Review Article

Injuries Associated with Current Dance-Exercise Practices

Michele R. Scharff-Olson, Ph.D., FACSM, Henry N. Williford, Ed.D., FACSM, and Jennifer A. Brown, Ed.D.

Abstract Dance-exercise instructors should also that have received attention in injury he evolution of dance-exercise is be aware that because of their increased studies. Some factors such as training broad and includes the develop- exposure they are at increased risk for frequency, training volume, previous Tment of specific modes such as health problems associated with dance- injury history, and instructor status low-impact variants and step aerobics. exercise regimens. have clearly been validated as pos- Injury studies clearly show that injury sessing a causative role while other rates, patterns, severity, and risk factors are hroughout much of the factors continue to be viewed more modality-specific. High-impact aerobics, 1980s the predominant form tentatively.1,3-5 first shown to elicit a substantial rate of of dance-exercise was “high- As the styles of dance-exercise have injuries, results largely in lower extremity T impact” aerobics. Though quite popu- continued to evolve during the 1990s, conditions which are primarily due to lar, research showed that participation overuse and training errors. In contract, so has the methodology employed by in high-impact aerobic dance pro- researchers in injury investigations. low-impact dance-exercise can produce duced a rather alarming rate of mus- more severe upper body conditions. The For example, the early high-impact culoskeletal problems, particularly injury studies were largely a report- advent of more recent activities, such as 1 step aerobics and slideboard exercise, yield among instructors. In response to its ing of injury occurrence.1 Little injury rates that are quite low. However, injurious nature, a number of lower information about the actual nature 2-4 these modes tend to produce significant impact styles soon evolved. These and severity of the musculoskel- rates of Grade I and Grade II delayed more current forms include “low-im- etal problems was known. Therefore, onset muscle soreness in the calf and me- pact dance-exercise,” “step aerobics,” investigations on contemporary dial thigh regions. Exercise progression, and “choreographed lateral motion dance-exercise modes have increas- symptom monitoring, and one-on-one training” (i.e., “slideboard exercise”). ingly documented injury severity via instruction provided to new participants Table 1 provides a summary of various can help to reduce the risks for injury. rating scales. Table 2 shows a severity dance-exercise training characteristics rating scale that was employed in a very recent step aerobics study.2 The Michele R. Scharff-Olson, Ph.D., FACSM, is an Associate Professor in the results of this study demonstrated that Department of Physical Education and the Research Administrator for Human a high percentage of the participants Performance Studies at Auburn University Montgomery, Montgomery, Alabama. experienced problems. However, the Henry N. Williford, Ed.D., FACSM, holds the title of Distinguished Research majority of the reported conditions Professor at Auburn University Montgomery. He is the Director of the Human were relatively minor; largely Grade I Performance Laboratory, the Chairman of the University Research Council, and in severity. Many scientists now assert a Professor in the Department of Physical Education. that Grade I problems are more ap- propriately cataloged as “complaints” Jennifer A. Brown, Ed.D., is the Department Chair of Physical Education (versus “injuries”) since they do not at Auburn University Montgomery. She is also a member of the University curtail training or require medical Graduate Council and currently serves as Executive Director of the Alabama State 3,4 Association for Health, Physical Education, Recreation, and Dance. evaluation. Thus, the likelihood of sustaining musculoskeletal injuries Correspondence and reprint requests: Michele R. Scharff-Olson, Ph.D., FACSM, of a serious classification may prove Auburn University Montgomery, Human Performance Laboratory, Department minimal with current dance-exercise of Physical Education, P.O. Box 244023, Montgomery, AL 36124-3023. styles such as step aerobics.3

144 Journal of Dance Medicine & Science Volume 3, Number 4 1999 145

Table 1 Dance-Exercise Injury Risk Factors cates that the low-impact style causes fewer musculoskeletal problems.9,10-12 Validity as a Factor Causative Risk Factor For example, one study found a 14% greater risk of injury for high-impact Age Not established versus for low-impact dance-exer- Floor Surface Not clear cise.10 Another investigation revealed Footwear Not clear Frequency of Participation Established that low-impact aerobic dance had the Impact Style Established lowest injury rate compared to three Increased Training Volume Established other styles: high-impact, step aero- Instructor Status Established* bics, and “funk” aerobics.11 Both of Pre-Participation Orientation Likely these studies matched either the train- Prior Injury Established ing program with respect to exercise Sex Not established volume or equated the injury rates in Technique Monitoring Likely terms of participation/exposure time. *Assumed to be a function of the higher exposure rates for instructors versus students (i.e., With few exceptions, the severity higher training frequency and time at risk due to teaching schedules). of injuries also appears to be less for the low-impact style9,10 as does the rate of acute injury (34% for high-impact Table 2 Severity Rating Scale Employed in Recent Dance-Exercise Injury versus 20% for low-impact9). Figure Studies* 1B illustrates the mean severity ratings Severity Category Description between the two styles. The shin area, Grade I Problem resulting in pain/discomfort but is not altering daily in particular, tends to experience a no- activity patterns or exercise participation. tably higher injury severity from high- Grade II ¶ Problem of such magnitude that it is resulting in some altera- impact dance-exercise. However, the tion or modification in exercise participation. shoulder region appears to incur both Grade III ¶ Problem resulting in alteration of daily activity patterns as well a higher rate and severity of injury as exercise participation. from lower impact styles.3,12 The dif- Grade IV ¶ Problem resulting in a need for medical care. ferences in injury patterns between the *Employed in studies by Williford and colleagues.3,4 ¶Yield “time losses” in training. high-impact and lower-impact styles are generally attributed to the greater repetitive impact encountered by the Other, and perhaps, more hazard- High Versus Low Impact lower extremities from high-impact ous health and injury-related condi- Dance-Exercise Injuries versus the increased emphasis on up- tions specific to the dance-exercise As previously noted, the major im- per body choreography employed by teacher have also been unveiled in the petus for the development of lower the lower-impact variants.2,3 Another recent literature.6,7 As cited in Table 1, impact dance-exercise formats was distinction between high-impact and previous studies found that instructors the concern ignited by the high injury low-impact dance-exercise injuries experienced a higher incidence of rate reported for high-impact aerobic concerns the time during which prob- musculoskeletal problems compared dance in the early 1980s.1 The first lematic conditions persist. Specifically, to their students.1,8 However, eating variant, “low-impact” aerobic dance, one study found that the average disorders and vocal injuries are two quickly became quite popular.2 Low- duration of a low-impact musculo- recently documented conditions impact aerobic dance is performed in skeletal problem was 2.8 weeks versus that may also be extremely common a manner similar to its high-impact 4.5 weeks for high-impact aerobic among dance-exercise teachers.6,7 In predecessor (i.e., is rhythmically dance.9 Thus, the research shows that light of these current issues, research- choreographed to music), however, low-impact dance-exercise is a viable ers are presently attempting not only the major distinction is that the par- form of cardiovascular training which, to clarify the musculoskeletal injury ticipants are instructed to temper any when compared to the high-impact mechanisms associated with lower movements that would traditionally style, yields a lower (overall) injury impact dance-exercise styles, they are require them to become “airborne.” rate and a briefer time interval dur- also focusing on those factors that For example, jogging is modified and ing which symptoms are experienced place instructors at risk for other sig- performed as marching; skipping-like (though the chance of sustaining nificant health conditions. Therefore, movements require the same limb Grade II problems in the upper body the objectives of the remainder of translation but are executed without may be increased with lower-impact this article are to provide an updated a bounding phase. formats). dance-exercise injury review including As shown in Figure 1, comparative It should also be noted that the an overview of health risks specific to injury data between high and low- lower-impact styles might not be instructors. impact aerobic dance generally indi- principally protective with respect to 146 Journal of Dance Medicine & Science Volume 3, Number 4 1999

High Versus Low Impact Comparative Injury Data prehensive training investigation that measured changes in aerobic power (cardiovascular fitness), body compo-

Impact sition, and injury status was recently 80 3 IV Impact reported in the professional literature. High

Low The study was conducted with adult Impact Shin Impact college students who participated in 60 III Low Impact

Impact a step exercise protocol that was mod- High Impact Shoulder Shin High eled after the Step Reebok program. Low

High During the 10-week training 40 II Impact Ankle Shoulder period, all participants completed a Ankle

Low questionnaire at each class meeting.

20 I The questionnaire required a detailed

Risk of Injury (percent) reporting of injury symptoms and Mean Severity Rating anatomical sites. A high rate of com- plaints was reported during the first Figure 1 Low-impact dance aerobics poses a lower risk of injury compared to high- two weeks of the training program impact. However, the two styles have different injury patterns and low-impact may but the problems were relatively low result in relatively more severe upper body complaints. in severity. Specifically, 66% of the participants reported Grade I com- Anatomic Patterns of Step Aerobic Injuries 3 plaints and 8% reported Grade II conditions. No Grade III or IV injury 40 was reported and only one partici-

35 pant reported having to dramatically decrease the intensity of her training Thigh Hip Neck 30 Ankle performance on just one occasion due Shin Shoulder Calf Knee Back to significant lower leg pain. A follow- ted Injuries 25 up analysis of the Grade I complaints revealed that the participants were 20 experiencing delayed onset muscle soreness (DOMS) during the initial 15 stage of the training program. By the 10 third week, no problems (of any sever- centage of Repor

r ity) were reported.

Pe 5 A second training study found that, on average, just 0.4 days of Calf and Shoulder had highest rate of Grade I and II complaints (43%). participation were lost due to injury 14 Other sites had Grade I or II injury rates between 4% to 26%. from step training. No participants in either training study experienced Figure 2 Step aerobics yields a high rate of Grade I and Grade II DOMS in the calf problems of a magnitude requiring and shoulder regions during the initial two weeks of step training. Other anatomical them to discontinue participation in sites experience very low rates of Grade I or Grade II conditions. the program.3,14 In addition, a third prospectively-designed investigation13 prior injuries. For instance, regardless specifically, teachers should person- conducted with fitness facilities found of the specific dance-exercise style, ally familiarize clients with appropri- that step aerobics yielded only 6.0 studies have found that participants ate movement techniques and also injuries per 1,000 hours of participa- with a history of injury are twice as encourage “at-risk” individuals (i.e., tion. In contrast, the injury rate for likely to experience re-injury.13 Dance- those with an injury history) to prog- those participating in running regi- exercise teachers should be aware of ress slowly in terms of both intensity mens was notably higher: 14.7 injuries the differences between high-impact and volume of participation. occurred during the same 1,000 hours and low-impact aerobic dance in of participation. terms of injury incidence, severity, Step Aerobics Injuries Figure 2 shows the injury rate as- and anatomical patterns. In addition, Few large scale step aerobics studies sociated with various anatomical sites they should also monitor and guide have focused on injuries.3,11 Unfor- for the first study.3 In contrast to the students who have a prior history tunately, many sources of injury data high incidence of anterior lower leg of injury since these participants are are also available only in abstracted (shin) problems reported for high- more likely to sustain injury. More form.11-14 However, one rather com- impact and low-impact aerobics, Journal of Dance Medicine & Science Volume 3, Number 4 1999 147

Table 3 Selected Injury Patterns Reported for Choreographed Lateral This study was conducted at Au- Motion Training burn University and the design was nearly identical to the one used in First Week of Training Second Week of Training Site Grade I Grade II Grade I Grade II the previously reviewed step aerobics training investigation. The subjects Hip N = 2 (7%) N = 2 (13%) N = 1 (6%) participated in a 10 week, progres- Inner Thigh N = 12 (45%) N = 6 (38%) N = 6 (35%) sively graded, lateral motion exercise Knee N = 8 (29%) N = 8 (50%) N = 7 (41%) N = 2 (100%) Shin N = 4 (14%) N = 1 (6%) program and completed detailed questionnaires concerning muscu- Top four reported injury sites. Two or fewer complaints were reported for ankle, calf, foot, and shoulder. No Grade III or IV injuries were reported during initial training. By week three, loskeletal problems and injuries at no complaints were reported. each class meeting. Table 3 shows the anatomical patterns and severity of the greatest number of complaints es for new and/or very low-fit clients injuries across the initial two weeks of resulting from step aerobics occurred so that they may be properly oriented training. Grade I and II injuries of the in the posterior lower leg (calf). Also, and more closely monitored. How- inner thigh and knee were the most since step aerobics is a lower impact ever, in most commercial settings, common complaints. The overall form of dance-exercise, a wide array logistics are such that the beginning incidence of injury by severity rating of upper body and arm choreography participant is assimilated into classes was 80% for Grade I complaints, 52% is incorporated into the workout. with experienced exercisers and may for Grade II problems, and 0% for Therefore, like low-impact aerobic receive only brief pre-participation Grade III. One subject experienced a dance, step aerobics appears to yield instruction. Furthermore, the group Grade IV problem that was related to a greater incidence of documented nature of the activity (i.e., one teacher a pre-existing condition. Specifically, shoulder problems (see Figs 1B and and 40 students) can easily preclude the subject re-injured her right plica 2). Regardless, though, of the high one-on-one monitoring of exercise in- and received medical care. frequency reporting for calf and shoul- tensity among the participants. While A comparison of the injury severity der complaints, it is very important to relatively low in occurrence rate, the from this activity to other low-impact remember that these problems were “time loss” injuries documented in dance-exercise styles shows that the primarily Grade I in severity (only the study conducted with fitness majority of injuries are similarly mi- 8% were Grade II). Again, no Grade facilities13 supports the need for in- nor (Grade I or II) and resolve within III or IV injuries were reported by the dividualized progression and student two weeks. Like step aerobics, DOMS participants during the 10-week step monitoring. “Time loss” injuries are was also the primary mechanism for training program. more severe than Grade I complaints the documented problems. However, The nature of the step aerobics pro- because they do cause intermittent the overall rate of more severe Grade II gram may be a key factor in decreasing cessation of training. Therefore, DOMS was notably higher from lat- injury potential.3 In the first study,3 aerobic step exercise teachers should eral motion training (52%) compared the step aerobics program was led strongly consider adopting some of to step aerobics dance training (just by a highly educated instructor who the instructional practices that have 8%4). In practical terms, DOMS in possessed seven years of experience been employed in college and uni- the medial leg musculature from lat- as a certified step aerobics instructor versity training studies since these eral motion exercise can have a greater and held a master’s degree in exercise practices are associated with a very low impact on a participant’s performance kinesiology. The participants also rate of participant injury and minimal compared to the DOMS commonly followed a well-controlled, graded “time loss” injuries.3,14 As noted pre- experienced in the calf and shoulder training protocol (i.e., the initial viously, injury prevention strategies regions from step aerobics. The Grade exercise sessions were shorter in du- include pre-participation orientation, II severity of injury in the Auburn ration, of lower intensity, performed individualized technique monitoring, University study4 caused many sub- on lower platform heights, and the and moderate progressions in training jects to markedly modify the way music tempo was 122 to 124 beats per intensity and volume. Furthermore, in which they performed the lateral minute). During classes, the exercise to prevent drop-out, teachers should motion movements (e.g., at slower intensity was closely and individually caution new students that DOMS, a speeds, for shorter durations, with monitored with each student record- common side effect of step aerobics, is less range of motion). Some students ing their prescribed heart rate at desig- not an actual injury, and thus, should also had to episodically cease class nated intervals. Throughout the entire not foil continued participation. participation (i.e., “sit out” from time training period, the subjects also to time) during the first two weeks of received lecture-oriented instruction Choreographed Lateral Motion training.4 concerning appropriate step exercise Injuries Choreographed lateral motion techniques and mechanics. Only one study has analyzed inju- training is an activity that primarily Some clubs and studios offer sepa- ries associated with choreographed requires abduction and adduction of rate “introductory” step aerobics class- lateral motion (slideboard) training.4 the legs. In contrast, the majority of 148 Journal of Dance Medicine & Science Volume 3, Number 4 1999

9 Time Loss Injury Rates for Popular Activities 13 ning. Therefore, the contemporary lower 16 impact forms of dance-exercise (low- impact aerobic dance, step aerobics, 14 and choreographed lateral motion Sports

Sports training) appear to present a signifi- 12 Running cantly reduced risk of injury compared Activities to high-impact dance-exercise and

10 Individual many popular competitive sports Competitive Exercise Fitness including running.3,4,9,14 More specifi- 8 cally, the injury risk of current dance-

Aerobic exercise styles is similar to other highly Resistance popular low-impact and non-impact 6 activities such as cycling, weight train-

7 ing, stair exercise, and racewalking 4 3 to (Fig. 3). Time Loss per 1000 Hours Participation Health and Injury Issues 2 Among Dance-Exercise Instructors High Risk of Injury As noted previously, instructors tend High-Moderate Risk of Injury to experience a higher incidence of musculoskeletal injuries compared to Low to Moderate Risk of Injury their students.1 Since dance-exercise Figure 3 Aerobic dance/aerobic fitness activities generally present a low to low-moderate teachers instruct classes at frequencies risk of time loss injuries compared to other popular sport activities and running. that often exceed the participation rate of students, the elevated injury incidence for instructors is attributed popular cardiovascular activities such extensions. to their greater exposure time. For as jogging, cycling, and step aerobics instance, dance-exercise instructors require anterior-posterior movement Injuries Associated with Other may teach as many as 13 hours per of the legs.14 Common lifestyle move- Popular Forms of Conditioning week.1,8 More specifically, 25% of ments are also executed largely in the When compared to other activities, instructors have reported teaching anterior-posterior plane (e.g., walk- the low-impact dance-exercise modes more than 10 classes a week while ing, sitting/standing, climbing stairs). pose a low-moderate potential for seri- only about 5% of participants take as Therefore, the rather novel lateral ous injury. For instance, a recent pro- many as 10 classes in a 7 day period.8 motion maneuvers can be expected to spective study shows that dance-based Dance-exercise teachers may also elicit a high rate of Grade II DOMS aerobic activities, cycle exercise, and ignore their symptoms and persist in in the medial thigh and knee regions. step climbing (collectively classified teaching despite experiencing muscu- Additionally, the eccentric activity as aerobic fitness activities), yielded loskeletal discomfort.5 Participating of the medial leg muscles, which are a moderately low risk for producing when symptoms are present has been used to decelerate the exerciser during injuries that required a cessation of established as a risk factor for develop- every lateral movement cycle, may be participation; they produced between ing an overuse injury.15 the specific mechanism for the pro- just 3 to 7 “time loss” injuries per In the past, a large percentage nounced degree of muscle soreness.4 1,000 hours of participation.13 This (nearly half of exercise instructors Dance-exercise professionals and/or injury risk is clearly lower than that surveyed) also disclosed that they other fitness trainers who introduce for more vigorous sports and aerobic had no formal training in teaching lateral motion exercise to clients as activities such as running. Specifically, dance-exercise and were often self- a means of aerobic stimulation, may one 8-week training study that com- taught.1 Experienced teachers possess- want to consider incorporating some pared injury rates between low-impact ing activity-specific certifications or anterior-posterior movement patterns aerobic dance and running showed formal training in physical education if DOMS is limiting the normal in- that low-impact aerobics resulted and exercise kinesiology have been tensity or duration of the participant’s in significantly fewer injuries and associated with programs that yield workout. Some of these alternative lost training/performance time.11 In very low rates of critical injuries.3,4,9 maneuvers include simulating the contrast, an earlier study found that Therefore, more moderate teaching cross-country skiing movement and high-impact aerobic dance produced and participation frequencies, at- performing alternate single rear leg a greater injury incidence than run- tention to symptoms, and increased Journal of Dance Medicine & Science Volume 3, Number 4 1999 149

Table 4 Factors Involved in Vocal “Injuries” in Group Exercise Leaders fitness with thinness is speculated to have a profound influence on the Factor Significance* dance-exercise teacher since she is con- Alterations in Sleep Patterns Significant sidered the role model for the fitness Career Duration (years of instruction) Significant aesthetic.7 One recent investigation7 Changes in Activity Levels Significant found that 40% of dance-exercise Cueing (shouting to cue) Highly Significant Facility (size and acoustics) Not Significant leaders reported a history of eating Frequency of Vocalization Highly Significant disorders. Bulimia was more com- Microphone Use Not Significant mon (23%) than anorexia (17%). The Music Volume Low Significance results also showed that the teachers Variability in Weather Significant scored similarly to anorectic groups on Voice Hygiene Knowledge Low Significance measures of “Body Dissatisfaction,” *Only the significant and highly significant factors possessed a robust association with voice “Drive for Thinness,” “Perfection- problems (at least a > 0.95 degree of statistical certainty5). ism,” and “Ineffectiveness.” In gen- eral, the cohort of teachers exhibited behavioral characteristics that are education are goals that dance-exercise proper use of microphones and sound consistent with having preoccupa- instructors should continue to under- systems in order to maximize any tions over body weight, body shape, take in order to reduce injury risk not protective benefit from this technol- and eating. Common psychological only to participants but to themselves. ogy.6 In other words, they may need traits related to “Perfectionism” and instruction similar to that received “Ineffectiveness” included concerns Professional Voice Disorders (and practiced by) performers such over “doing better,” “performing bet- A problem unique to dance-exercise as singers and public speakers. They ter,” and “achieving more,” as well instructors, and not especially evident should also acquaint themselves with as perceptions of “inadequacy.” The in other forms of dance, has been the the more current information re- alarming statistics associated with this recent reports of voice disorders.6,16 garding vocal injury risk factors and report have clearly pointed to the need Over 40% of instructors surveyed attempt to become more disciplined for increased research in this area. in separate studies report experienc- in applying vocal hygiene techniques. Interestingly, exercise participation ing vocal aberrancies from teaching, Moreover, it has been suggested that is now regarded as an independent risk including hoarseness and associated microphone and vocal hygiene edu- factor for eating disorders.18 Thus, sore throat.6,17 Voice loss, either partial cation be included as a formal com- exercise teachers may be at a particu- or complete, is also common and can ponent of the instructor preparation larly heightened risk for developing occur during or immediately follow- (certification) process.6 dysfunctional eating behaviors since ing a dance-exercise class.6 Instructors The fact that dance-exercise teach- exercise instruction requires very who repeatedly raise their voices to ers are performers should also be un- high rates of exercise participation. cue classes and/or who teach at higher derscored. During instruction teachers As noted, the unique nature of eating frequencies are at the greatest risk for participate, generally without pause, disorder risks among many exercise this condition. in modeling all of the dance-exercise instructors clearly indicates a need for The mechanism for voice injuries choreography. As noted, this level further scientific study. is the collision force of the vocal folds of physical exertion, coupled with Conclusions during vocal projection. Dance-exer- high teaching frequencies, increases cise instructors also physically exert their risk for both musculoskeletal During the last 10 years, integrated themselves when vocalizing instruc- and vocal problems (see Tables 2 and efforts from dance-exercise teachers, tions to class participants. Projecting 4). Circulating throughout the class, researchers, and instructor training loudly while physically performing providing individualized corrective organizations have resulted in better increases the collision force of the feedback are instructional alternatives clarifying the nature of dance-exer- vocal folds, which, in turn, increases that can allow the teacher to lessen cise injuries. Recent studies, which the likelihood of vocal fold trauma.6 both their physical and vocal exertion provide detailed analyses of injury Interestingly, however, microphone during classes. severity, mechanisms, and anatomical usage and familiarity with other vocal sites, have clarified distinctive injury hygiene techniques is not associated Secondary Health Concerns patterns among the various styles and with protection against incurring Aside from musculoskeletal and vocal show that the more current, lower- voice problems. Table 4 shows various problems, instructors also appear to be impact variants generally yield a low factors that have been analyzed and at risk for health-related conditions of to low-moderate risk of injury. The denotes those that pose a significant a more psychological nature, specifi- greater availability of low-impact risk of vocal trauma. cally, eating disorders. The contem- formats coupled with improved in- Dance-exercise instructors may be porary societal perspective that pairs struction are specific factors associated in need of formal training concerning 150 Journal of Dance Medicine & Science Volume 3, Number 4 1999 with injury protection. Monitoring 7. Scharff-Olson M, Williford HN, Phys Sportsmed 13:114-120, 1985. students with a prior history of injury Richards LA, Brown JA, Pugh S: 16. Heidel SE, Torgerson JK: Vocal and encouraging a moderation in ac- Self-reports on the eating disorder problems among aerobic instructors tivity patterns when symptoms occur inventory by female aerobic and aerobic participants. J Speech are other significant measures that instructors. Percept Motor Skills Hearing Dis 27:147-151, 1993. 82:1051-1058, 1996. 17. Komura Y, Inaba R, Fujita S, et al: teachers can undertake in providing 8. Mutoh Y, Sawai S, Takanashi Y, Health condition of female aerobic exercise enthusiasts with dance-based Skurko LL: Aerobic dance injuries dance instructors. Japan J Industrial activities that effectively promote among instructors and students. Phys Health 34:326-334, 1992. cardiovascular fitness and pose a low Sportsmed 16:81-86, 1988. 18. Davis CS, Kennedy SH, Ravelski risk of injury. Research concerning 9. Harnischfeger H, Raymond C, E, et al: Obsessive compulsiveness the prevention of health risks unique Hagerman C, Dickinson A, et al: and physical activity in anorexia to dance-exercise teachers will also Incidence of injury following high nervosa and high-level exercising. continue to be important throughout and low-impact aerobics versus J Psychosom Res 39(8):967-976, this and future decades. running. Med Sci Sports Exerc 1995. 20(2):S-88, 1988. References 10. Janis LR: Aerobic dance survey: A Further Reading 1. Francis LL, Francis R, Welshons- study of high-impact versus low- 1. Darby LA, Browder KD, Reeves BD: Smith K: Aerobic dance injuries: A impact injuries. J Am Podiatr Med The effects of cadence, impact and survey of instructors. Phys Sportsmed Assn 80:419-423, 1990. step on physiological responses to 13(2):105-111, 1985. 11. Requa RK, Garrick JG: Injuries in aerobic dance exercise. Res Quarterly 2. Koszuta LE: Low-impact aerobics: various forms of aerobic dance. Med Exerc Sport 66(3):231-238, 1995. Better than traditional aerobic dance? Sci Sports Exerc 25:S-49, 1994. 2. Kravitz L, Heyward VH, Stolarczyk Phys Sportsmed 14:156-161, 1986. 12. Scharff-Olson M, Williford HN, LM, Wilmerding V: Does step 3. Williford HN, Richards LA, Scharff- Wang N: Injury patterns and exercise with hand weights enhance Olson M, Blessing DL, et al: Injury severity among aerobic dance modes. training effects? J Strength Condition rates and physiological changes Presented at the Southeast ACSM Res 11(3):194-199, 1997. associated with bench stepping and Conference, Chattanooga, Tennesee, 3. Scharff-Olson M, Williford running in women. J Sports Med January 1996. HN, Blessing DL, Brown J: The Phys Fit 38(3):221-226, 1998. 13. Requa RK, DeAvilla LN, Garrick JG: physiological effects of bench/step 4. Williford HN, Blessing DL, Scharff- Adult recreational fitness injuries. exercise. Sports Med 21(3):164-175, Olson M, Brown JA: Injury rates and Med Sci Sports Exerc 24:S-144, 1996. physiological changes associated with 1992. 4. Scharff-Olson M, Williford HN, lateral motion training in females. Int 14. Byrnes WC, McCullough P, Blessing DL, Moses R, Wang T: J Sports Med 17(6):452-457, 1996. Dickinson A, Noble J: Incidence and Vertical impact forces during bench- 5. Garrick JG, Gillen DM, Whiteside severity of injury following aerobic step aerobics: Exercise rate and P: The epidemiology of aerobic training programs emphasizing experience. Perceptual Motor Skills dance injuries. Am J Sports Med running, race walking, or step 84:267-274, 1997. 14:67-72, 1986. aerobics. Med Sci Sports Exerc 5. Williford HN, Scharff-Olson M, 6. Long J, Williford HN, Scharff-Olson 25:S-81, 1993. Blessing DL: The physiological M, Wolfe V: Voice problems and risk 15. Vetter WL, Helfet DL, Speark K, effects of aerobic dance: A review. factors among aerobics instructors. J Matthews LS: Aerobic dance injuries Sports Med 8(6):335-345, 1989. Voice 12(2):197-207, 1998. symposium: Aerobic dance injuries.