Western Washington University Western CEDAR

WWU Honors Program Senior Projects WWU Graduate and Undergraduate Scholarship

Winter 2016

Study of the Effect of Hip Flexibility on Maximal Consumption and Stride Lenghth During an Incremental Treadmill Test in College-Aged Individuals

Kailey Barnette Western Washington University

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Recommended Citation Barnette, Kailey, "Study of the Effect of Hip Flexibility on Maximal Oxygen Consumption and Stride Lenghth During an Incremental Treadmill Test in College-Aged Individuals" (2016). WWU Honors Program Senior Projects. 10. https://cedar.wwu.edu/wwu_honors/10

This Project is brought to you for free and open access by the WWU Graduate and Undergraduate Scholarship at Western CEDAR. It has been accepted for inclusion in WWU Honors Program Senior Projects by an authorized administrator of Western CEDAR. For more information, please contact [email protected]. Honors Senior Thesis

Kailey Barnette Questions

– Is there any effect of hip flexor

flexibility on VO2 max in college-aged individuals?

– Is there any effect of hip flexor flexibility on stride length in college-aged individuals? Project Overview

– 10 male and 10 female college-aged subjects – All subjects were regular runners – Submaximal incremental treadmill test – Subjects ran on a pressure sensor treadmill in order to obtain stride length – Hip flexor flexibility was measured using the Modified Thomas Test and angles were measured with a digital inclinometer – Heart rate was obtained with a Polar Heart Rate Monitor – Data was analyzed in Excel with T-Tests, Pearson R Correlation Tests, and graphical representations Definitions

– VO2 max (maximal oxygen consumption, maximal oxygen uptake, maximal oxygen capacity): the maximum amount of oxygen the body can use during a specified period of usually intense that depends on body weight and the strength of the lungs – Modified Thomas Test: used to obtain measures of flexibility of hip flexor muscles (quadriceps muscles and iliopsoas); client sits at the very edge of the bench, then rolls back while pulling both knees to the chest, and releases one of the legs to the table and the angle femur at the hip is measured – Digital Inclinometer: electronic instrument used for measuring angles, slope, elevation, or depression Study Implications

– VO2 max is a universal indicator of aerobic fitness – Insight into whether hip flexor flexibility is beneficial or detrimental to runners’ – Insight into whether hip flexor stretching would be beneficial for runners – Improvements in running warm-ups, cool-downs and/or training regimens Background

– A.M. Jones study in 2002 – Measured running economy and sit-and-reach test performance in male international distance runners

– Used an incremental treadmill test to test VO2 max

– Found runners who performed worse on the sit-and-reach test had a higher VO2 max – Stated “it is possible that stiffer musculotendinous structures reduce the aerobic demand of submaximal running by facilitating a greater elastic energy return during the shortening phase of the stretch-shortening cycle” Background

– Linear relationship between heart rate and VO2 max – As an individual moves from a resting state to one of exercise, the body demands more oxygen for metabolic processes to keep up with the energy demands – Heart rate begins to steadily increase with exercise, allowing for faster oxygen delivery to the working tissue, such as skeletal muscle, which allows for an increase in oxygen consumption (VO2 max)

– The National Council on Strength and Fitness equation for estimated VO2 given heart rate was used to estimate VO2 Methods

– Participants signed the consent form, were weighed, their heights were measured, and were attached to the Polar Heart Rate Monitor – Participants sat in a chair for 5 minutes and their resting heart rate was measured – Participants ran a self-paced warm-up for 5 minutes (suggested to run anywhere between 5 and 6 mph) – Following the warm-up, the participants were taken to the treatment table and their hip flexor flexibility was measured with the Modified Thomas Test and Digital Inclinometer Methods

– Participants rested quietly in the chair for 2 minutes and were told the incremental running testing protocol – Participants attached the treadmill safety clip to their shirts and began running at 4.5 mph for 3 minutes; heart rate was recording during the last 30 seconds at this speed – After 3 minutes at 4.5 mph, the participants were instructed to increase the speed to 6.0 mph and ran for 3 minutes; heart rate was recording during the last 30 – After 3 minutes at 6.0 mph, the participants were instructed to increase the speed to 8.5 mph and ran for 3 minutes; heart rate was recording during the last 30 seconds at this speed – Stride length was recorded at 8.5 mph Methods

– Following completion of the test, the participants were instructed to actively cool down on the treadmill at their own pace for 5 minutes (suggested to cool down at approximately 3.5 mph) – Each of the participants’ stride lengths were normalized by dividing by their heights

– Each of the participants’ maximal heart rate (correlated with VO2 max) was calculated by the Age-Predicted Maximal Heart Rate Formula (HRmax=220-Age) – Their heart rate obtained while running at 8.5 mph was divided by their APMHR and was converted to a percentage

– Oxygen consumption (VO2) at 8.5 mph was calculated via the predetermined formula

– VO2 max was calculated given percentage of heart rate and the calculated VO2

– Absolute Relative VO2 max was calculated by normalizing VO2 by weight Results

Comparison of Right Hip Flexor Flexibility and Comparison of Left Hip Flexor Flexibility and Relative Relative VO2 max in Male Participants VO2 max in Male Participants 65 65

60 60

55 55

50 (mL/kg/min) 50

(mL/kg/min)

max 2 2 45 max 2 45

40 40 Relative Relative VO 35 Relative VO 35

30 30 165 170 175 180 185 190 195 200 160 165 170 175 180 185 190 195 Hip Flexibility (degrees) Hip Flexibility (degrees)

R-Value: 0.48; moderate positive relationship R-Value: 0.61; moderate positive relationship Results

Comparison of Right Hip Flexor Flexibility and ComparisonComparison ofof LeftLeft HipHip FlexorFlexor FlexibilityFlexibility andand RelativeRelative Relative VO2MaxVO2 max in inFemale Male Participants VO2MaxVO2 max in inFemale Male Participants 6580 6580 75 75 60 60 70 70 6555 5565 60 60

50 (mL/kg/min) 50

(mL/kg/min) 55 55 2 2 max

2 2 max 5045 4550 Relative Relative Max VO2 Relative Relative Max VO2 4045 4045 40 40

35 Relative VO 35 Relative Relative VO 35 35 30 3030 165 170 175 180 185 190 195 200 160160 165165 170 170 175 175180 185180 190185 195 190200 195205 Hip FlexibilityHip Flexibility (degrees) Hip FlexibilityHip Flexibility (degrees)

R-Value: 0.70; strong positive relationship R-Value: 0.83; strong positive relationship Results

Comparison of Right Hip Flexor Flexibility and ComparisonComparisonComparison ofof LeftLeft of LeftHipHip FlexorFlexorHip Flexor FlexibilityFlexibility Flexibility andand andRelativeRelative NormalizedRelativeRelative VO2MaxStride VO2Max Length in in Female Male in Male Participants Participants Participants NormalizedVO2MaxVO2Max Stride in in Length Female Male Participantsin Participants Male Participants 65801.7 65801.7

75 75

less) less) - - 601.65 1.6560 70 70 1.6 1.6 6555 5565 601.55 1.5560 50 50 551.5 551.5 45 45

Relative Relative Max VO2 1.4550 1.4550

Length (cm/cm Length(cm/cm or unit Length(cm/cm or unit

Relative Relative Max VO2 Relative Max VO2 Relative Relative Max VO2 4045 4045 1.4 1.4 40 40 35 35 351.35 1.3535 301.3 30301.3 165165 170170 175175 180180 185185 190190 195195 200 160160160 165165165 170 170170175 175175180 185180180 190185185 195 190200 195205

Hip FlexibilityHip Flexibility (degrees) Hip FlexibilityHipHip FlexibilityFlexibility (degrees)

Normalized Stride Normalized Stride

R-Value: -0.55; moderate negative relationship R-Value: -0.62; moderate negative relationship Results

Comparison of Right Hip Flexor Flexibility and ComparisonComparisonComparison ofof LeftLeft of LeftHipHip FlexorFlexorHip Flexor FlexibilityFlexibility Flexibility andand andRelativeRelative NormalizedNormalizedRelativeRelative Stride VO2MaxStride VO2Max Length Length in in Female Malein in Female Male Participants Participants Participants Participants NormalizedNormalizedVO2MaxVO2Max Stride Stride in Lengthin Length Female Male in Participantsin ParticipantsFemale Male Participants Participants 1.7565801.7 1.7565801.7

75 75

less) less) - - 601.651.7 1.65601.7 70 70 1.6 1.6 1.656555 1.655565 601.55 1.5560 501.6 501.6 551.5 551.5 1.5545 1.5545

Relative Relative Max VO2 1.4550 1.4550

Length (cm/cm Length(cm/cm or unit Length(cm/cm or unit

Relative Relative Max VO2 Relative Max VO2 Relative Relative Max VO2 40451.5 40451.5

1.4 1.4 Normalized StrideLength Normalized StrideLength 40 40 1.4535 1.4535 351.35 1.3535 301.41.3 30301.41.3 165165165 170170170 175175 180180 185185 190190 195195 200 160160155160 160165165165 165170 170170170175 175175175180 180 185180180185 190190185185 195195 190200200 195205

Hip FlexibilityHipHip Flexibility Flexibility (degrees) Hip FlexibilityHipHipHip Flexibility FlexibilityFlexibility (degrees)

Normalized Stride Normalized Stride

R-Value: -0.39; weak negative relationship R-Value: -0.22; weak negative relationship Results

ComparisonComparison of Normalized of Right Hip Stride Flexor Length Flexibility and Relativeand ComparisonComparison ofof NormalizedLeft Hip Flexor Stride Flexibility Length andand RelativeRelative RelativeVO 2VO2Max max in Male in MaleParticipants Participants VOVO2Max2 max in inFemale Male Participants

651.7 651.75 less)

less) 1.7 - - 601.65 60 1.6 1.65 55 55 1.6 1.55 50 1.5550 1.5 45 451.5 1.45

1.45

Length (cm/cm Length(cm/cm or unit Relative Relative Max VO2 Relative Relative Max VO2 40 40 1.4 1.4 35 35 1.35 1.35 301.3 301.3 16530 17035 17540 18045 18550 19055 19560 20065 16040 16545 50170 55175 60 180 65 185 70 19075 19580

RelativeHip VO Flexibility2 max (mL/kg/min) RelativeHip VO Flexibility2 max (mL/kg/min)

Normalized StrideLength (cm/cm or unit Normalized Stride

R-Value: -0.10; weak/no relationship R-Value: -0.18; weak/no relationship Analysis

– T-Tests were run to analyze the statistical significance of the differences between the male and female populations

– Men and Women’s Relative VO2 max: 0.0060 – Men and Women’s Right Hip Flexibility: 0.794 – Men and Women’s Left Hip Flexibility: 0.410 – Men and Women’s Standardized Stride Lengths: 0.0143 Interpretations

– The P-Values calculated when comparing the male and female participants show that the drastic differences between male and female VO2 max and stride length scores were statistically significant – The R-values comparing the female participants’ right and left hip flexor flexibility to their relative VO2 max scores demonstrate that there is a strong

correlation between hip flexor flexibility and VO2 max Interpretations

– Dissimilar to the study by A.M. Jones, this study did not find limited flexibility improved relative VO2 max – Otherwise, there were no significant correlations between any of the other variables – There were statistically significant differences between the male and female participants in stride length and relative VO2 max

– The average relative VO2 max score for males was 43.36 mL/kg/min, while the average relative VO2 max score for females was 56.43 mL/kg/min – The average male stride length was 1.48, while the average female stride length was 1.59 Interpretations

– The average relative VO2 max for college-aged sedentary females is 33 ml/kg/min, while the average relative VO2 max for college-aged sedentary males is 42 ml/kg/min (Bouchard 1998)

– The average relative VO2 max for college-aged elite female athletes is around 70 ml/kg/min, while the average relative VO2 max for college-aged elite male athletes is around 82 ml/kg/min (Pate et al. 1987) – The average maximal oxygen consumption for female college-aged recreational runners is around 55-60 ml/kg/min, while the average for college-aged male recreational runners is around 67-72 ml/kg/min – The males that participated in this study averaged much lower than the national average for the same population, while the females were right around the national average for the female population

– The significant statistical difference between the male and female VO2 max scores could possibly be due to the inaccurate and disproportionate fitness level of the male participants in this study Discussion

– Given the small population this study tested and the possible unequal fitness levels between the male and female populations, the results are inconclusive and simply present some correlation

– The strong positive correlation between the female participants’ VO2 max scores and both the right and left hip flexor flexibility did not support this study’s hypothesis – This study’s hypothesis was based on the relationship between men’s hamstring flexibility and VO2 max scores – Further research should be done to assess any gender differences between flexibility and relative VO2 max Future Research

– Study only looking at competitive female runners’ hip flexor flexibility and VO2

max – Study of varying levels of (non-runner, recreational runner, and elite runner) and a comparison of VO2 max and hip flexor flexibility – Study looking at any differences between sprinters and distance runners – Study using a metabolic cart and maximal tests Thank you

– Thank you to Dr. San Juan for advising and overseeing this research – Thank you to all 20 of the participants – Thank you to Donnelly Miller and the Kinesiology Graduate Students who assisted in testing – Thank you to the Kinesiology Department and Honors Program for providing the opportunity and resources to conduct this study