|Year : 2021 | Volume
| Issue : 3 | Page : 93-101
Generalized joint hypermobility, musculoskeletal injuries, and psychological factors among dancers in Lagos state
Ashiyat Kehinde Akodu1, Yusuf O Balogun1, Oladunni Caroline Osundiya1, Caleb A Adeagbo1, Ibironke Esther Ogunleye2
1 Department of Physiotherapy, College of Medicine, University of Lagos, Lagos, Nigeria
2 Department of Physiotherapy, University of Medical Sciences Teaching Hospital, Ondo State, Nigeria
|Date of Submission||04-Oct-2021|
|Date of Acceptance||20-Oct-2021|
|Date of Web Publication||13-Dec-2021|
Ashiyat Kehinde Akodu
Department of Physiotherapy, Faculty of Clinical Sciences, College of Medicine, University of Lagos, Lagos
Source of Support: None, Conflict of Interest: None
Introduction: Dancers are athletes who are vulnerable to musculoskeletal injuries and hypermobility, and their emotional level is very important for optimal performance.
Objective: To evaluate the prevalence of generalized joint hypermobility (GJH) and its association with musculoskeletal injuries and psychological factors among dancers in Lagos state.
Materials and Methods: This was a cross-sectional analytical survey involving 114 dancers (54 males and 60 females), selected from two dance groups in Lagos state. The participants completed a 31-item musculoskeletal pain questionnaire, 9-item validated Beighton index, and 21-item depression, anxiety, and stress scale. Data were analyzed using inferential statistics of Chi-square and summarized using mean, standard deviation, frequency, and percentages at alpha level of 5%.
Results: The results showed that the 12-month prevalence of musculoskeletal disorders among dancers was 77 (67%), and the knee, 25 (21.9%), was the most commonly affected body site. The prevalence of GJH was 81 (71.1%), with the majority having distinct hypermobility. The level of anxiety among dancers was extremely severe, 35 (30.7%). There was no significant association (P = 0.487) between GJH and the 12-month prevalence of musculoskeletal injuries and psychological factors (P > 0.05) among dancers.
Conclusions: There was a high prevalence of musculoskeletal injuries and joint hypermobility among dancers. The knee was the most frequently injured joint. The majority of the dancers' joints are distinctly hypermobile, and most of the dancers have extremely severe anxiety. Musculoskeletal injuries and psychological factors did not influence GJH.
Keywords: Anxiety, dancers, depression, joint hypermobility, musculoskeletal injury, stress
|How to cite this article:|
Akodu AK, Balogun YO, Osundiya OC, Adeagbo CA, Ogunleye IE. Generalized joint hypermobility, musculoskeletal injuries, and psychological factors among dancers in Lagos state. Saudi J Sports Med 2021;21:93-101
|How to cite this URL:|
Akodu AK, Balogun YO, Osundiya OC, Adeagbo CA, Ogunleye IE. Generalized joint hypermobility, musculoskeletal injuries, and psychological factors among dancers in Lagos state. Saudi J Sports Med [serial online] 2021 [cited 2023 Jun 8];21:93-101. Available from: https://www.sjosm.org/text.asp?2021/21/3/93/332394
| Introduction|| |
Dancers are unique blend of artist and athlete, particularly susceptible to musculoskeletal injuries and pain. Sport plays a significant role in education and socialization, patriotism and community spirit, recreation and health enhancement, and well-being and entertainment.
Joint hypermobility (JH) is a condition in which a joint stretches beyond the normal range of motion, and this is classified into single-joint or generalized subtypes. Joint hypermobility syndrome (JHS) occurs in an individual who presents with hypermobile joints in the absence of demonstrable rheumatologic disease.
The reported prevalence and incidence of JHS vary in the literature. The prevalence of JHS in adult population has been reported to range from 10% to 30%. While the prevalence of JH was reported to be 64.9% in a cohort jazz dancers, another study reported the prevalence to be as high as 44% among student dancers. Joint laxity is usually greatest at birth, decreases during childhood, and reduces during adolescence and adult life. A study by Anbarasi et al. reported reduced muscle flexibility, especially in the hamstrings among dancers which result into musculoskeletal disorders.
Some dancers are hypermobile and do not have a history of pain and injury, and they can utilize their level of flexibility and avoidance of injury to succeed in their choice of career. However, some hypermobile individuals will experience both pain and injury. Excellent joint proprioception and balance are required by all dancers to achieve proper control, while dancers who are hypermobile will require more effort to improve joint proprioception.
Musculoskeletal injury is a regularly reported health issue among classical and modern dancers. The majority (60%–80%) of dancers in a Nigerian study by Aweto et al. reported at least one injury that has affected their dancing or kept them from dancing. Biomechanical factors, environmental and training problems, and technical capability cause dance-related injuries. Injury occurs mostly in the late afternoon which is a reflection of muscular and psychological fatigue.
Dance psychology is a burgeoning area of research within the broader field of dance medicine and science. Studies have been done in the area of dance psychology, including performance anxiety and injury psychology, while studies addressing the role of psychological factors within talent or career development are very few.
Therefore, this study was designed to investigate the prevalence of generalized joint hypermobility (GJH) in association with musculoskeletal injuries and psychological status among dancers in Lagos state.
| Materials and Methods|| |
A descriptive cross-sectional analytical survey was carried out between January and August 2021. It involved 114 dancers with the sample size derived from the formula by Cochrane that is where Z = standard normal variate (at 5%), Type 1 error (P < 0.050) is 1.96, and P is the prevalence of musculoskeletal disorders among dancers with a value of 86.1%. The participants were volunteers from two dance groups in Lagos state selected using the purposive sampling technique.
The study included professional and nonprofessional dancers who are registered members of a dancing school in Lagos state and who do not have any injury at the time of the study. At the same time, professional dancers who have retired were not allowed to participate in the study.
Before commencing the study, consent to participate in the study was obtained from all participants. Approval to conduct the study was granted by the Health Research and Ethics Committee of College of Medicine University of Lagos with approval ID: CMUL/HREC/12/19/706. The aim and objectives of this study were clearly explained to the participants, and they were assured of the confidentiality of their data.
Measurement of height and weight was done and the body mass index was calculated with the formula; weight/height.
Measurement of hypermobility
After completing the questionnaire, the participants were assessed for hypermobility using the validated Beighton index hypermobility questionnaire via a goniometer. Nine items were scored based on the ordinary score of 0–9, with a higher score representing greater joint mobility. Each individual item was scored using a nominal scale in which “1” represents a positive sign and “0” represents a negative sign. For the first score, the subjects sat next to the table or plinth with the shoulder in 80° of abduction, elbow was flexed to 90°, and the forearm was pronated. Then, a passive extension was performed at the fifth metacarpal, and if a 90° extension is achieved with the aid of the goniometer, it is a positive test; this was repeated on the other limb. The second score was done while the subjects were seated on the chair facing the table. The shoulder was flexed to 90° with the forearm supinated, and the elbow extended, and then elbow hyperextension was passively checked. Ten or more degrees of elbow hyperextension with the aid of the goniometer indicates a positive test, and this was repeated on the other limb. For the third score, the subjects were in supine lying position, and then, knee hyperextension was checked for 10° or more degrees of hyperextension with the aid of the goniometer indicating a positive test, which was repeated on the other limb. For the fourth score, the subjects flexed the shoulder to 90°, extended the elbow, and pronated the forearm; then, the subjects tried to bend the thumb to the flexor side of the forearm, if the subjects were able to do so, this indicated a positive score, and this was repeated on the other limb. For the last score, the subjects were told to bend over and try to touch the floor with flat hands while keeping their legs fully extended; the ability of the subjects to do so indicates a positive test.
Two types of questionnaire, including the musculoskeletal pain and injury questionnaire and the Depression Anxiety, Stress Scales (DASS) questionnaire were used to assess the participants' musculoskeletal pain and psychological status. These self-administered questionnaires were distributed to the participants and were collected after completion by the researcher.
The musculoskeletal pain and injury questionnaire
It was adopted from the study by Aweto et al. on “Prevalence of musculoskeletal pain and injury amongst professional dancers.” It has 31 questions with 6 sections; Section A collected demographic data of participants which includes age, sex, height, weight, body mass index, and years of experience of dancing. Section B collected information on history of the participants. Section C collected information on prevalence of musculoskeletal injuries of the participants. Section D consists of questions on the predisposing factors to musculoskeletal pain and injury. Section E sought information on the participants' limitation due to pain and injury. Section F collected data on the participants' treatment history.
Depression, Anxiety, and Stress Scale questionnaire
DASS is a clinical assessment scale that measures the three related states of depression, anxiety, and stress. It has 21 questions and takes about 3 min to complete, each reflecting a negative emotional symptom. The DASS-21 is a short form version of the DASS (the long form has 42 items); the final score of each item group was multiplied by two. These scores range from 0, meaning that the client believed the item “did not apply to them at all,” to 3, meaning that the client considered the item to “apply to them very much, or most of the time,” with 14 questions for depression, anxiety, and stress, respectively. It is also stressed in the instructions that there are no right or wrong answers. The reliability scores of the scales in terms of Cronbach's alpha scores rate the depression scale at 0.91, the anxiety scale at 0.84, and the stress scale at 0.90 in the normative sample.
The data were analyzed using Statistical Package for the Social Sciences IBM SPSS version 25, New York city, New York, USA for Windows and summarized using descriptive statistics of mean, standard deviation, frequency, and percentage. Inferential statistics of Pearson's Chi-square test was used to find an association between variables at an alpha level of 5%.
| Results|| |
A total of 160 copies of the questionnaire were distributed, and 114 copies were returned. This gave a response rate of 71.2%. Therefore, 114 copies of the questionnaire were valid for analysis. The study population has a mean age of 21.35 ± 3.09 years. The majority, 81 (71.1%), of the participants have normal weight; only two (1.8%) are obese while 19 (16.7%) are overweight [Table 1]. The majority of the participants, 90 (78.9%), have the right leg as their dominant leg, while 17 (14.9%) use left as their dominant leg and 7 (6.1%) of the participants make use of both legs.
| Dancing history of the participants|| |
Eight-seven (76.3%) participants are professional dancers while 27 (23.7%) of the participants are nonprofessional dancers. Among the professional dancers, 62 (54.4%) have been dancing professionally for 1–3 years, 16 (14.0%) have been dancing professionally for 4–6 years, 3 (2.6%) have been dancing professionally for 7–9 years, and 6 (5.3%) have been dancing professionally for 10–12 years.
Furthermore, most of the participants partake in more than one type of dance, and from the result, 88 (77.2%) of the participants dance Hip-hop, 40 (35.1%) partake in Contemporary dance, 44 (38.6%) partake in African contemporary dance, 24 (21.1%) partake in Salsa, 63 (55.3%) partake in African dance, 14 (12.3%) partake in Jazz, 18 (15.8%) partake in Ballet, 9 (7.9%) partake in Tango dance, 13 (11.4%) partake in Ball room dance, 21 (18.4%) partake in Aerobic dance, 11 (9.6%) partake in Waltz, and 23 (20.3%) partake in other forms of dance.
Twenty-two (19.3%) of these dancers train daily, 18 (15.8%) train once in a week, 35 (30.7%) train twice in a week, and 23 (20.2%) train thrice in a week. In addition, 30 (26.3%) of the participants train for an average of 1 h in a day, 31 (27.2%) train for an average of 2 h in a day, 29 (25.4%) train on an average of 3 h in a day, 11 (9.6%) train on an average of 4 h in a day, and 13 (11.4%) train for more than 5 h in a day.
The majority of the participants, 61 (53.5%), reported that they were not feeling pain presently, while 53 (46.5%) were feeling pain presently. Among the 53 participants who were having pains as at the time of the study, 3 (5.7%) reported a pain score of 1, 6 (11.3%) reported a pain score of 2, 6 (11.3%) reported a pain score of 3, 10 (18.9%) reported a pain score of 4, 9 (17.0%) reported a pain score of 5, 7 (13.2%) reported a pain score of 6, 5 (9.4%) reported a pain score of 7, 3 (5.7%) reported a pain score of 8, 2 (3.8%) reported a pain score of 9, and 1 (1.9%) reported a pain score of 10.
Most of the injury that affected the participants resulted from strain 23 (43.4%), 10 (18.9%) had fracture, 6 (11.3%) had sprain, 5 (9.4%) had scrape (cut), 3 (5.7%) had bruises, 2 (3.8%) had tendonitis, 8 (15.1%) had swelling, 2 (3.8%) had dislocation, and 7 (13.2%) had other forms of injury.
Point and 12-month prevalence of musculoskeletal disorders of the participants and the body part affected
[Table 2] shows that 77 (67.5%) of the participants had felt pain in the past 1 year. Sixty-seven (58.8%) of the participants had injury and pain during dancing. Six (5.3%) of the participants get injured daily, and 14 (12.3%) of the participants get injured monthly. Knee, 25 (21.9%), was the body part mostly affected by musculoskeletal disorders followed by the lower back; 17 (14.9%), ankles and feet; 17 (14.9%), thighs (back); 14 (12.3%), neck; 11 (9.6%), wrist and hand; 10 (8.8%), toes; 10 (8.8%), hips; 7 (6.1%), elbow; 5 (4.4%), thighs (front); 5 (4.4%), mid-back; 3 (2.6%) and calves; while 2 (1.8%) occurred in the shin. However, some of the participants gave multiple responses.
|Table 2: Point and 12-month prevalence of musculoskeletal disorders of the participants (n=114)|
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Prevalence of joint hypermobility and psychological status of the participants
In [Table 3], the prevalence of JH was reported to be 97 (85.1%), but most of the participants, 81 (71.1%), were distinctly hypermobile. [Table 4] shows that 20 (17.5%) participants were moderately depressed and 7 (6.1%) were severely depressed. Twelve (10.50%) participants were moderately stressed, and 12 (10.50%) were severely stressed. Twenty-three (20.20%) participants had severe anxiety and 35 (30.70%) had extremely severe anxiety.
Association between age, sex, years of experience, frequency of training, prevalence of musculoskeletal disorders, psychological status, and generalized joint hypermobility
In [Table 5], there was no association between age (P = 0.086), sex (P = 0.544), frequency of training (P = 0.237), and GJH, while there was an association between years of experience (P = 0.026) and GJH. It was also observed that there was no association between 12-month prevalence of musculoskeletal injury and GJH (P = 0.487) [Table 6]. [Table 7] shows that there was no association between depression (P = 0.544), anxiety (P = 0.357), stress (P = 0.350), and GJH.
|Table 5: Association between age, sex, year of experience, frequency of training, and generalized joint hypermobility of the participants|
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|Table 6: Association between point, 12.month prevalence of musculoskeletal injury, and generalized joint hypermobility|
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|Table 7: Association between depression, anxiety, stress and generalized hypermobility of the participants|
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Association between age, sex, years of experience, frequency of training, psychological status (depression, anxiety, and stress), and 12-month prevalence of musculoskeletal pain
[Table 8] shows that there was no association between age (P = 0.088), sex (P = 0.849), years of experience (P = 0.078), and 12-month prevalence of musculoskeletal pain, but an association exists between frequency of training (P = 0.044) and 12-month prevalence of musculoskeletal pain. It was observed in [Table 9] that there was no association between depression (P = 0.277), anxiety (P = 0.232), stress (P = 0.082), and 12-month prevalence of musculoskeletal pain.
|Table 8: Association between age, sex, years of experience, frequency of training, and 12.month prevalence of musculoskeletal pain|
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|Table 9: Association between depression, anxiety, stress and 12-month prevalence of musculoskeletal pain|
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| Discussion|| |
This study was embarked on to explore the prevalence of GJH in association with musculoskeletal injuries and psychological status among dancers in Lagos.
The study outcome revealed that 67.5% of dancers reported musculoskeletal pain and injury in the last 12 months. This implies a high prevalence of musculoskeletal pain and injury among them. This level of prevalence may be as a result of anatomic alignment, poor training, technical errors, unfamiliar choreography or style, and extrinsic factors, including flooring surfaces and theatre temperature, which have been implicated as contributing factors to the high prevalence of dance injuries.
The knee (21.9%) was the most commonly injured body part among the dancers particularly for the different types of dance followed by the low back (14.9%) and ankle (14.9%) which concurs with the research carried out by Aweto et al. The finding that the frequently injured area was knee, especially for most of the dance types, followed by the low back and ankle corroborates previous report by Rickman et al., who observed that most musculoskeletal disorders occurred at the lower back and lower extremities. This may be as a result of the anatomic structures of these areas and the demands made on them when performing the different dance styles. The joints of the lower extremities bear much of the weight of the body. This may also be another contributing factor. Wainwright et al. stated that the occurrence of injuries is related to the type of dance being performed, the dancer's technique, experience, physiology, and psychological factors. Shah et al. observed that the most common injury sites were the foot and ankle, lower back, and knee among dancers in the United States of America.
Most of the dancers who were having pains at the time of this study had strain (43.4%) as the type of injury that affected them the most, followed by fracture (18.9%) and then swelling (15.1%). This may be the aftermath effect of the strong influence of dancing on the body coupled with the different maneuvers the musculoskeletal system is exposed to while dancing. This assertion was corroborated by the studies of Cho et al. and Aweto et al. The fracture could be attributed to the female athlete triad amenorrhea, disordered eating, and low bone density, which has been implicated in an increased risk of stress fractures in dancers by Negus et al. The average severity of pain was reported for most of the dancers who were injured. This may be due to the subjectivity of pain severity rating, and it is not a true indicator of how individuals perceive pain severity. This is in line with the report of the studies by Lai et al. and Aweto et al.
This study points out that the prevalence of JH was 85.1% while most dancers are distinctly hypermobile (71.1%) and female dancers are more distinctly hypermobile than their male counterparts. This may be due to the requirement of the task they have to perform to produce a desired performance. This finding was corroborated by a research carried out by Scheper et al. that most dancers are distinctly hypermobile. The result that female dancers are more hypermobile than their male counterparts was supported by Jansson et al., and they stated that the cause of this is idiopathic.
This study showed that the stress level and depression level in dancers are normal while the anxiety level in dancers are extremely severe, and this may be attributed to the expectations that they intend to achieve during their auditions, dance classes, and the learning of some particular dance moves before each performance. This high percentage in their anxiety level was supported by Scheper et al. Sahin et al.
This study showed no association between the age, sex, frequency of training of dancers, and GJH, while there was an association between the years of experience of dancers and GJH.
This study showed that there was no association between depression, anxiety, stress, and GJH. Although it was stated that there was a significant association between depression, anxiety, stress, and GJH by Bulbena et al. and Sahin et al., this may be because this study was carried out on adult dancers while previous studies were carried out on young children.
This study showed no association between the 12-month prevalence of musculoskeletal pain and injuries and GJH. This is not in line with what was revealed in the study by Sahin et al.
It was shown in this study that there was no association between age, sex, years of experience, and 12-month prevalence of musculoskeletal injuries, while there was a significant association between frequency of training and 12-month prevalence of musculoskeletal injuries among dancers in Lagos state. This means that the age of dancers has no influence on musculoskeletal pain and injury and this is in line with the study by Aweto et al. while Stretanski and Weber observed that there was a significant relationship between the age and prevalence of musculoskeletal pain and injury among professional dancers. This may be because all the dancers are subjected to the same rehearsal techniques and the pains experienced after each dance classes were not related to the age of the dancers. In this study, there was no association between the prevalence of musculoskeletal pain and injury among professional dancers and the training hours among professional dancers per day. This finding is in line with the report of Aweto et al.
This study revealed that there was no association between depression, anxiety, and stress and 12-month prevalence of musculoskeletal injuries among dancers in Lagos state. However, this is not in line with the study by Scheper et al. They were able to show that a significant relationship exist among psychological status, GJH, and musculoskeletal pain among dancers. This could be due to the number of participants that took part in this present study.
This study was limited due to the inadequate response of most of the dancing schools in Lagos state due to the ongoing COVID-19 pandemic and unwillingness to fully answer the questions in the questionnaire, due to the number of questions and their busy schedule.
| Conclusion|| |
There was a high prevalence of musculoskeletal pain and GJH among dancers in Lagos state, the knee followed by the lower back was the most commonly affected body part among the participants, most of the injuries of the dancers occurred during their training sessions, and the years of experience influenced the GJH in dancers. Frequency of training influenced 12-month prevalence of musculoskeletal injuries among dancers in Lagos state. Likewise, years of experience influenced musculoskeletal pain and injury felt by dancers during dancing. In addition, point and 12-month prevalence of musculoskeletal injuries were not influenced by the psychological status of the dancers and GJH.
The authors wish to appreciate the management of the dance schools and the dancers that were involved in this study.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
| References|| |
Aweto HA, Awolesi OM, Alao RO. Musculoskeletal pain and injury in professional dancers: Prevalence, predisposing factors and treatment. Indian J Phys Ther 2014;2:6-13.
Kumar V, Mangal A, Yadav G, Raut DK, Singh S. Prevalence and pattern of sport injuries among college student in Delhi, India. Saudi J Sports Med 2014;14:109-14. [Full text]
Smith R, Damodaran AK, Swaminathan S, Campbell R, Barnsley L. Hypermobility and sports injuries in junior netball players. Br J Sports Med 2005;39:628-31.
Grahame R. Hypermobility and the heritable disorders of connective tissue. In: Keer H, Grahame R, editors. Hypermobility Syndrome Recognition and Management for Physiotherapists. Ch. 2. London: Butterworth-Heinemann; 2003. p. 15-26.
Middletich A. Management of the hypermobile adolescent. In: Hypermobility Syndrome, Recognition and Management for Physiotherapists. Edinburgh: Butterworth Heinemann; 2003. p. 51-66.
Skwiot M, Śliwiński G, Milanese S, Śliwiński Z. Hypermobility of joints in dancers. PLoS One 2019;14:e0212188.
Day H, Koutedakis Y, Wyon MA. Hypermobility and dance: A review. Int J Sports Med 2011;32:485-9.
Clark CJ, Knight I. A humanisation approach for the management of Joint Hypermobility Syndrome/Ehlers-Danlos Syndrome-Hypermobility Type (JHS/EDS-HT). Int J Qual Stud Health Well-being 2017;12:1371993.
Anbarasi V, Rajan DV, Adalarasu K. Analysis of lower extremity muscle flexibility among Indian classical bharathnatyam dancers. Int J Med Health Biomed Bioeng Pharm Eng 2012;6:225-30.
Hakim AJ, Grahame R. A simple questionnaire to detect hypermobility: An adjunct to the assessment of patients with diffuse musculoskeletal pain. Int J Clin Pract 2003;57:163-6.
Malkogeorgos A, Mavrovouniotis F, Zaggelidis G, Ciucurel C. Common dance related musculoskeletal injuries. J Phys Educ Sport 2011;11:259-66.
Walker IJ, Nordin-Bates SM. Performance anxiety experiences of professional ballet dancers: The importance of control. J Dance Med Sci 2010;14:133-45.
Noh YE, Morris T, Andersen MB. Psychological intervention programs for reduction of injury in ballet dancers. Res Sports Med 2007;15:13-32.
Aujla IJ, Nordin-Bates SM, Redding E. A qualitative investigation of commitment to dance findings from the UK centres for advanced training. Res Dance Educ 2014;15:138-60.
Cochran WG. Sampling Technique. 3rd
ed. Canada: John Wiley and Sons; 1977.
Beighton P, Solomon L, Soskolne CL. Articular mobility in an African population. Ann Rheum Dis 1973;32:413-8.
Kwon JW, Lee WJ, Park SB, Kim MJ, Jang SH, Choi CK. Generalized joint hypermobility in healthy female Koreans: Prevalence and age-related differences. Ann Rehabil Med 2013;37:832-8.
Lovibond PF, Mitchell CJ, Minard E, Brady A, Menzies RG. Safety behaviours preserve threat beliefs: Protection from extinction of human fear conditioning by an avoidance response. Behav Res Ther 2009;47:716-20.
Lovibond PF, Lovibond SH. The structure of negative emotional states: Comparison of the Depression Anxiety Stress Scales (DASS) with the Beck Depression and Anxiety Inventories. Behav Res Ther 1995;33:335-43.
Rickman AM, Ambegaonkar JP, Cortes N. Core stability: Implications for dance injuries. Med Probl Perform Art 2012;27:159-64.
Wainwright SP, Williams C, Turner BS. Fractured identities: Injury and the balletic body. Health (London) 2005;9:49-66.
Shah S, Weiss DS, Burchette RJ. Injuries in professional modern dancers: Incidence, risk factors, and management. J Dance Med Sci 2012;16:17-25.
Cho CH, Song KS, Min BW, Lee SM, Chang HW, Eum DS. Musculoskeletal injuries in break-dancers. Injury 2009;40:1207-11.
Negus V, Hopper D, Briffa NK. Associations between turnout and lower extremity injuries in classical ballet dancers. J Orthop Sports Phys Ther 2005;35:307-18.
Lai RY, Krasnow D, Thomas M. Communication between medical practitioners and dancers. J Dance Med Sci 2008;12:47-53.
Scheper MC, de Vries JE, de Vos R, Verbunt J, Nollet F, Engelbert RH. Generalized joint hypermobility in professional dancers: A sign of talent or vulnerability? Rheumatology (Oxford) 2013;52:651-8.
Jansson A, Saartok T, Werner S, Renström P. General joint laxity in 1845 Swedish school children of different ages: Age- and gender-specific distributions. Acta Paediatr 2004;93:1202-6.
Sahin N, Atik A, Sargin S. Joint hypermobility syndrome and related pain. Arch Clin Exp Surg 2016;5:105-12.
Bulbena A, Agulló A, Pailhez G, Martín-Santos R, Porta M, Guitart J, et al.
Is joint hypermobility related to anxiety in a nonclinical population also? Psychosomatics 2004;45:432-7.
Stretanski MF, Weber GJ. Medical and rehabilitation issues in classical ballet. Am J Phys Med Rehabil 2002;81:383-91.
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6], [Table 7], [Table 8], [Table 9]