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Background Joint hypermobility is considered to be both an advantage and a disadvantage. However, the degree of hypermobility in members of particular occupations requiring intense physical activity and the nature of the association between symptoms referable to specific joints and their hypermobility are unknown.
Methods We interviewed 660 musicians (300 women and 360 men) about work-related symptoms such as joint pain and swelling and examined them for joint hypermobility according to a standard protocol. We then determined the relation between the mobility of their fingers, thumbs, elbows, knees, and spine and any symptoms referable to these regions.
Results Five of the 96 musicians (5 percent) with hypermobility of the wrists, mostly instrumentalists who played the flute, violin, or piano, had pain and stiffness in this region, whereas 100 of the 564 musicians (18 percent) without such hypermobility had symptoms (P = 0.001). Hypermobility of the elbow was associated with symptoms in only 1 of 208 musicians (<1 percent), whereas 7 of 452 (2 percent) without this hypermobility had symptoms (P = 0.45). Among the 132 musicians who had hypermobile knees, 6 (5 percent) had symptoms, whereas only 1 of 528 (<1 percent) with normal knees had symptoms (P<0.001). Of the 462 musicians who had normal mobility of the spine, 50 (11 percent) had symptoms involving the back, as compared with 46 of the 198 musicians (23 percent) who had hypermobility of the spine (P<0.001).
Conclusions Among musicians who play instruments requiring repetitive motion, hypermobility of joints such as the wrists and elbows may be an asset, whereas hypermobility of less frequently moved joints such as the knees and spine may be a liability.
The frequency of joint hypermobility varies, but it is generally agreed that its occurrence depends on factors such as ethnic background, sex, and age5,6,7. For example, in a study of male Iraqi students, 25 percent were considered to have joint hypermobility, defined as excessive mobility of at least three of five joints. On the other hand, in a study of 1181 black South Africans of all ages and both sexes, 5 percent had hypermobility, defined as involvement of at least four of nine joints6. Sutro8 estimated that 4 percent of U.S. naval officers had joint hypermobility, defined as an "abnormal increase in the range of active and passive motion." In general, hypermobility is more frequent among women than men9 and more frequent among children than adults8.
Joint hypermobility has been considered beneficial to ballet dancers and harmful to young athletes10,11. We undertook a study of musicians to determine the possible relation between joint symptoms and hypermobility of their joints. Broadly speaking, the vocational activities of musicians are of two types. The first type consists primarily of fine repetitive motions involving little force -- for example, playing the flute or violin; the second involves use of large muscles and substantial force -- for example, playing percussion instruments.
Methods
Subjects
We studied 660 students and staff members at the Eastman School of Music (Rochester, N.Y.). There were 300 women and 360 men, ranging in age from 14 to 68 years (mean [±SD], 25 ±9]). These subjects accounted for 85 percent of the students and 69 percent of the staff members of the school; the remainder either declined to participate or could not be reached. The subjects played virtually all orchestral instruments (575 subjects) or were students of voice (85 subjects). We chose to conduct the study in the main hall of the school over a three-week period, because the students had to pass through the hall several times a day on their way to and from music lessons. The study protocol was approved by the Research Subjects Review Board at the University of Rochester, and all study subjects gave informed consent.
A 53-item questionnaire was used to interview the subjects about the musical instruments they played, the duration and intensity of their musical activity, and the nature of any musculoskeletal symptoms that they had while attending music school. The questions regarding musculoskeletal symptoms asked about their frequency (e.g., daily or weekly) and the location and severity of symptoms such as pain, cramps, weakness, stiffness, and redness (e.g., whether they interfered with routine musical activity or required medication). We examined the joints of each subject, using a modification of the Carter-Wilkinson protocol6,12. The specific criteria for hypermobility were (1) passive hyperextension of the wrists so that the fingers, when dorsiflexed, were parallel to the dorsum of the forearm, (2) passive opposition of the thumbs so that they touched the flexor aspect of the forearm (Figure 1A), (3) hyperextension of the elbows by 10 degrees or more beyond a straight line (Figure 1B), (4) hyperextension of the knees by 10 degrees or more beyond a straight line, and (5) flexion of the trunk in a standing position with the knees straight so that the palms rested on the floor. If the criteria for hypermobility of a joint or joints were not met, the subject was considered not to have hypermobility. In the evaluation of the upper extremities, only the dominant or playing side was examined. Our hypothesis was that hypermobility was beneficial; therefore, any conclusion that it was beneficial was based on the absence of symptoms.
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The data from the questionnaires and the examinations of joints were collated, and summary statistics were calculated with the SAS computer program (SAS Institute, Cary, N.C.). We compared the various symptoms of joint hypermobility and related findings using Fisher's exact test (two-tailed)13 and Zelen's test for the homogeneity of odds ratios14. The analysis included only symptoms that interfered with musical activity and occurred daily, and not intermittent or mild symptoms. The analysis also considered the possible beneficial or detrimental relation between hypermobility and the playing of families of instruments.
Results
The musicians usually practiced four to five hours daily. At this level of activity, 77 percent had daily symptoms such as pain, weakness, and fatigue in their extremities. The daily problems caused by hypermobility were not related to the total number of hypermobile joints in a subject but rather to the use of certain joints when playing particular instruments. In general, musicians with hypermobility of specific joints reported definite symptoms more often than those who did not have hypermobility of the same joints. Because of the small number of subjects, men and women were not evaluated separately except in analyses of the spine.
Only 5 percent of the subjects who had hypermobile wrists and fingers reported any musculoskeletal symptoms, as compared with 18 percent who did not have hypermobility of the fingers (P = 0.001) (Table 1). The percentage reporting musculoskeletal symptoms among the subjects with hypermobility of the thumb (6 percent) was not significantly different from that (9 percent) among the subjects without such hypermobility (P = 0.28).
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The percentage of subjects (5 percent) reporting symptoms among those with hypermobile knees (joints not involved in repetitive motion) was significantly higher (P<0.001) than the corresponding percentage (<1 percent) among the subjects without such hypermobility (Table 1).
The proportion of subjects with hypermobility of the spine who had symptoms involving the back (23 percent) was significantly higher than the proportion (11 percent) of subjects who did not have such hypermobility (P<0.001). The frequency of hypermobility of the spine among women was remarkably higher than that among men (50 percent vs. 13 percent) (Table 2). Among the women, the frequency of symptoms was significantly higher (P<0.001) among those who had hypermobility than among those who did not.
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Most previous studies15,16,17,18 of the medical problems of musicians have focused on the location of various symptoms according to the instruments played, but have ignored the possible role of joint hypermobility. Our results suggest that the musculoskeletal symptoms associated with practice and performance may be due to a lack of hypermobility of some joints involved in intensive repetitive motion, or due to hypermobility of joints not involved in repetitive motion but associated with support function. Specifically, subjects who played instruments requiring much repetitive motion had symptoms that affected their joints less often if the joints involved in the repetitive motion were hypermobile than if they were not hypermobile. In this situation, hypermobility can be considered an asset. Conversely, subjects with hypermobile joints not involved in repetitive motion but subjected to stress during the activity more often had symptoms than those with joints that were not hypermobile. Hypermobility of these joints can be considered a liability. Thus, hypermobility of the thumb and wrist (including the fingers) can be an asset in playing instruments such as the flute, violin, and piano. On the other hand, hypermobility of the spine and to some extent hypermobility of the knees can be a liability during long periods of practice and performance. The stresses on the latter joints may be explained in terms of the overuse syndrome -- i.e., pain in muscles involved in support function19. Physicians considering the problems of musicians and possibly similar problems of other workers may find it desirable to distinguish between persons with hypermobility of joints serving different functions. With respect to the occupational symptoms of musicians, such distinctions may be relevant in counseling related to changes in posture, the method of playing, the duration of practice, or even the choice of instrument.
Our study suggests that the clinical evaluation of the effects of repetitive motion is best approached by grouping joints according to their involvement in repetitive motion, as follows: joints related to the activity, joints marginally related to the activity (involved but not to a major degree), and joints unrelated to the activity.
During the past century and especially the past decade, concern about and interest in the musculoskeletal problems of musicians have increased greatly15,16,17,18. The studies of these problems have resulted in the introduction of terms such as "repetition strain,"20 "overuse syndrome,"20 and "musician's cramp"20 to describe symptoms such as pain, stiffness, cramping, and tingling. No one has yet demonstrated muscle or joint injury in musicians who have musculoskeletal symptoms19. These terms deserve to be defined with care and used with caution in attempts to describe physiologic changes and motion disorders in joints.
Hypermobility may be inherited21. Those not so endowed may acquire some degree of hypermobility in the process of training, during which symptoms such as pain and stiffness may occur. Our results support the existence of relations between hypermobility or non-hypermobility of various joints and a successful or at least asymptomatic career in music.
Since the frequency of hypermobility in the general population is not known, we do not know whether musicians have more or less hypermobility than average. It may not be appropriate to compare our results with those obtained in studies of other groups,9 such as schoolchildren,22 and racial groups, such as Asians5 and Africans6. Hypermobility seems to decline with age23. A comparison of the high frequency of hypermobility in our subjects with the frequency reported in the population at large suggests that hypermobility may influence some persons to become musicians, just as others may become dancers10.
We conclude that in musicians, hypermobility of specific joints undergoing repetitive motion is an asset but hypermobility of joints giving support is a liability. The question of whether hypermobility is an asset or a liability, although addressed in dancers,10 young athletes,11 and now musicians, has not been raised with respect to those in the workplace. More generally, studies of the relation between musculoskeletal symptoms and joint hypermobility may be helpful in linking work and joint problems related to it.
We are indebted to Mr. Deo Kumar Srivastava for assistance in analyzing the study results, to Dr. Paul Burgett for support and encouragement, and to Ms. Diane McMullan for assistance in the preparation of the manuscript.
Source Information
From the Arthritis and Clinical Immunology Unit, Monroe Community Hospital, University of Rochester School of Medicine and Dentistry, Rochester, N.Y. (L.-G.L., J.B.); the Hospital for Rheumatic Diseases, Ostersund, Sweden (L.-G.L.); and the University of Rochester Department of Statistics, Division of Biostatistics, Rochester, N.Y. (G.S.M., G.D.K.).
Address reprint requests to Dr. Baum at Monroe Community Hospital, 435 E. Henrietta Rd., Rochester, NY 14620.
References
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