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EMG trapezius muscle activity pattern in string players: Part II—Influences of basic body awareness therapy on the violin playing technique
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International Journal of Industrial Ergonomics 33 (2004) 357–367
EMG trapezius muscle activity pattern in string players: Part II—Influences of basic body awareness therapy on the violin playing technique Anncristine Fjellman-Wiklunda,*, Helena Gripb, Hans Anderssonb, Jan Stefan Karlssonb, Gunnevi Sundelina b
a ( Sweden Department of Community Medicine and Rehabilitation, Physiotherapy, Umea( University, SE-901 87 Umea, ( Sweden Department of Biomedical Engineering and Informatics, University Hospital of Northern Sweden, SE-901 85 Umea,
Received 16 June 2003; received in revised form 21 October 2003; accepted 23 October 2003
Abstract This study used electromyography (EMG) to investigate if violinists could play with a greater variation in the trapezius muscle activity pattern after an 8-week training program with Basic Body Awareness Therapy (Basic BAT), as compared with a reference group. Five professional orchestra violinists who trained Basic BAT were compared to nine violinists working as violin teachers or music students at higher education level who did not take part in any training. The trapezius muscle activity, while playing a piece of music, was monitored by bilateral surface EMG before and after the 8-week training period. Exposure Variation Analysis (EVA) and Principal Component Analysis (PCA) were used for the EMG analyses. No significant differences were found in the trapezius muscle activation between the Basic BATtrained group and the reference group. The training group perceived positive changes in breathing, muscular tension, postural control and concentration mainly during practice sessions. Musicians might benefit from practicing warming up, taking regular pauses to recover and proper working technique in activities other than playing an instrument. Relevance to industry Proper work technique, work postures and movements are important to prevent neck and shoulder problems. This study shows a pedagogical approach to modify posture and bodily reactions during work tasks. r 2003 Elsevier B.V. All rights reserved. Keywords: Exposure variation analysis; Musician; Musculoskeletal; Body–mind; Basic body awareness therapy
1. Introduction A good working technique is important for preventing neck and shoulder problems. Teaching *Corresponding author. E-mail address: anncristine.fjellman-wiklund@physiother. umu.se (A. Fjellman-Wiklund).
proper work postures and movements should be given a high priority (Kilbom and Persson, 1987). One of the goals of music pedagogy is to find an optimal playing technique posture for each musician to allow efficient playing with a minimum of tension in the muscles involved during playing (Levy et al., 1992). In practical sessions, special body-oriented techniques, playing and working
0169-8141/$ - see front matter r 2003 Elsevier B.V. All rights reserved. doi:10.1016/j.ergon.2003.10.008
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with optimal postures and special movements have been recommended for university music students (Spaulding, 1988; Brandfonbrener and Kjelland, 2002). However, there is limited scientific evidence supporting these approaches (Dommerholt et al., 1998). The Alexander technique (Alexander, 1932), Basic Body Awareness Therapy (Basic BAT) (Roxendal, 1985), Feldenkrais pedagogy (Feldenkrais, 1972), and Tai Chi Chuan (Cheng, Man Ch’ing and Smith, 1967) are some methods frequently used by musicians. For university music students in Sweden, one of the most common techniques is the Basic BAT. The body-oriented techniques are based on a holistic perspective— core elements are body and movement awareness and the techniques focus on the experience of body-as-a-whole rather than specific separate movements (Malmgren Olsson et al., 2001). The method, Basic BAT, was established in Scandinavia by Roxendal (1985), inspired by Feldenkrais pedagogy and Dropsy’s movement system (1975). Dropsy, in his turn, was influenced by both western traditions such as the Alexander technique and the Feldenkrais pedagogy and eastern traditions of Tai Chi Chuan and Zen meditation. Originally Basic BAT was developed as a treatment modality within psychiatric physiotherapy (Roxendal, 1985; Roxendal and Winberg, 2002) and it is now also utilised for patients with chronic pain and musculoskeletal disorders (Grahn et al., 1998; Ahlgren et al., 2001; Malmgren Olsson et al., 2001). The aim of the Basic BAT is to improve posture, by working with the relation to the ground (grounding) and the postural line and total co-ordination and to integrate breathing with movements (Roxendal and Winberg, 2002). Dropsy (1975) proposed that changes in the pattern of muscle activity of different movements might reduce muscle tension and pain. This has also been the main thought when educating musicians in body-oriented techniques. The practical sessions have been occasional and irregular in many cases. From a motor control perspective one might question if it is possible to achieve changes in movement pattern and muscle activity on the basis of such occasional sessions. Electromyography (EMG) analyses of the muscle activity during neck and shoulder work offer
important information about work exposure (Mathiassen and Winkel, 1996). The Exposure Variation Analysis (EVA) method was developed to quantify the EMG muscle activity in both the amplitude distribution and in the duration in defined domains. In Part I of this study (FjellmanWiklund et al.), we showed individual differences for period distributions on the left trapezius and amplitude distribution on the right trapezius, among 12 string players by making a principal component analysis (PCA) of the EVA data. We also showed that EVA data were reproducible for the string players which all performed two playing sessions with a 10-week interval. Therefore, the EVA method could possibly be used for evaluation of playing technique. The purpose of the present study was to investigate, using EVA, if a group of violinists could change their trapezius muscle activity pattern after an 8-week training program with Basic BAT as compared with a non-training reference group.
2. Subjects and methods 2.1. Subjects Fifteen violinists, in the northern part of Sweden, participated in the study, five in a training group and 10 in a reference group. Nine of the references were in repeated measurements used for intra-individual comparisons of playing technique in Part I of this study. To make it possible for the working musicians to participate in the program during work time, the training group was chosen among professional orchestra violinists at the same work place. To the reference group, violin teachers from municipal music schools and violin music students at higher-level education were invited. In the training group there were two women and three men with the mean age 37.6 (SD 9.0) and in the reference group there were six women and four men with the mean age 36.6 (SD 14.0). One woman in the reference group dropped out due to personal reasons, at the posttraining measurement. Thus, a total of 14 violinists completed the study. All violinists were right
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handed. Both the training group and the reference group started playing at mean age of 8 years (SD 1.0 for both groups). The total mean playing time for the training group was 30 h/week (SD 3.5) and for the reference group 25 h/week (SD 10.8). The average attendance rate for the whole Basic BAT training group was 70%. 2.2. Study design The EMG activity in the trapezius muscle was recorded bilaterally during performing a standardised piece of music, before and after an 8-week period of Basic BAT. The EMG testing order was the same for all subjects at the playing session before and after the intervention. After the training period, all subjects in the Basic BAT training group were interviewed about their perceptions of the training. Information about the study was given both in written form and orally to the subjects, and they participated after informed consent. The Ethical Committee, Faculty of Medicine, Umea( University, Umea( , Sweden approved the study. 2.3. Intervention—basic BAT training group A Basic BAT program was designed and supervised by a physiotherapist specialised in the method. The aim of the training program was to vary playing-related muscle activity and to better co-ordinate work and rest phases during work by practising Basic BAT training. The training period lasted for 8 weeks, with sessions once a week, 90 min each time. The length of the training period was based on experience from how body awareness technique is practised at music universities. The training was included in the workday and was performed at the violinists’ work place where the training was practised. All sessions started with a short warm up, followed by specific exercises and ended with a 15-min verbal reflection and a summary of individual experiences. To avoid feelings of stress and competition during the training session, none of the movements included training with a violin. The program consisted of basic, simple movements to restore postural balance, grounding, co-ordination and to free the
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breathing (Roxendal, 1985; Roxendal and Winberg, 2002). The movements were performed in supine, sitting, standing and walking positions. The program also included special massage techniques performed by the subjects on each other during pairwise exercises. Mental awareness was integrated during the whole training process, which means that turning the attention both to the doing of the exercises and to what was experienced in the movements was central. 2.4. Non-training group The reference group did not perform any special training during the time the intervention took place. They were asked to live as usual and not to change their ordinary physical activity habits. 2.5. Interview A semi-structured interview was performed individually with all subjects in the training group. This was done in order to evaluate their opinions of the training program, i.e., the length of the program and if it was difficult to fit into the workday. The subjects were also asked about their perceptions, such as muscle tension and tiredness during and between the training sessions. 2.6. Surface electromyography The methods of using electromyography to obtain and process bilaterally surface EMG signals, reference voluntary contractions (RVEs) and resting EMG activities from the left and right upper trapezius muscles are presented in Part I of this study (Fjellman-Wiklund et al.). The same methods were used in the present study. 2.6.1. Playing procedure Each subject was given 4–5 min of warm-up time on his/her own violin and then rested for 2 min to avoid fatigue. The subjects were required to perform a musical excerpt during which EMG signals from left and right trapezius was recorded. The piece of music, which lasted for 7 min, was a selection from a Mozart Solo-Violin concert. The subjects were not familiar with the music and had
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not practised it before the EMG measurement. To minimise stress during the recording, no metronome was used for the tempo, but the subjects could adjust the tempo indicated by the written music.
playing sessions were calculated (PCA shift), using principal components contributing to more than 80% of total variance.
3. Results 2.7. EMG data acquisition and analyses 3.1. Exposure variation analysis The EMG activity recording was analysed with the EVA, which quantifies the relative time of the EMG activity in both the amplitude distribution and the duration in defined domains (Mathiassen and Winkel, 1996) as presented in Part I of this study (Fjellman-Wiklund et al.). 2.8. Statistical analyses All statistical analyses were performed using SPSS for Windows (version 9.0 SPSS Inc., Chicago, IL, USA) and MATLABs. EVA data from the Basic BAT training and the reference group were tested with a non-parametric test. The Mann–Whitney test was used to investigate differences, in mean, between the independent groups. The Wilcoxon signed-rank test was used to test if any changes in mean were significant for the training group before and after the training. The Wilcoxon signed-rank test was used to test if changes in PCA shift, in mean, were significant for the training group before and after the training. A probability level of po0:05 was considered as statistically significant. 2.8.1. Principal component analysis PCA was used in order to classify the EMG activity pattern of the subjects on a group level. The method is presented in Part I of this study (Fjellman-Wiklund et al.). In order to study effects from amplitude and period separately, PCA was performed on the marginal distributions containing six (summing over period) and seven (summing over amplitude) variables. PCA was performed on the right trapezius data and the left trapezius data separately. By plotting the principal components that accounts for most of the variance, an overview was received, of how the subjects’ data differ with respect to their EMG activity pattern. For each subject, the Euclidean distances between two
EMG recordings of the left and the right trapezius, before and after the Basic BAT, were used for the analysis. EVA patterns for one subject from the Basic BAT training group and one from the reference group are used as representative examples in Figs. 1 and 2. Generally for the violinists, period times were longer for the left trapezius than for the right trapezius. Both the left and the right trapezius muscle were characterised by activity mainly in the range 3–50% RVE (right trapezius) and 3–25% RVE (left trapezius), with the main duration in the range 1–15 s (left trapezius) and l–7 s (right trapezius). There was hardly any muscle activation below 1.67% RVE, which suggests that there were almost no short, unconscious interruptions in EMG trapezius activity, so called gaps. Statistics indicated that no difference was found in the variability of the trapezius muscle activity pattern between the Basic BAT training group and the reference group, before the intervention (left trapezius, p ¼ 0:4; right trapezius, p ¼ 0:2) or after the intervention (left trapezius, p ¼ 0:9; right trapezius, p ¼ 0:7). There was no difference found in the training group before and after the training period (left trapezius, p ¼ 0:4; right trapezius, p ¼ 0:7). However, EVA patterns differed from individual to individual as seen when comparing EVA from the violinists in Figs. 1 and 2. 3.2. Principal component analysis The principal component analyses were made on the marginal period distribution (time) and the marginal amplitude distribution. The analyses resulted in six and seven principal components (PCs). For the marginal amplitude distribution, three PCs were needed to describe 80% of the total variance, while two PCs explained 80% of the
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Fig. 1. EVA for a violinist in the training group.
marginal period distribution (Table 1). The spread of the training group and the reference group are illustrated in Figs. 3 and 4 by plotting the dominating PCs (PC1 and PC2). Fig. 3 illustrates the period distribution and Fig. 4 the amplitude distribution for the total group of violinists, before and after the training period, for the left and the right trapezius. To conclude, as indicated by the figures, there were individual differences in muscle activity patterns. Dominating period times varied from very short to very long (Fig. 3) between subjects. Amplitude levels (Fig. 4) also varied, even
though most of the subjects showed low or moderate amplitude levels (Q2 and Q3). Generally, the load on the left trapezius was more static (longer period times) on a lower load (lower amplitude levels) than on the right trapezius. 3.2.1. Period distribution The PCs can be explained by studying the component loadings in Table 2. Roughly, the PC plots in Fig. 3 can be divided into four quadrants, Q1–Q4, describing which periods that dominated a subject’s pattern, extending from short (Q1) to
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Fig. 2. EVA for a violinist in the reference group.
Table 1 Percent of total variability of the amplitude and period marginal distributions explained by PCs PCs
1 2 3 4 5 6 7
Amplitude (%)
Period (%)
Left trapezius
Right trapezius
Left trapezius
Right trapezius
42.8 25.8 16.9 8.7 4.7 1.1 0.0
42.2 26.7 16.4 10.1 3.3 1.2 0.0
60.8 22.9 9.0 6.1 1.2 0.0 —
57.5 28.5 7.8 4.1 2.1 0.0 —
The PCs contributing to more than or equal to 80% of the total variance are in italics.
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long (Q4) periods. Subjects in Q1 had mainly short periodso1 s. In Q2, periods of 1–7 s (left trapezius) or l–3 s (right trapezius) dominated. In Q3, periods of 7–15 s (left trapezius) or 3–7 s (right trapezius) dominated, while subjects in Q4 had relatively long periods, i.e., more than 15 s (left trapezius) or more than 7 s (right trapezius).
Fig. 3. PCA of period distribution for violinists.
3.2.2. Amplitude distribution Component loadings in Table 3 indicated that the PC plots over amplitude distributions (Fig. 4) can be split into four quadrants. Q1 describes subjects with mainly low amplitude levels, i.e., less than 10% RVE, Q2 describes subjects with amplitude levels, of 3–23% (left trapezius) or 10– 23% RVE (right trapezius), and Q3 describes moderate levels, mainly 10–50% RVE (left trapezius) or 23–50% RVE (right trapezius) and Q4 describes subjects with mostly high amplitude levels, i.e., more than 50% RVE. 3.3. Shift in training and reference group No significant group differences in shift (defined as the Euclidean distance in the PC plot between first and second playing session) were found, either in amplitude (p ¼ 0:06 for left trapezius and 0.52 for right trapezius) or in period (p ¼ 0:08 left trapezius and p ¼ 0:61 right trapezius). 3.4. Perceptions of basic BAT
Fig. 4. PCA of amplitude distribution for violinists.
All participants in the Basic BAT training group were positive to the program and to having the training integrated into the working day. Some of
Table 2 Component loadings for period marginal distribution of the left and the right trapezius muscle with PCs contributing to more than or equal to 80% of the total variance in the period data Interval
1 2 3 4 5 6
Period (s)
0–0.3 0.3–1 1–3 3–7 7–15 X15
Left trapezius
Right trapezius
PC1
PC2
PC1
PC2
0.42 0.50 0.48 0.03 0.35 0.46
0.23 0.07 0.17 0.79 0.40 0.36
0.40 0.49 0.26 0.40 0.44 0.42
0.43 0.27 0.63 0.37 0.34 0.32
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Table 3 Component loadings for amplitude marginal distribution for the left and the right trapezius muscle with PCs contributing to more than or equal to 80% of the total variance in the amplitude data Interval
1 2 3 4 5 6 7
Amplitude (% RVE)
0–1 1–3 3.3–10 10–23.3 23.3–50 50–103 103–210
Left trapezius
Right trapezius
PC1
PC2
PC3
PC1
PC2
PC3
0.52 0.50 0.48 0.09 0.40 0.24 0.15
0.16 0.15 0.03 0.51 0.05 0.60 0.57
0.16 0.16 0.12 0.59 0.64 0.16 0.39
0.32 0.49 0.51 0.20 0.36 0.41 0.25
0.23 0.26 0.20 0.48 0.32 0.46 0.54
0.32 0.27 0.03 0.56 0.59 0.02 0.39
the violinists perceived a greater harmony and stillness, a freer breathing during sessions, and better concentration prior to performing. Some perceived that they could handle muscular tension in a better way and that they had an improved posture. Some also felt an awareness of interpreting signals from the body. The group suggested a longer training period than 8 weeks and more training sessions than once a week during intense rehearsal and performance periods since they experienced that the Basic BAT helped them to cope with intense work periods.
4. Discussion 4.1. The basic BAT intervention The present study found no significant changes in the EMG trapezius muscle activity pattern in the Basic BAT training group. However, the group experienced positive perceptions of breathing, muscular tension, postural control and concentration, mainly during practice sessions. The 8-week training period of Basic BAT might be long enough for the violinists to experience positive bodily perceptions but not long enough to change the EMG muscle activity pattern. The musicians would probably benefit from a longer training period, which also was suggested by the subjects in the Basic BAT training group in the evaluation of this intervention. Roxendal and Winberg (2002) have made comments concerning the length of the
Basic BAT training period of a clinical intervention in string musicians with chronic pain. They concluded that good results were achieved when practising individual Basic BAT during 3–8 months with 32 sessions as mean. The string musicians in that clinical intervention were chronic pain patients suffering from disorders up to 15 years and had been treated with other modalities before the Basic BAT, which was not the case in our study. The subjects in the present study were not diagnosed as pain patients and they were all working at the time for the intervention. Studies evaluating practice with various bodyoriented techniques among musicians have found positive changes in perceptions of muscle tension and movement pattern (Dommerholt et al., 1998; Brandfonbrener and Kjelland, 2002; Roxendal and Winberg, 2002). The results are mainly based on clinical assessments while very few studies have used EMG in the evaluation of muscle activity. Changes in EMG activity in the trapezius muscle after practising Basic BAT have been shown in a study on the effects of dynamic training programs for women with work-related trapezius myalgia (Ahlgren et al., 2001). The study indicated that women who practised co-ordination (Basic BAT) of the neck and shoulder muscles improved their ability to relax and to utilise pauses as compared with women who trained strength or endurance. Furthermore, the study had a rehabilitation scope and focused on pain and the EMG signal was analysed with respect to the signal–amplitude ratio, which was not the case in our study.
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4.2. Training interventions in musicians Time limitation was a reason for not attending the intervention in the present study. Although the training sessions were included in the work schedule, which was perceived as positive, it was added as ‘‘one more work task to do’’. This was also found by Brandfonbrener (1997) who studied the problems with implementing and maintaining a prevention program among orchestra musicians. A program with lectures on musculoskeletal education and specific exercises for the upper extremity was implemented in orchestra musicians with three visits over a 1-year period. The study had a very low attendance rate, almost 40% of the participants dropped out. The reasons for the withdrawals were due to time limitations and a feeling that the program was ‘‘just one thing too much’’. If management were to provide time for exercise the musicians would endorse the training. The dropouts also thought that even thinking about injuries was negative in itself, which might make them more vulnerable to disorders. 4.3. The work technique Concepts of motor learning and motor control (Shumway-Cook and Woollacott, 2001) and interventions over a shorter period suggests that the best time to prevent musicians’ disorders seems to be during the early stages of education (Brandfonbrener and Kjelland, 2002). Prevention from the earliest lessons implements efficient performance techniques, postural habits, a positive attitude and a healthy lifestyle. This highlights how important it is that music teachers instruct their students in proper playing technique at an early age and that teachers learn how to address postural and movement faults before they lead to injury (Medoff, 1999). Brandfonbrener (1998) questions whether it is a health benefit or a hazard to have played a musical instrument from early childhood starting before the body is full-grown. The partial answer lies in how the instrument and player interact, the technique, the player’s natural equipment and the quality of the teaching. Brandfonbrener (1998) emphasises that there is a potential for the music teacher to influence, good
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or bad, the musical life and development of a young musician. She further argues that there are many considerations in selecting a music teacher. Therefore, it should be a mutual process between the teacher, the music student and for the young student also the parents. Questions of the music teacher’s musical competence are vital, but questions of communication, teaching style and mutually compatible goals are equally important. Later on when the playing technique has been established, musicians might benefit more from practising proper warming up before playing, taking regular pauses to recover and a good working technique in activities other than playing an instrument (Spaulding, l988). These activities could also be practised in Basic BAT. A good work environment could further be improved by ergonomic work place factors such as comfortable chairs and adjustable music stands. Aspects of the total practice time and a good psychosocial work environment must also be considered. 4.4. Methodological considerations In this study, EMG measurements were made on the trapezius muscle bilaterally, based on the fact that the trapezius muscle is active in violin playing (Philipson et al., 1990; Berque and Gray, 2002), and it seems to be more vulnerable to muscle tension and pain than other neck and shoulder muscles (Vasseljen et al., 2001). A study design with EMG measurements of other muscles important to violin playing could have shown if there were differences in the muscle activity pattern of other shoulder muscles as well. Berque and Gray (2002) have proposed that violinists with a low amount of neck and shoulder pain may redistribute the load to other synergistic muscles. Their proposal is based on results by Palmerud et al. (1998), who showed that it is possible to reduce the muscle activity in the upper part of the trapezius muscle without changing the arm position or the hand load. On the other hand, reducing the trapezius muscle activity may increase the muscle activity in other shoulder muscles, mainly the rhomboid major and minor, the transverse part of the trapezius, the deltoideus and the serratus anterior.
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5. Conclusions Overall, this study found no differences in muscle activity between a group of violinists practising a body awareness technique and a non training group. Still, the Basic BAT-trained group perceived positive changes in breathing, muscular tension, postural control and concentration mainly during practise sessions. This emphasises the importance of music teachers instructing their students in a proper playing technique since it seems hard to influence once it has become established. Good postures and playing techniques have to be learned while playing the instrument but might also be emphasized in training modalities such as Basic BAT. However, a longer training period is probably necessary to affect the EMG muscle activity pattern. Practising proper warming up, taking regular pauses to recover and using good working techniques in activities other than playing the instrument are also important. Conclusions from this study must be drawn with care because of the relatively small sample sizes. Larger groups of string musicians need to be studied to allow for more accurate conclusions.
Acknowledgements The authors would like to thank Arbetsmarkna. akringsaktiebolag AFA, The Foundation dens fors. of Mutual Accident Insurance Company ‘‘Land . och Sjo’’, The Kempe foundation and The Swedish Association of Registered Physiotherapist for financial support. Thanks also to the phy. siotherapists Yvonne Bergstrom, Maria Bjurman and Virpi Jylh.a for valuable assistance in collecting the data and to Maria Wiklund for skilled guidance of the body awareness therapy.
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EMG trapezius muscle activity pattern in string players: Part II—Influences of basic body awareness therapy on the violin playing technique Anncristine Fjellman-Wiklunda,*, Helena Gripb, Hans Anderssonb, Jan Stefan Karlssonb, Gunnevi Sundelina b
a ( Sweden Department of Community Medicine and Rehabilitation, Physiotherapy, Umea( University, SE-901 87 Umea, ( Sweden Department of Biomedical Engineering and Informatics, University Hospital of Northern Sweden, SE-901 85 Umea,
Received 16 June 2003; received in revised form 21 October 2003; accepted 23 October 2003
Abstract This study used electromyography (EMG) to investigate if violinists could play with a greater variation in the trapezius muscle activity pattern after an 8-week training program with Basic Body Awareness Therapy (Basic BAT), as compared with a reference group. Five professional orchestra violinists who trained Basic BAT were compared to nine violinists working as violin teachers or music students at higher education level who did not take part in any training. The trapezius muscle activity, while playing a piece of music, was monitored by bilateral surface EMG before and after the 8-week training period. Exposure Variation Analysis (EVA) and Principal Component Analysis (PCA) were used for the EMG analyses. No significant differences were found in the trapezius muscle activation between the Basic BATtrained group and the reference group. The training group perceived positive changes in breathing, muscular tension, postural control and concentration mainly during practice sessions. Musicians might benefit from practicing warming up, taking regular pauses to recover and proper working technique in activities other than playing an instrument. Relevance to industry Proper work technique, work postures and movements are important to prevent neck and shoulder problems. This study shows a pedagogical approach to modify posture and bodily reactions during work tasks. r 2003 Elsevier B.V. All rights reserved. Keywords: Exposure variation analysis; Musician; Musculoskeletal; Body–mind; Basic body awareness therapy
1. Introduction A good working technique is important for preventing neck and shoulder problems. Teaching *Corresponding author. E-mail address: anncristine.fjellman-wiklund@physiother. umu.se (A. Fjellman-Wiklund).
proper work postures and movements should be given a high priority (Kilbom and Persson, 1987). One of the goals of music pedagogy is to find an optimal playing technique posture for each musician to allow efficient playing with a minimum of tension in the muscles involved during playing (Levy et al., 1992). In practical sessions, special body-oriented techniques, playing and working
0169-8141/$ - see front matter r 2003 Elsevier B.V. All rights reserved. doi:10.1016/j.ergon.2003.10.008
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with optimal postures and special movements have been recommended for university music students (Spaulding, 1988; Brandfonbrener and Kjelland, 2002). However, there is limited scientific evidence supporting these approaches (Dommerholt et al., 1998). The Alexander technique (Alexander, 1932), Basic Body Awareness Therapy (Basic BAT) (Roxendal, 1985), Feldenkrais pedagogy (Feldenkrais, 1972), and Tai Chi Chuan (Cheng, Man Ch’ing and Smith, 1967) are some methods frequently used by musicians. For university music students in Sweden, one of the most common techniques is the Basic BAT. The body-oriented techniques are based on a holistic perspective— core elements are body and movement awareness and the techniques focus on the experience of body-as-a-whole rather than specific separate movements (Malmgren Olsson et al., 2001). The method, Basic BAT, was established in Scandinavia by Roxendal (1985), inspired by Feldenkrais pedagogy and Dropsy’s movement system (1975). Dropsy, in his turn, was influenced by both western traditions such as the Alexander technique and the Feldenkrais pedagogy and eastern traditions of Tai Chi Chuan and Zen meditation. Originally Basic BAT was developed as a treatment modality within psychiatric physiotherapy (Roxendal, 1985; Roxendal and Winberg, 2002) and it is now also utilised for patients with chronic pain and musculoskeletal disorders (Grahn et al., 1998; Ahlgren et al., 2001; Malmgren Olsson et al., 2001). The aim of the Basic BAT is to improve posture, by working with the relation to the ground (grounding) and the postural line and total co-ordination and to integrate breathing with movements (Roxendal and Winberg, 2002). Dropsy (1975) proposed that changes in the pattern of muscle activity of different movements might reduce muscle tension and pain. This has also been the main thought when educating musicians in body-oriented techniques. The practical sessions have been occasional and irregular in many cases. From a motor control perspective one might question if it is possible to achieve changes in movement pattern and muscle activity on the basis of such occasional sessions. Electromyography (EMG) analyses of the muscle activity during neck and shoulder work offer
important information about work exposure (Mathiassen and Winkel, 1996). The Exposure Variation Analysis (EVA) method was developed to quantify the EMG muscle activity in both the amplitude distribution and in the duration in defined domains. In Part I of this study (FjellmanWiklund et al.), we showed individual differences for period distributions on the left trapezius and amplitude distribution on the right trapezius, among 12 string players by making a principal component analysis (PCA) of the EVA data. We also showed that EVA data were reproducible for the string players which all performed two playing sessions with a 10-week interval. Therefore, the EVA method could possibly be used for evaluation of playing technique. The purpose of the present study was to investigate, using EVA, if a group of violinists could change their trapezius muscle activity pattern after an 8-week training program with Basic BAT as compared with a non-training reference group.
2. Subjects and methods 2.1. Subjects Fifteen violinists, in the northern part of Sweden, participated in the study, five in a training group and 10 in a reference group. Nine of the references were in repeated measurements used for intra-individual comparisons of playing technique in Part I of this study. To make it possible for the working musicians to participate in the program during work time, the training group was chosen among professional orchestra violinists at the same work place. To the reference group, violin teachers from municipal music schools and violin music students at higher-level education were invited. In the training group there were two women and three men with the mean age 37.6 (SD 9.0) and in the reference group there were six women and four men with the mean age 36.6 (SD 14.0). One woman in the reference group dropped out due to personal reasons, at the posttraining measurement. Thus, a total of 14 violinists completed the study. All violinists were right
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handed. Both the training group and the reference group started playing at mean age of 8 years (SD 1.0 for both groups). The total mean playing time for the training group was 30 h/week (SD 3.5) and for the reference group 25 h/week (SD 10.8). The average attendance rate for the whole Basic BAT training group was 70%. 2.2. Study design The EMG activity in the trapezius muscle was recorded bilaterally during performing a standardised piece of music, before and after an 8-week period of Basic BAT. The EMG testing order was the same for all subjects at the playing session before and after the intervention. After the training period, all subjects in the Basic BAT training group were interviewed about their perceptions of the training. Information about the study was given both in written form and orally to the subjects, and they participated after informed consent. The Ethical Committee, Faculty of Medicine, Umea( University, Umea( , Sweden approved the study. 2.3. Intervention—basic BAT training group A Basic BAT program was designed and supervised by a physiotherapist specialised in the method. The aim of the training program was to vary playing-related muscle activity and to better co-ordinate work and rest phases during work by practising Basic BAT training. The training period lasted for 8 weeks, with sessions once a week, 90 min each time. The length of the training period was based on experience from how body awareness technique is practised at music universities. The training was included in the workday and was performed at the violinists’ work place where the training was practised. All sessions started with a short warm up, followed by specific exercises and ended with a 15-min verbal reflection and a summary of individual experiences. To avoid feelings of stress and competition during the training session, none of the movements included training with a violin. The program consisted of basic, simple movements to restore postural balance, grounding, co-ordination and to free the
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breathing (Roxendal, 1985; Roxendal and Winberg, 2002). The movements were performed in supine, sitting, standing and walking positions. The program also included special massage techniques performed by the subjects on each other during pairwise exercises. Mental awareness was integrated during the whole training process, which means that turning the attention both to the doing of the exercises and to what was experienced in the movements was central. 2.4. Non-training group The reference group did not perform any special training during the time the intervention took place. They were asked to live as usual and not to change their ordinary physical activity habits. 2.5. Interview A semi-structured interview was performed individually with all subjects in the training group. This was done in order to evaluate their opinions of the training program, i.e., the length of the program and if it was difficult to fit into the workday. The subjects were also asked about their perceptions, such as muscle tension and tiredness during and between the training sessions. 2.6. Surface electromyography The methods of using electromyography to obtain and process bilaterally surface EMG signals, reference voluntary contractions (RVEs) and resting EMG activities from the left and right upper trapezius muscles are presented in Part I of this study (Fjellman-Wiklund et al.). The same methods were used in the present study. 2.6.1. Playing procedure Each subject was given 4–5 min of warm-up time on his/her own violin and then rested for 2 min to avoid fatigue. The subjects were required to perform a musical excerpt during which EMG signals from left and right trapezius was recorded. The piece of music, which lasted for 7 min, was a selection from a Mozart Solo-Violin concert. The subjects were not familiar with the music and had
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not practised it before the EMG measurement. To minimise stress during the recording, no metronome was used for the tempo, but the subjects could adjust the tempo indicated by the written music.
playing sessions were calculated (PCA shift), using principal components contributing to more than 80% of total variance.
3. Results 2.7. EMG data acquisition and analyses 3.1. Exposure variation analysis The EMG activity recording was analysed with the EVA, which quantifies the relative time of the EMG activity in both the amplitude distribution and the duration in defined domains (Mathiassen and Winkel, 1996) as presented in Part I of this study (Fjellman-Wiklund et al.). 2.8. Statistical analyses All statistical analyses were performed using SPSS for Windows (version 9.0 SPSS Inc., Chicago, IL, USA) and MATLABs. EVA data from the Basic BAT training and the reference group were tested with a non-parametric test. The Mann–Whitney test was used to investigate differences, in mean, between the independent groups. The Wilcoxon signed-rank test was used to test if any changes in mean were significant for the training group before and after the training. The Wilcoxon signed-rank test was used to test if changes in PCA shift, in mean, were significant for the training group before and after the training. A probability level of po0:05 was considered as statistically significant. 2.8.1. Principal component analysis PCA was used in order to classify the EMG activity pattern of the subjects on a group level. The method is presented in Part I of this study (Fjellman-Wiklund et al.). In order to study effects from amplitude and period separately, PCA was performed on the marginal distributions containing six (summing over period) and seven (summing over amplitude) variables. PCA was performed on the right trapezius data and the left trapezius data separately. By plotting the principal components that accounts for most of the variance, an overview was received, of how the subjects’ data differ with respect to their EMG activity pattern. For each subject, the Euclidean distances between two
EMG recordings of the left and the right trapezius, before and after the Basic BAT, were used for the analysis. EVA patterns for one subject from the Basic BAT training group and one from the reference group are used as representative examples in Figs. 1 and 2. Generally for the violinists, period times were longer for the left trapezius than for the right trapezius. Both the left and the right trapezius muscle were characterised by activity mainly in the range 3–50% RVE (right trapezius) and 3–25% RVE (left trapezius), with the main duration in the range 1–15 s (left trapezius) and l–7 s (right trapezius). There was hardly any muscle activation below 1.67% RVE, which suggests that there were almost no short, unconscious interruptions in EMG trapezius activity, so called gaps. Statistics indicated that no difference was found in the variability of the trapezius muscle activity pattern between the Basic BAT training group and the reference group, before the intervention (left trapezius, p ¼ 0:4; right trapezius, p ¼ 0:2) or after the intervention (left trapezius, p ¼ 0:9; right trapezius, p ¼ 0:7). There was no difference found in the training group before and after the training period (left trapezius, p ¼ 0:4; right trapezius, p ¼ 0:7). However, EVA patterns differed from individual to individual as seen when comparing EVA from the violinists in Figs. 1 and 2. 3.2. Principal component analysis The principal component analyses were made on the marginal period distribution (time) and the marginal amplitude distribution. The analyses resulted in six and seven principal components (PCs). For the marginal amplitude distribution, three PCs were needed to describe 80% of the total variance, while two PCs explained 80% of the
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Fig. 1. EVA for a violinist in the training group.
marginal period distribution (Table 1). The spread of the training group and the reference group are illustrated in Figs. 3 and 4 by plotting the dominating PCs (PC1 and PC2). Fig. 3 illustrates the period distribution and Fig. 4 the amplitude distribution for the total group of violinists, before and after the training period, for the left and the right trapezius. To conclude, as indicated by the figures, there were individual differences in muscle activity patterns. Dominating period times varied from very short to very long (Fig. 3) between subjects. Amplitude levels (Fig. 4) also varied, even
though most of the subjects showed low or moderate amplitude levels (Q2 and Q3). Generally, the load on the left trapezius was more static (longer period times) on a lower load (lower amplitude levels) than on the right trapezius. 3.2.1. Period distribution The PCs can be explained by studying the component loadings in Table 2. Roughly, the PC plots in Fig. 3 can be divided into four quadrants, Q1–Q4, describing which periods that dominated a subject’s pattern, extending from short (Q1) to
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Fig. 2. EVA for a violinist in the reference group.
Table 1 Percent of total variability of the amplitude and period marginal distributions explained by PCs PCs
1 2 3 4 5 6 7
Amplitude (%)
Period (%)
Left trapezius
Right trapezius
Left trapezius
Right trapezius
42.8 25.8 16.9 8.7 4.7 1.1 0.0
42.2 26.7 16.4 10.1 3.3 1.2 0.0
60.8 22.9 9.0 6.1 1.2 0.0 —
57.5 28.5 7.8 4.1 2.1 0.0 —
The PCs contributing to more than or equal to 80% of the total variance are in italics.
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long (Q4) periods. Subjects in Q1 had mainly short periodso1 s. In Q2, periods of 1–7 s (left trapezius) or l–3 s (right trapezius) dominated. In Q3, periods of 7–15 s (left trapezius) or 3–7 s (right trapezius) dominated, while subjects in Q4 had relatively long periods, i.e., more than 15 s (left trapezius) or more than 7 s (right trapezius).
Fig. 3. PCA of period distribution for violinists.
3.2.2. Amplitude distribution Component loadings in Table 3 indicated that the PC plots over amplitude distributions (Fig. 4) can be split into four quadrants. Q1 describes subjects with mainly low amplitude levels, i.e., less than 10% RVE, Q2 describes subjects with amplitude levels, of 3–23% (left trapezius) or 10– 23% RVE (right trapezius), and Q3 describes moderate levels, mainly 10–50% RVE (left trapezius) or 23–50% RVE (right trapezius) and Q4 describes subjects with mostly high amplitude levels, i.e., more than 50% RVE. 3.3. Shift in training and reference group No significant group differences in shift (defined as the Euclidean distance in the PC plot between first and second playing session) were found, either in amplitude (p ¼ 0:06 for left trapezius and 0.52 for right trapezius) or in period (p ¼ 0:08 left trapezius and p ¼ 0:61 right trapezius). 3.4. Perceptions of basic BAT
Fig. 4. PCA of amplitude distribution for violinists.
All participants in the Basic BAT training group were positive to the program and to having the training integrated into the working day. Some of
Table 2 Component loadings for period marginal distribution of the left and the right trapezius muscle with PCs contributing to more than or equal to 80% of the total variance in the period data Interval
1 2 3 4 5 6
Period (s)
0–0.3 0.3–1 1–3 3–7 7–15 X15
Left trapezius
Right trapezius
PC1
PC2
PC1
PC2
0.42 0.50 0.48 0.03 0.35 0.46
0.23 0.07 0.17 0.79 0.40 0.36
0.40 0.49 0.26 0.40 0.44 0.42
0.43 0.27 0.63 0.37 0.34 0.32
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Table 3 Component loadings for amplitude marginal distribution for the left and the right trapezius muscle with PCs contributing to more than or equal to 80% of the total variance in the amplitude data Interval
1 2 3 4 5 6 7
Amplitude (% RVE)
0–1 1–3 3.3–10 10–23.3 23.3–50 50–103 103–210
Left trapezius
Right trapezius
PC1
PC2
PC3
PC1
PC2
PC3
0.52 0.50 0.48 0.09 0.40 0.24 0.15
0.16 0.15 0.03 0.51 0.05 0.60 0.57
0.16 0.16 0.12 0.59 0.64 0.16 0.39
0.32 0.49 0.51 0.20 0.36 0.41 0.25
0.23 0.26 0.20 0.48 0.32 0.46 0.54
0.32 0.27 0.03 0.56 0.59 0.02 0.39
the violinists perceived a greater harmony and stillness, a freer breathing during sessions, and better concentration prior to performing. Some perceived that they could handle muscular tension in a better way and that they had an improved posture. Some also felt an awareness of interpreting signals from the body. The group suggested a longer training period than 8 weeks and more training sessions than once a week during intense rehearsal and performance periods since they experienced that the Basic BAT helped them to cope with intense work periods.
4. Discussion 4.1. The basic BAT intervention The present study found no significant changes in the EMG trapezius muscle activity pattern in the Basic BAT training group. However, the group experienced positive perceptions of breathing, muscular tension, postural control and concentration, mainly during practice sessions. The 8-week training period of Basic BAT might be long enough for the violinists to experience positive bodily perceptions but not long enough to change the EMG muscle activity pattern. The musicians would probably benefit from a longer training period, which also was suggested by the subjects in the Basic BAT training group in the evaluation of this intervention. Roxendal and Winberg (2002) have made comments concerning the length of the
Basic BAT training period of a clinical intervention in string musicians with chronic pain. They concluded that good results were achieved when practising individual Basic BAT during 3–8 months with 32 sessions as mean. The string musicians in that clinical intervention were chronic pain patients suffering from disorders up to 15 years and had been treated with other modalities before the Basic BAT, which was not the case in our study. The subjects in the present study were not diagnosed as pain patients and they were all working at the time for the intervention. Studies evaluating practice with various bodyoriented techniques among musicians have found positive changes in perceptions of muscle tension and movement pattern (Dommerholt et al., 1998; Brandfonbrener and Kjelland, 2002; Roxendal and Winberg, 2002). The results are mainly based on clinical assessments while very few studies have used EMG in the evaluation of muscle activity. Changes in EMG activity in the trapezius muscle after practising Basic BAT have been shown in a study on the effects of dynamic training programs for women with work-related trapezius myalgia (Ahlgren et al., 2001). The study indicated that women who practised co-ordination (Basic BAT) of the neck and shoulder muscles improved their ability to relax and to utilise pauses as compared with women who trained strength or endurance. Furthermore, the study had a rehabilitation scope and focused on pain and the EMG signal was analysed with respect to the signal–amplitude ratio, which was not the case in our study.
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4.2. Training interventions in musicians Time limitation was a reason for not attending the intervention in the present study. Although the training sessions were included in the work schedule, which was perceived as positive, it was added as ‘‘one more work task to do’’. This was also found by Brandfonbrener (1997) who studied the problems with implementing and maintaining a prevention program among orchestra musicians. A program with lectures on musculoskeletal education and specific exercises for the upper extremity was implemented in orchestra musicians with three visits over a 1-year period. The study had a very low attendance rate, almost 40% of the participants dropped out. The reasons for the withdrawals were due to time limitations and a feeling that the program was ‘‘just one thing too much’’. If management were to provide time for exercise the musicians would endorse the training. The dropouts also thought that even thinking about injuries was negative in itself, which might make them more vulnerable to disorders. 4.3. The work technique Concepts of motor learning and motor control (Shumway-Cook and Woollacott, 2001) and interventions over a shorter period suggests that the best time to prevent musicians’ disorders seems to be during the early stages of education (Brandfonbrener and Kjelland, 2002). Prevention from the earliest lessons implements efficient performance techniques, postural habits, a positive attitude and a healthy lifestyle. This highlights how important it is that music teachers instruct their students in proper playing technique at an early age and that teachers learn how to address postural and movement faults before they lead to injury (Medoff, 1999). Brandfonbrener (1998) questions whether it is a health benefit or a hazard to have played a musical instrument from early childhood starting before the body is full-grown. The partial answer lies in how the instrument and player interact, the technique, the player’s natural equipment and the quality of the teaching. Brandfonbrener (1998) emphasises that there is a potential for the music teacher to influence, good
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or bad, the musical life and development of a young musician. She further argues that there are many considerations in selecting a music teacher. Therefore, it should be a mutual process between the teacher, the music student and for the young student also the parents. Questions of the music teacher’s musical competence are vital, but questions of communication, teaching style and mutually compatible goals are equally important. Later on when the playing technique has been established, musicians might benefit more from practising proper warming up before playing, taking regular pauses to recover and a good working technique in activities other than playing an instrument (Spaulding, l988). These activities could also be practised in Basic BAT. A good work environment could further be improved by ergonomic work place factors such as comfortable chairs and adjustable music stands. Aspects of the total practice time and a good psychosocial work environment must also be considered. 4.4. Methodological considerations In this study, EMG measurements were made on the trapezius muscle bilaterally, based on the fact that the trapezius muscle is active in violin playing (Philipson et al., 1990; Berque and Gray, 2002), and it seems to be more vulnerable to muscle tension and pain than other neck and shoulder muscles (Vasseljen et al., 2001). A study design with EMG measurements of other muscles important to violin playing could have shown if there were differences in the muscle activity pattern of other shoulder muscles as well. Berque and Gray (2002) have proposed that violinists with a low amount of neck and shoulder pain may redistribute the load to other synergistic muscles. Their proposal is based on results by Palmerud et al. (1998), who showed that it is possible to reduce the muscle activity in the upper part of the trapezius muscle without changing the arm position or the hand load. On the other hand, reducing the trapezius muscle activity may increase the muscle activity in other shoulder muscles, mainly the rhomboid major and minor, the transverse part of the trapezius, the deltoideus and the serratus anterior.
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5. Conclusions Overall, this study found no differences in muscle activity between a group of violinists practising a body awareness technique and a non training group. Still, the Basic BAT-trained group perceived positive changes in breathing, muscular tension, postural control and concentration mainly during practise sessions. This emphasises the importance of music teachers instructing their students in a proper playing technique since it seems hard to influence once it has become established. Good postures and playing techniques have to be learned while playing the instrument but might also be emphasized in training modalities such as Basic BAT. However, a longer training period is probably necessary to affect the EMG muscle activity pattern. Practising proper warming up, taking regular pauses to recover and using good working techniques in activities other than playing the instrument are also important. Conclusions from this study must be drawn with care because of the relatively small sample sizes. Larger groups of string musicians need to be studied to allow for more accurate conclusions.
Acknowledgements The authors would like to thank Arbetsmarkna. akringsaktiebolag AFA, The Foundation dens fors. of Mutual Accident Insurance Company ‘‘Land . och Sjo’’, The Kempe foundation and The Swedish Association of Registered Physiotherapist for financial support. Thanks also to the phy. siotherapists Yvonne Bergstrom, Maria Bjurman and Virpi Jylh.a for valuable assistance in collecting the data and to Maria Wiklund for skilled guidance of the body awareness therapy.
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