Muscular effort and musculo-skeletal disorders in piano students - epm

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71 698 A. Grieco et al.PIOn the basis of these bibliographic references of 100 years ago, Australian authorsrecognized the close similarities between pianist's cramp and the `overuse syndrome'defined as `those changes brought about in the muscles and joint ligaments fromexcessive use, causing pain, loss of function, and almost always demonstrabletenderness in the affected structures'. (Fry 1986, 1987).In a study made in seven of Australia's 11 music schools, covering 409 pianostudents, it was found that 9% of the students were affected by the overuse syndrome to amore or less marked degree. The syndrome was much more frequent in females (7%) thanin males (2%). The saure author reported that the overuse syndrome affects morethan 50% of the musicians in modern Symphony orchestrar in Australia.There has been a tendency to demand increasing technical performance frommodern concert pianos. The Grober concert piano of the early 19th century involvedabout 6 mm travel of the key and required a force of about 23 g to depress the key, with atension of the middle string section of 12 to 15 kg, whereas the modern Steinwayinvolver about 10 . 5 mm travel, a depression pressure of about 50 to 60 g and 90 kgtension (Fry 1986).On the basis of these observations, we undertook an investigation which had thefollowing aims:1. Estimate the frequency of disorders of the locomotor apparatus in pianostudents of the Milan Conservatory.2. Assess the effort of various muscle groups during piano practice by means ofvocational electromiography techniques, and also o utline a mode) fororganization of practice during the week.3. Identify prevention measures, with particular emphasis on ways to changestudents' individua) attitudes and train them in suitable mobilization, relaxationand stretching exercises.2. Methods2.1. Analysis of study day organization and analysis of musculo-skeletal disordersA specially developed questionnaire was used, divided finto three parts, i.e.:(a) generai information and features of organization of study and free time;(b) occurrence, site, and characteristics of any musculo-skeletal disorders;(c) occurrence of psychic, respiratory or digestive complaints.A total of 117 completed questionnaires were collected (54 males and 63 females),equivalent to a response rate of about 75% of the students contacted. The compositionof the respondents, by age class, is shown in table I.2.2. Electromyographic study2.2.1. subjects: The electromyographic study covered six piano students (three malesand three females) enrolled for the fina) years of the course. The subjects participated inthe experiment voluntarily. Generai anthropometric parameters (weight, height) weremeasured for all subjects, plus a number of specific parameters of the hand such asbreadth, length of the third finger, length of the hand at the third finger, angles betweenfingers at maximum aperture. The relative percentile was calculated for all parameters.2.2.2. Selected piano exercises: In order to standardize the exercises performed by thesix subjects, a set of standard exercises of varying difficulty was selected, each involving
Muscular effort and musculo-skeletal disorders in piano students 699Table I. Distribution of piano students examined via questionnaire, by age class and years ofstudy.Age classyearsNumberYears of studySC8-10 9 211-13 26 3.914-16 29 6.117-19 21 9.2620-22 20 11.223-25 8 10.8>25 4 16.5Total number of subject examined N=117.a different use of the hand/forearm system. The exercises were taken from Hanon (aclassic volume of preparatory exercises widely used in piano teaching) and wereclassified in groups according to the different aspects of muscular effort (figure 1). Eachexercise was performed at two speeds: (a) the minimum speed for the score; (b) thestudent's maximum possible speed. Also, each subject performed an unseen passage(Scott Joplin's 'Elite Syncopation') which was played again after 15 min practice.Each student then performed one or two passages from his/her repertoire whichhe/she considered to be the most difficult. Here, it was obviously not possible tostandardize the exercises so no comparison could be made, except for the Tirstvariation on a theme of Paganini-Brahms', which all three male students performed.2.2.3. Vocational electromyography: The processing method used was derived fromJonsson (1982), and is based on the definition of the probability distribution function ofmyoelectric signal amplitude. According to Jonsson, the static, maximum peak andmedian load levels can be identified on the amplitude distribution cumulative curves.Studies by Bjórksten and Jonsson (1977) on resistance to fatigue in exercises repeatedfor varying lengths of time, led to the definition of maximum limits for static, medianand peak load values that may be summarized as follows: static load should not exceed2-5% of the maximum voluntary contraction, median load 10-14% and peak load50-70%.In the present study we examined eight groups of muscles, i.e., right upper trapezius,right deltoideus, right biceps, right forearm muscles (epicondyle), right forearm muscles(epitrochlea), right lumbar erector, first interosseus dorsalis of the right hand, left uppertrapezius.Myoelectric signals were obtained using superficial electrodes connected to atelemetric electromyograph. The signal was then rectified and analogically integratetiand transmitted to an IBM/AT personal computer. The software specially developedto obtain and process the signals in rea) time also included simultaneous on-linevisualization of the eight electromyoelectrographic signals. Fina) graphicrepresentation and subsequent statistica) analysis were performed at the enti of theexperimental session on the memorized data.For each subject, myoelectric activity of each muscle was preliminarily recordedduring maximum voluntary contraction (MVC) against resistance. Figure 2 illustratesthe operation required to record the MVC of the epicondyle muscle group.
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