

TABLE 14

SUMMARY OF DATA ON TEST VALIDITY

Test N Mean SD r

Proposed Trunk Flexion Strength-Endurance Test 80 26.64 8 .9 6 Dynamic Trunk Flexion 0.77 Strength Test 80 38.93 1 0 .0 6

Reliability. The typical procedure in checking reliability is to correlate scores on repeated trials of

the test. Correlations indicate the extent to which indi­ viduals maintain their relative positions from trial to trial, but one must also consider the extent to which in­ dividuals change from trial to trial. One should there­ fore determine if the means of the group on the two trials are significantly different. To be truly reliable a test must yield consistent results from day to day. For this reason a testing design was adopted which allowed for test­ 67 ing the subjects with the proposed trunk flexion strength-

endurance test on two separate days.

The estimate of the reliability for the proposed

test in Phase IX of this study was based on an examination

of coefficients of correlation and the t-ratio of difference

between the means on repeated trials of a test. With an N

of twenty-nine, the correlation must be 0,4678 or greater

to be significant at the .01 level of confidence. The " t1'

for this study must be 2.763 to be significant at the .01

lev©!. In order to be acceptable in terms of test relia­

bility, there must be a relatively high correlation and

an insignificant "t".

The mean score in number of repetitions for trial I

of the proposed test was 27.31 with a SD of 8,33* The mean

score in trial II for the proposed tost was 27*76 with a SD

of 7.16. The reliability correlation and the t-ratio of

the difference between the means of repeated trials of the

proposed trunk flexion strength-endurance test are present­

ed in Table 15, As revealed in this table, the proposed

test appears to be a reliable test.

Influence of Anthropometric Measures on Test Results

It would appear that the anthropometric measure­ ments, height, sitting height, and weight would affect the performances on sit-up tests because the heavier person has

to overcome the gravity pull plus his body weight in per- 68

TABLE 15

SUMMARY OF DATA ON TEST RELIABILITY

Test r Diff Mean SE Diff Mean t-ratio

Proposed Test

Trial I Trial II 0.91 .k5 ,382 1.18

*01 level of significance = 2,7 63 (df — 28) forming a sit-up and a taller person has a longer range of motion in his sit-up movement. The correlations presented in Table 8 and Table 13 indicate that there is no signif­ icant relationship between the physical dimensions, height, sitting height, and weight to performance on the proposed trunk flexion strength-endurance test, the criterion mea- ures for trunk flexion strength, or the AAHPER two-minute sit-up test. These findings concur with those reported in the literature.1^ 16’ 17• 60

Selection of a Time Limit for Administration of the Proposod Trunk Flexion Strength-Endurance Test

To determine the most appropriate time limit for administration of the proposed test so as to primarily measure strength rather than endurance, the Phase II sub­ jects1 scores were recorded at toi-second intervals. The results are shown in Table 16, The scores, the means, total scores, and the decrease in scores during each ten- 69 second interval are indicated as are the number of* subjects who were unable to complete a single repetition on the pro­ posed test (zrero scores) ~at each ten-second interval. Also indicated is the correlation between the proposed test and the criterion test at select intervals.

TABLE 16

DESCRIPTIVE STATISTICS OF THE PROPOSED TEST SCORES AT TEN-SECOND INTERVALS (N = 80)

Score Decrease Number Decrease In Means of Range Inter­ Total Each Each Zero In val Scoros 10-Sec. Moans 10-Sec. Scores Scores r

10, 553 O 6.91 .00 1 0-10 6.28 0-10 102 502 51 .63 2 454 48 5.68 ,6o .639a 103 5 0-9 l4l . 708a 10<. 313 3.91 1.77 11 0-7 10e 178 2.22 1.69 29 0-6 .744a 5 135 H o 93 85 1 .1 6 1 .0 6 48 0-6 .767a O H 29 64 .36 .80 67 0-4 .770a ____ Significant beyond the ,01 level of confidence.

By visual inspection of Table 16 it is evident that a marked decrease in both means and total scores occurred after the fourth interval and this decrease continued throughout the remaining intervals. Also the number of zero scores began to increaso greatly after interval number four. However, the validity correlations appeared to in- 70

crease slightly with each ten-second 1. It was

noted during the test administration that only two of the

eighty subjects required longer than seventy seconds to

complete the test.

It should be noted that the proposed test was

administered on a "no time-limit" basis and therefore the

subjects, for the most part, were not trying to see how

"fast" they could perform the test or how many repetitions

they could accomplish in a specified period of time*

Since the highest correlation between the proposed

test and the criterion test occurred after the final inter­ val, it would appear logical to recommend the proposed

trunk flexion strength-endurance test be administered with no time limit. Also the trunk flexion movements of the

test wore observed to be performed in stricter fashion when

the subject was not concerned with speed. One of the major reasons the traditional sit-up test is administered with a

time limit is because certain individuals capable of accomplishing very high repetitions would take considerable time to complete the test. 59 * 65 This undesirable feature of the traditional sit-up test was not observed to bo present in the administration of the proposed test.

Finally, it would appoar that for simplicity and ease of administration, the no time-limit test would be superior to a timed test. 71 Phase III

Norm Tables

In order to provide a means of interpreting the scores obtained by college men on the proposed trunk flexion strength-endurance test, a Hull scale norm table, and a five category descriptive norm table were prepared.

The norm tables were developed from testing 490 college men at colleges and universities in North Dakota.

The hypothesis that the norm sample was drawn from a normal distribution was tested by use of the chi-square test. With eight degrees of freedom a chi-square of 15*507 25 is required for significance at the .05 point. The chi- square obtained from the Phase III data was 10.79* thus we may accept the idea that the population from which the sample came is normally distributed on the scale of measurement used. The scale of measurement obtained from the Phase III administration of the proposed test was: mean - 24.95* and standard deviation - 8.68.

Hull Scale Norm Table

The Hull scale is based on the concept of the normal curve and standard deviation divisions of the curve.

The distribution of the Hull scale includes 3*5 standard deviations on either side of the mean. Scales such as the

Hull provide a means for placing various test scores on a common table from 0 to 100. Scaling data enables one to: 72 (l) Interpret an individuals performance relative to the

population from which the scale was developed* (2) Com­

pare scores without references to anthropometric measures.

(3) Group or classify individuals. (4) Compare and average unlike scores, for example, data obtained from

skill testing, fitness testing, track and swimming events may be averaged, thus providing a general index* (5) Pre­ pare norm tables from test data*

The Hull scale, which was constructed from the raw score in repetitions on the proposed trunk flexion strength- endurance test is presented in Table 17• In order to interpret an individualfs performance or. the proposed test, enter Table 17 with the individualfs raw score in repe­ titions on the proposed test and record the corresponding Hull scale score*

Descriptive Norm Table

The second norm table constructed provides a simple descriptive comparison for a raw score obtained on the pro­ posed test. This norm table is based on five divisions of the normal curve, each descriptive division or category thus includes 1.2 standard deviations. Relative to the population for which the norm table was constructed one may interpret descriptively individual standings against the group. Another use for a norm table such as this would be to group or classify individuals. This descriptive norm table is presented in Table 18* 73

TABLE 17

THE PROPOSED TRUNK FLEXION STRENGTH-ENDURANCE TEST HULL SCALE NORM TABLE FOR COLLEGE MEN

Hull Raw Hull Raw Hull Raw Scale Score Scale Score Scale Score

IOO 56 65 34 30 13 99 55 64 34 29 98 63 33 28 12 97 54 62 27 11 96 53 . 61 32 26 95 60 31 25 10 9** 52 59 24 93 58 30 23 9 92 51 57 22 8 91 50 56 _ 29 21 90 55 28 20 7 89 49 54 19 88 53 27 18 6 87 48 52 17 5 86 47L_ 51 26 16 85 50 25 15 4 84 46 49 14 3 83 48 24 13 82 45 47 12 2 81 44 46 23 11 80 45 22 10 1 79 43 44 9 78 43 21 8 77 42 42 7 76 4l 4l 20 6 75 '+0 19 5 74 40 39 4 73 39 38 18 3 72 37 17 2

71 . .... 38 36 1 70 35 16 69 37 34 68 36 33 15 67 32 14 66 35 31 7k

TABLE 18

THE PROPOSED TRUNK FLEXION STRENGTH-ENDURANCE TEST DESCRIPTIVE NORM TABLE FOR COLLEGE MEN

Raw Score Descriptive Range Category

50 - 59 Excellent ON o I Good

20 - 39 Average

10 - 19 Low Average

0 - 9 Poor CHAPTER V

SUMMARY, CONCLUSIONS, AND RECOMMENDATIONS

The primary purpose of this study was to develop

a strength-endurance test, of the sit-up variety, for the

muscles of the abdominal group. In addition to developing

the equipment and methods of test administration, reliability

and validity were studied. A second aspect of this study

was the establishment of the bases of norms for the proposed

trunk flexion strength-endurance test through study of a

select number of anthropometric measures. A final aspect

of this study was to construct norms for the proposed test for use by college age males.

Summary

Procedure

Phase I. The sample group consisted of twenty-one

subjects who wore volunteers from the male student body of

Mayville State College ranging in age from eighteen to

twenty-seven years. Average age, height, and weight, of

the subjocts was as follows: (l) twenty years and five months; (2) sixty-nine and one-fourth inches, and; (3) one

75 76

hundred seventy-nine pounds respectively.

The twenty-one Phase I subjects were assigned to one

of* four groups on the basis of free time in their class

schedules. The Phase X data were collected in four, one-

hour testing periods as follows: (l) Dynamic trunk flexion

strength test, orientation trial; anthropometric measure­

ments, and the administration of the questionnaire. (2)

Criterion measures, dynamic trunk flexion strength test,

trial I; and static trunk flexion strength test, trial I,

(3) Experimental tests, variations I, II, and III; and the

AAHPER two-minute sit-up test. (^) Criterion measures,

dynamic trunk flexion strength test, trial II; and the

static trunk flexion strength test, trial II.

The tasks in the statistical analysis of the Phase

I data wore to determine: (l) the validity of the three

experimental tests; (2) the effect of anthropometric mea­

surements, height, sitting height, and weight, on test per­

formance, and; (3) if any of the experimental tests were

superior to the AAHPER two-minute sit-up test.

To describe the distribution of the test results

the means, standard deviations, and ranges were computed

for all variables. To determine the degree of relationship

between any given variable and each of the other variables,

Pearson product-moment correlation coefficients were com­ puted. The lovel of significance of the correlations was

found by applying the "t" test of significance. The sig­ 77

nificance of the difference between correlated r's was com­

puted by use of the Hotelling t-ratio formula.

Phase II, The sample group consisted of eighty

male subjects who were volunteers from required physical

education and general education classes at Mayville State

College* The subjects ranged in age from eighteen to

twenty-seven years. Average age, height, and weight, of

the subjects was as follows: (l) twenty-one years and two months; (2) sixty-nine and three-fourths inches, and; (3)

one hundred eighty-two pounds respectivoly.

The Phase II portion of the study consisted of:

(1) the determination of the validity and reliability of

the proposed trunk flexion strength-endurance test, and;

(2) the determination of the basis for norms through study of anthropometric measures.

The Phase II data were collected in four one-hour periods as follows: (l) This test period was devoted to collecting anthropometric measurements and completing the questionnaire, the procedure employed and schedules for

Phase II testing were also presented. (2) Period two con­ sisted of orientating the subjects to the dynamic trunk flexion strength tost. (3) During this period the actual test data were collected for establishing validity for the proposed test. {k) All of the subjects were requested to return on a voluntary basis to take a second trial of the proposed tost, twenty-nine subjects returned to take trial 78

IX of the proposed test.

Statistical analysis consisted of determining the

validity and reliability of the proposed testf and the

effect anthropometric measurements, height, sitting height,

and weight, had on the subjects* test performance* Pearson

product-moment correlations were used to determine the

relationship between any two variables, the significance of

the correlations were determined by applying the "t" test

of significance. The proposed trunk flexion strength-

endurance test scores wore recorded in ten-second inter­ vals and were analyzed to determine the most appropriate

time interval for administration of the test* Descriptive statistics in terms of the mean, standard deviation, and

the range were computed for all variables.

Phase III. This sample group was comprised of ^90 male subjects who were onrolled in required physical education and general education classes at Valley City

State College, Mayville State Collego, North Dakota State

University, and the University of North Dakota. The sub­ jects ranged in age from eighteen to thirty-three years of age with a mean age of 19*38 years.

Phaso III of this study consisted of the con­ struction of norms for the proposed test for college age males. The Phase III subjects were administered one trial of the proposed test* The scores were placed in a 79 frequency distribution and tested for normality by use of

the chi-square test. Two norm tables were constructed:

(l) the Hull scale, and; (2) a five category descriptive scale.

Reliability and Validity of the Proposed Test

Twenty-nine of the eighty Phase XI subjects repeat­

ed the proposed trunk flexion strength-endurance test on a

later date to establish test reliability (0.9l). The

twenty-one Phase I subjects were tested on the proposed

test and during the same day the dynamic trunk flexion

strength test to establish validity (0 .83 ^). The eighty

Phase XX subjects were also given both the proposed test

and during the same day the criterion moasure, the dynamic

trunk flexion strength test, to further establish validity

(0.77).

Tho Proposed Trunk Flexion 5trength-Enduranco Test

The proposed test is an isotonic or dynamic

strength test of tho sit-up variety, which employs a spe­

cially constructed apparatus to secure the legs in an acute

flexed position and fix the pelvis in the posterior tilt

position. A belt designed to eliminate arm swing is also utilized in the administration of the test. This test is designed for use in a field testing situation for determin­

ing the fitness of tho abdominal muscle group of college

age males. 80

Test Administration, The only equipment required

for administration of the test is the proposed test appa­

ratus (Appendix B, Plate i). In the administration of the

test, the subject is placed in the supine position on the

test apparatus. His legs are flexed over the rod, which is

positioned approximately four inches below the popliteal

space (Appendix B, Plate III), and secured with a seat belt

across the ankles tightened so the subject's heels come in

contact with the backboard of the apparatus. The subject

is then instructed to grasp the sides and pull himself for­ ward until his buttocks comes in contact with the backboard, in this position tho lap belt is fastened securely to

stabilize the pelvis,

Aftor the subject is in the proper position, he is

instructed to place his arms through tho arm loops attached

to either side of the belt which has been previously placed about his torso immediately below the rib cage (Appendix B,

Plato IV), He is instructed to position the loops just above his elbows and to fold his arms placing his hands flat on the sides of his chest under his arms. The subject is now in tho starting position and ready to commence the test, Tho tost consists of curling-up so that both of the subject's arms come in contact with his quadriceps and re­ turning so that his head touches the base of the testing apparatus. This movement constitutes one repetition, the subject's score for this test is the maximum number of 81

repetitions that can be completed with no time limit; how­

ever, should the subject pause in the starting position for

longer than three seconds between repetitions his test is

terminated. Other special instructions that should be

given include: (l) both arms must touch the quadriceps

simultaneously; (2 ) the head must touch the base of the

apparatus after each repetition; (3 ) the trunk flexion

movement should bo deliberate and at a moderate rate to

eliminate body bounce and momentum as greatly as possible.

Conclusions

Within the limitations of this study and based upon

tho findings, the following conclusions are drawn:

1. Tho proposed trunk flexion strength-endurance

test is a valid and reliable strength-endurance measure of

the abdominal muscle group for college age males.

2. The proposed test is easy to administer, does

not require elaborate equipment, or considerable technical

s k ill.

3. Scoring is simple.

*+. The endurance factor is reduced to a minimum

in the proposed test, thus eliminating tho need for a time

limit in test administration.

5* Tho anthropometric measurements, height, sit­

ting height, and weight, have no bearing on a subject's performance in the proposed trunk flexion strength- 82

endurance test* the AAHPER two-minuto sit-up test, the

static trunk flexion strength test, or the dynamic trunk

flexion strength test,

6, The proposed test is superior to the two- minute sit-up test, administered as prescribed in tho

AAHPER Youth Fitness Test, as a test of abdominal muscle strength for college age males.

7. The sit-up movement, as performed in the pro­ posed tost, is dependent upon the abdominal muscles to a greater extent than the traditional sit-up. This con­ clusion is based on the premise that when the hips are flexed at an acute angle, as they are in the proposed test, it is more difficult for the hip flexors to take the place of the abdominals in the initial stage of the sit-up. Also when the action of the hip flexors is minimized more power is needed by the abdominal muscles to perform trunk flexion.

Relationship of the Findings to tho Stated Hypotheses

The findings of this study ga- ■’ support to the stated hypotheses. It was hypothesized that trunk flexions performed in the supine position, with the subjectfs hips floxed and his pelvis secured in tho posterior tilt position would be a valid and reliable strength-endurance test for muscles of the abdominal group. The intercor­ relations reported in Tables 8, and 13, indicated the pro­ posed test to be a valid and reliable test of strength- 83 endurance for tho muscles of the abdominal group. It was

hypothesized also that the anthropometric measures, height,

sitting height, and weight, would be insignificant factors

in the subject's performance of the proposed test. The

intercorrelations reported in Tables 8 and 13 indicated

that the anthropometric measurements were insignificant factors in performance not only on the proposed test, but on the criterion trunk flexion measures and the AAHPER two-minute sit-up test as well.

Recommendations

Tho following are recommendations for further study relative to the proposed trunk flexion strength-endurance tes t:

1. A validation study of the proposed test should be conducted using the Elgin Multiple Angle Testing unit as the criterion measure for trunk flexion strongth.

2. An electromyographic study should be conducted to determine the role of the various trunk muscles involved in the proposed test.

3. The Phase II and III portions of this study should be repeated with various age groups for both men and women.

h. The proposed tost should be employed exper­ imentally as a strengthening exercise,

5. The effect of waist girth on a subject's 8h performance of the proposed test should be studied. Al­ though waist girth was reported in the literature to be an insignificant factor in a subjects performance on movements of the sit-up variety, it was observed during Phase XII testing that abnormal waist girth was a possible factor in performance on the proposed test.

6. It is recommended that a study be conducted to determine the feasibility and validity of employing a bench in lieu of the proposed test apparatus for use in a mass testing situation. APPENDIX A

QUESTIONNAIRE

85 NAME: AGE: (Years)______(Months)

ADDRESS: (City)______(State)______PHONE:

TEAR & MAJOR IN COLLEGE: ______

HIGH SCHOOL ENROLLMENT: ______

I. HIGH SCHOOL ATHLETIC PARTICIPATION: (Check all varsity sports lettered in your senior year.)

F.B. Basketball Base B. Wrest, Track Other (list)

II. COLLEGE ATHLETIC PARTICIPATION: (Check all varsity sports participated in during the past year.)

F.B. Basketball Base B, Wrest. Track Other (list)

III. INDIVIDUAL WORK-OUT PATTERN OVER THE LAST THREE MONTHS: (Check area that most applies and briefly explain the activity.) 1. I have engaged in physical activity (exercise, in- tramurals, varsity sports, etc.) on an average of: five days per week. four days per week. three days per week. two days per week, one day per week, seldom, if ever. 2. Explain briefly the nature of the activity you participated in: ______

3. Have you been specifically exercising your abdom­ inal muscles? If so, briefly explain type of ex­ ercise and number of sots/reps done each exorcise day: ______APPENDIX B

PHOTOGRAPHS OF EXPERIMENTAL EQUIPMENT

87 PLATE I

PROPOSED TRUNK FLEXION STRENGTH-ENDURANCE TEST APPARATUS

88

PLATE II

PROPOSED TRUNK FLEXION STRENGTH-ENDURANCE TEST

90 91 PLATE XII

LEG ROD PLACEMENT

92

PLATE IV

BELT PLACEMENT

9^ 95 PLATE V

EXPERIMENTAL TEST - VARIATION II

96

PLATE VI

EXPERIMENTAL TEST - VARIATION III

98 99

r PLATE VII

STATIC TRUNK FLEXION STRENGTH TEST

100

PLATE VXIX

DYNAMIC TRUNK FLEXION STRENGTH TEST

102 103 APPENDIX C

TEST APPARATUS DIMENSIONS

10*1 ■£" Rod 10

20

Mloek under seat for 10 cm. incline ( M e a s u r e from base to bottom of seat) BIBLIOGRAPHY

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