Correlations between general joint hypermobility and joint hypermobility syndrome and injury in contemporary dance students.
JHS is a common and frequently overlooked syndrome that includes local or widespread musculoskeletal symptoms and joint laxity. (1,3) It is a "genetically inherited disorder, presenting with an autosomal dominant pattern, thought to affect the encoding of the connective tissue protein's collagen." (4) JHS is the most common of the heritable disorders of connective tissues (HDCT), but "unlike some of the better-known HDCTs, it does not reduce life expectancy, but it carries with it the greatest burden of pain and disability." (1) Pain is believed to be caused by the sensory nerve endings, which are over-stimulated by stretching and poorly supported by collagen fibrils. (1) Keer and Grahame go on to observe that it is not only movement per se that produces pain in the hypermobile patient but also sustaining a posture or repeating a particular movement for a prolonged period of time.
Hypermobile and over-stretched tendons and joints show lower levels of tendon reflex forces and muscle spindle and mechanoreceptor output, resulting in decreased proprioceptive acuity. (5) People with hypermobility are less accurate in tests of balance and judgment of joint angles. They appear to have an especially difficult time detecting the end-range of movement. (1,4) There are physiological characteristics that are visibly noticeable in hypermobile individuals, aside from the increased ROM in the joints. They tend to have flat feet in which, while non-weightbearing, there is a normal appearance with a full longitudinal arch, that flattens out immediately when it bears the body's weight. (1) Hypermobile people frequently have low muscle tone, even if they have been training and are physically fit. (4)
Hypermobility has been previously associated with dance, due to the high percentage of dancers who are hypermobile and the aesthetic appeal it has within the art form. (5,6) Desfor (5) suggests that although hypermobility may be an aesthetic asset for dancers, it may put them at risk for injury. Grahame (7) concurs by saying that hypermobility is a liability for the performing artist. hypermobility in dancers presents an inherent vulnerability to injury. According to Desfor's research, joints affected by hypermobility do not appear to have the neuromuscular safeguards of normal joints. Firm ligaments are not present to impose stability and limit excessive ROM, and people with hypermobility may be relatively unaware of when their joints and muscles are in hazardous positions. Reduced neuromuscular feedback may lead to biomechanically unhealthy limb positions, with the joint stretched further than the person perceives. (5,6) One of the mechanisms involved in the pathogenesis of JHS symptoms is likely to be a lack of control of the hypermobile joint range, the issue then being joint stability. (1)
The Beighton scoring system is commonly used as a reliable indicator of GJH. (4,7,8) This 9-point test requires the observer to establish, either actively or passively, that the subject is able to perform the movements listed in Table 1. (8) A score of 4 or more implies general joint laxity throughout the body. Gannon and Bird's comparative study of gymnasts and dancers found that the dancers had the higher mean Beighton score, 4.36/9, followed by gymnasts at 3.7/9. (9) These investigators suggest that the trunk hypermobility measurement is greatly affected by the dancers' training, and consequently does not represent their natural hypermobility. A Scandinavian study analyzing adolescent females compared figure skaters, gymnasts, and ballet dancers. (10) The dancers exhibited a statistically higher Beighton hypermobility score (average 5.1/9) when compared to the other sports (figure skaters 3.3/9, gymnasts 2.9/9). Purnell and colleagues' study of adolescent pre-professional ballet and theater students found a mean Beighton score of 4.62/9. (11) Klemp and Learmonth's study of a ballet company found that the dancers' Beighton score results were significantly higher than those of controls, but when the forward flexion score was removed from both groups, there was no longer a statistical significance. (12) This is another indication that the forward flexion test in the Beighton score is not accurate for dancers, due to their training.
The JHS phenotype has been characterized and classified according to validated criteria, termed the 1998 Brighton Criteria. (13) This measure of JHS goes beyond the Beighton score's measurement of ROM by taking into account symptoms and connective tissue deficiency. (7,13) There are two major and eight minor criteria, as shown in Table 2. JHS is diagnosed in the presence of two major criteria, one major and two minor criteria, or four minor criteria. Two minor criteria suffice when there is an unequivocally affected first-degree relative. Criteria Major 1 and Minor 1 are mutually exclusive, as are Major 2 and Minor 2. JHS is excluded by the presence of Marfan or Ehlers-Danlos syndromes, other than the Ehler-Danlos syndrome hypermobility type (formerly EDS III).
McCormack and colleagues' study of Royal Ballet School students used the Beighton score and the Brighton criteria to identify GJH and JHS respectively. (6) The Beighton scores were essentially the same in the Upper School and Company, suggesting that positive selection on grounds of hypermobility occurs early in a ballet career. The prevalence of JHS appeared to decrease as the dancers progressed from student to professional status. This decrease was also noticeable as the rank of company members increased, suggesting that JHS may impede a young dancer's chance of becoming a soloist or principal. McCormack and colleagues propose that the dancers with JHS most likely become too injured to continue dancing at the professional level. Koutedakis and Sharp (2) agree, suggesting that a hypermobile foot is a disadvantage for pointe work, and may prevent the dancer from gaining status in training or in a company.
A total of 85 contemporary dance students (female, N = 78; male, N = 7) participated in this study. Table 3 displays participant characteristics by gender and training level. All participants were from a full-time, 3-year Bachelor of Arts Dance Theatre degree program in the United Kingdom. Ethical approval from the program's Ethics Committee was obtained prior to testing. All participants completed a consent form and Medical Par-Q.
The screening procedure for each participant began by measuring height in meters (m) and weight (with footwear removed) in kilograms (kg). The Beighton score (Table 1) was then calculated. The forward flexion test was modified, due to results of previous research (see above). (3,5,9,12) Figure 1 illustrates what normally qualifies for a point in the Beighton score (A), and what this study used to qualify as a point (B). This modification has been previously suggested by researchers but has not yet been validated. The intention of this modification was to differentiate between forward flexion acquired from dance training and natural hypermobility. The participants were then verbally asked a series of past and current medical history questions related to the Brighton criteria (Table 2). They were allowed to ask for clarification if they did not understand any question, and examples were given if needed. The Steinberg test for arachnodactyly, in which the thumb is adducted across the palm, was considered a possible indication of marfanoid habitus, if the thumb projected beyond the ulnar boarder of the hand. (1) Skin stretch was measured by stretching the skin on the dorsum of the right hand to its maximum over the 3rd metacarpal bone. (1) An excessive amount of skin stretch was recorded.
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Participants completed a self-reported injury questionnaire that included type of injury (Table 4), injury frequency, and location. This questionnaire was created by the researcher based on Bronner and colleagues' study, (14) and included reference to Laws' Fit to Dance 2 questionnaires. (15)
The total number of participants with a positive Beighton score for GJH ([greater than or equal to] 4) was calculated, as was the total number of participants who met the Brighton criteria for JHS. The mean Beighton scores and standard deviation (SD) were calculated using the Statistical Package for Social Science (SPSS) Version 16.0 (SPSS Inc, Chicago, IL). The number and type of injuries sustained by each dancer was also totalled. The data from the physical testing, verbal questioning, and the questionnaire were then entered into SPSS for data analysis. Significance was set at p < 0.05. Pearson Correlation tests were used to analyze the variables.
Overall, 69% of the participants had GJH, and 33% had JHS. These results are further divided into program year and gender in Table 5.
Total number of injuries and time-loss injuries were significantly correlated with the Brighton criteria at the p < 0.01 level. One additional correlation was found between Physical Complaint Injuries and the Brighton criteria at the p < 0.05 level. No significant statistical correlation was found between GJH and injury. Table 6 shows statistical correlations and significance.
The study recorded the participants' Beighton scores with and without the forward flexion modification (Fig. 1). A total of 18 participants were affected by the modification. Of those 18, the modification would have changed the positive or negative result of the Beighton score in only one case. Overall, 71.76% of the participants sustained one or more injuries over a training period of 1 year. Table 7 shows the number and percentage of participants that sustained each quantity of injuries.
The 85 participants produced a total of 124 injuries. Sixty-eight of the injuries were classified as physical complaints, 40 were medical in nature, and 17 were time-loss injuries. Participants with a positive JHS score accounted for 58 injuries, 31 of which were physical complaints, 15 were medical, and 12 were time-loss. Seventy-one percent of all time-loss injuries involved participants with JHS. Participants with GJH had a total of 79 injuries: 46 were physical complaints, 23 were medical, and 10 were time-loss (Fig. 2). It is important to note that participants' injuries were counted in both the JHS and GJH categories if they had a positive result under both categories. Injuries for participants with negative Beighton and Brighton scores were also calculated. Those with no hypermobility had a total of 30 injuries: 18 physical complaints, 8 medical, and only 4 time-loss.
The percentage of participants with GJH in this study (69%) is slightly lower than that in McCormack and colleagues' ballet study, (6) but 22% higher than the previous contemporary dance study. (16) The mean Beighton score in this study (4.62/9 [+ or -] 2.28) is similar to previous research on dancers; it is identical to that found by Purnell and colleagues, (11) slightly higher than Gannon and Bird's study (4.36/9), (9) and slightly lower than Kujala and colleagues (5.1/9). (10) With regard to JHS, 33% of the contemporary dance students were positive for this syndrome, which is within the range (26%-47%) of McCormack and colleagues' ballet study. (6)
The statistical results indicate that time-loss injuries share a significant correlation (r = +.352, p = 0.001) with JHS. As noted above, 71% of all time-loss injuries in this study were found in participants with JHS. This might provide an explanation for the finding in McCormack and colleagues' study that showed a decrease in the number of professional ballet company members with JHS compared to that company's ballet school students. (6) Perhaps the dancers with JHS in the ballet school sustained time-loss injuries that hindered their training and prevented them from joining the company. If dancers with JHS are identified early in their training, injury prevention strategies can be put in place. Hence, it would be advisable for dance school and company screening programs to include both the Beighton test and Brighton Criteria to acquire GJH and JHS information on dancers. This information can be used in triage and physiotherapy sessions for enhanced management, and may also contribute to future research in the area. (4)
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Once JHS is recognized it is possible to formulate treatment plans, taking into account presenting signs and symptoms, previous history, and potential instability. Such plans should include prognosis and advice to allow persons at risk to manage their problem effectively themselves. (1,4) Keer and Grahame (1) suggest that the main aims of management programs are to increase function and reduce disability. Dancers with JHS should generally work to improve stability through increased muscular and neurological control. (1,4)
Overall, 71.76% of the participants sustained one or more injuries. This duplicates Purnell and colleagues' finding (71%) in 51 adolescent ballet and theater pre-professional students. (11) In the 2002 Dance UK survey, 81% of contemporary dancers (students and professionals) had incurred at least one injury in the last 12 months. (15) Another study (17) that assessed the prevalence of dance-related injuries in 141 professional ballet or modern dancers in the United Kingdom found (by way of a circulated questionnaire) that 84% had experienced an injury that affected their dancing at some time.
Above all, it is interesting to note that in the current study participants with GJH accounted for 64% of the injuries and those with JHS for 47%, while dancers with no hypermobility accounted for only 24% of injuries. This may well indicate that although GJH showed no statistical correlation with injury, it still represents an injury risk for dancers.
Desfor (5) suggests that hypermobility is an aesthetic component of dance, and increasing ROM in certain joints is a component of training. Future research would benefit greatly by a longitudinal study that measured ROM in each of its participants' joints upon entrance into a training program and continued such monitoring throughout the training process, thus increasing our knowledge of how training affects ROM and hypermobility in joints.
This study included a modification to the Beighton score that has not been validated. Future research might explore validating modifications of Beighton testing that would make it more specific to dancers, or perhaps there is even room for an altogether new, more dance-specific hypermobility test.
Research in this area might also consider exactly which joints are hypermobile, the extent of viable hypermobility in those joints, and what part they play in various dance genres. Comparisons could then be made between frequency and type of injury by genre, and whether GJH or JHS was present.
ROM in a dancer can vary considerably before and after a warm up. (18) Screening in this study took place from 9:00 a.m. to 5:00 p.m. over a week's time. Some dancers came from class already warmed up, while others did not. Warm-up procedures were not monitored or standardized in the methods of the study, as previous research suggests that natural hypermobility will be present with or without a warm up. (1) Test measurements were taken only once, which increased the risk of human error. Nonetheless, the same researcher carried out all of the testing, as that practice has shown previous reliability. (5)
The injury questionnaire was completed at the same time as questionnaires for other screening studies, and it appeared that many participants rushed through the questions. In some cases injury information was missing, which led to voids in the comparison of categories. Future research should monitor the questionnaire process more efficiently.
The Beighton score has been criticized because it gives no indication of the degree of hypermobility a person possesses. (4) In this study, GJH was simply considered to be present or not present, and the actual degree of hypermobility was not tested or included in the research.
The Brighton Criteria includes previous injuries such as dislocations and soft tissue rheumatic lesions in its diagnostic criteria. As one of the main predictors of future injury is previous injury, (14) it could be suggested that the correlation between JHS and injury was compromised by the lack of distinction introduced by the Brighton Criteria between previous and current injuries.
Overall, the high percentage of participants in this study with GJH (70%) and JHS (33%) indicates that hypermobility is a common attribute of contemporary dance students; hence, further research in this area could potentially benefit many dancers. In particular, the significant correlation found here between JHS and injury requires further investigation; specifically, it is suggested that dance screening programs should include use of the Brighton Criteria. Injury prevention programs of this sort, along with increased awareness among dance teachers and physiotherapists of the symptoms and characteristics of the syndrome, could play a role in the early detection of JHS. It is further suggested that research should include a longitudinal study of dance conservatory training to analyze the affect that training has on hypermobility. Future research might also include the development and validation of a dance-specific hypermobility testing method that could be used to correlate extent of hypermobility with risk of injury.
Caption: Figure 1 Normal qualification of forward flexion hypermobility (A) and this study's modified qualification (B).
Caption: Figure 2 Frequency and type of injury by hypermobility classification.
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(3.) Klemp P. Hypermobility. Ann Rheum Dis. 1997 Oct; 56(10):573-5.
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(10.) Kujala UM, Taimela S, Salminen JJ, Oskanen A. Baseline anthropometry, flexibility and strength characteristics and future low-back pain in adolescent athletes and non-athletes. Scand J Med Sci Sports. 1994;4:200-5.
(11.) Purnell M, Shirley D, Adams R, Nicholson L. Screening results associated with injury in female adolescent dance students. In: Solomon R, Solomon J. Proceedings of the 17th Annual Meeting of the International Association of Dance Medicine and Science, 2007. Canberra Australia: IADMS, 2007, pp. 236-40.
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(13.) Grahame R, Bird H, Child A. The revised (Brighton 1998) criteria for the diagnosis of benign joint hypermobility syndrome. J Rheumatol. 2000 Jul; 27:1777-9.
(14.) Bronner S, Ojofeitimi S, Mayers L. Comprehensive surveillance of dance injuries: a proposal for uniform reporting guidelines for professional companies. J Dance Med Sci. 2006;10:69-80.
(15.) Laws H. Fit to Dance 2: Report of the Second National Inquiry into Dancers' Health and Injury in the UK. London: Dance UK, 2005.
(16.) Garlington MD, Ojofeitimi S, Bronner S. Prevalence of joint hypermobility and correlation with injury in professional and student modern dancers: a preliminary investigation. Paper presented at: American Physical Therapy Association: Combined Sections Meeting, 2006, San Deigo, CA.
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Alia Ruemper, M.Sc., and Katherine Watkins, B.Sc., M.C.S.P., are from the Trinity Laban Conservatoire of Music and Dance, London, United Kingdom.
Correspondence: Alia Ruemper, M.Sc., Box 3772, Smithers, British Columbia, V0J 2N0, Canada; firstname.lastname@example.org.
Table 1 The 9-point Beighton Hypermobility Score (8) 1. Passively dorsiflex the fifth metacarpophalangeal joint to [greater than or equal to] 90[degrees] (Right/Left) 2. Oppose the thumb to the volar aspect of the ipsilateral forearm (Right/Left) 3. Hyperextend the elbow to [greater than or equal to] 10[degrees] (Right/Left) 4. Hyperextend the knees to [greater than or equal to] 10[degrees] (Right/Left) 5. Place the hands flat on the floor without bending the knees Maximum total 9 Scores [greater than or equal to] 4 are considered to indicate general joint hypermobility Table 2 The 1998 Brighton Criteria (13) Major Criteria 1. A Beighton score of 4/9 or greater (currently or historically) 2. Arthralgia for > 3 months in [greater than or equal to] 4 joints Minor Criteria 1. A Beighton score 1, 2, or 3/9 (0 if aged > 50 years) 2. More than 3 months arthralgia in 1-3 joints or back pain, spondylosis 3. Dislocation or subluxation in more than one joint, or in one joint on more than one occasion 4. Three or more soft tissue rheumatic lesions 5. Marfanoid habitus 6. Abnormal skin: striae, hyperextensibility, thin skin, papyraceous scarring 7. Eye signs: drooping eyelids, myopia, or antimongoloid slant 8. Varicose veins, hernia, or uterine or rectal prolapse Table 3 Characteristics of Participants by Gender and Training Level Mean and Standard Deviation BA1 BA1 Males (3) Females (44) Age (years) 19.33 [+ or -] 0.57 20.14 [+ or -] 1.96 Height (Meters) 1.82 [+ or -] 0.05 1.63 [+ or -] 0.06 Weight (Kilograms) 67.67 [+ or -] 6.81 53.16 [+ or -] 9.50 Body Mass Index 20.41 [+ or -] 1.57 20.52 [+ or -] 1.70 (Kg/[m.sup.2]) Mean and Standard Deviation BA3 BA3 Males (4) Females (34) Age (years) 23.00 [+ or -] 2.16 22.59 [+ or -] 2.15 Height (Meters) 1.80 [+ or -] 0.09 1.63 [+ or -] 0.07 Weight (Kilograms) 69.25 [+ or -] 6.33 55.31 [+ or -] 6.44 Body Mass Index 20.80 [+ or -] 1.56 20.81 [+ or -] 2.00 (Kg/[m.sup.2]) Table 4 Categories of Injury and Their Definitions (14) Category of Injury Definition Given to Participants Physical Complaint Injury 1. Ability to perform full dance activities, but feeling restricted by injury 2. Attended a triage session, but not a physiotherapy session Medical Injury An injury resulting in medical attention (physio., etc.) beyond triage Time-Loss Injury An injury resulting in inability to participate in activities (class, etc.) Table 5 Beighton and Brighton Results Number and % Number and % with with Positive Positive Beighton Score Brighton ([greater than or Criteria (JHS) equal to] 4) for GJH BA1 Males (N = 3) 1/3 (33%) 1/3 (33%) BA1 Females (N = 44) 12/44 (27%) 31/44 (70%) BA1 Overall (N = 47) 13/47 (28%) 32/47 (68%) BA3 Males (N = 4) 3/4 (75%) 2/4 (50%) BA3 Females (N = 34) 12/34 (35%) 25/34 (74%) BA3 Overall (N = 38) 15/38 (39%) 27/38 (71%) All Males (N = 7) 4/7 (57%) 3/7 (43%) All Females (N = 78) 24/78 (31%) 56/78 (72%) All Participants (N = 85) 28/85 (33%) 59/85 (69%) Mean Beighton Score and Standard Deviation BA1 Males (N = 3) 2.33 SD [+ or -] 2.52 BA1 Females (N = 44) 4.86 SD [+ or -] 2.18 BA1 Overall (N = 47) 4.70 SD [+ or -] 2.26 BA3 Males (N = 4) 3.75 SD [+ or -] 1.71 BA3 Females (N = 34) 4.66 SD [+ or -] 2.41 BA3 Overall (N = 38) 4.53 SD [+ or -] 2.32 All Males (N = 7) 3.14 SD [+ or -] 2.03 All Females (N = 78) 4.78 SD [+ or -] 2.26 All Participants (N = 85) 4.62 SD [+ or -] 2.28 Table 6 Statistical Correlations of Beighton and Brighton Results with Injuries Beighton Brighton Score Criteria (GJH) (JHS) Total Number of Injuries Pearson Correlation -.025 .331 ** Sig. (2-tailed) .818 .002 Physical Complaint Injuries Pearson Correlation -.026 .249 * Sig. (2-tailed) .810 .022 Medical Injuries Pearson Correlation .007 .060 Sig. (2-tailed) .948 .585 Time-loss Injuries Pearson Correlation -.030 .352 ** Sig. (2-tailed) .787 .001 ** Indicates significance to the p < 0.01 level; * indicates significance to the p < 0.05 level). Table 7 Percentage of Participants by Number of Injuries Number of Number of Percentage of Injuries Participants Participants 0 injury 24/85 28.23% 1 injury 23/85 27.06% 2 injuries 22/85 25.88% 3 injuries 10/85 11.76% 4 injuries 3/85 3.53% 5 injuries 3/85 3.53%
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|Author:||Ruemper, Alia; Watkins, Katherine|
|Publication:||Journal of Dance Medicine & Science|
|Date:||Oct 1, 2012|
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