The impact of injury definitions on measures of injury occurrence in classical music students: a prospective cohort study

This prospective cohort study was performed among first-year classical music students at Codarts University of the Arts, Rotterdam, The Netherlands. All first year students following the Bachelor of Classical Music were invited to participate and the participation was offered as part of an educational program focusing on health-related subjects in classical music. All participants were informed about the procedure and provided informed consent. The study was approved by the Medical Ethics Committee (MEC-2019-0163) of the Erasmus MC University Medical Center Rotterdam, The Netherlands.

At the start of the academic year, all participating students were asked to complete an online intake questionnaire using the Performing artist and Athlete Health Monitor (PAHM) [19]. PAHM is a web-based system, developed to monitor physical and mental health in athletes, performing arts students and performing artists [19, 20]. The intake questionnaire included items on age, sex, body weight, height and previous injuries (injuries lasting at least one week in the previous year). In addition, all students were asked about their main subject (instrument), playing history (years of playing), their break behavior (minutes), warm-up (yes/no, with or without instrument) and estimated playing hours per week. During the academic year, bi-monthly questionnaires were sent to all participating students. These follow-up questionnaires included questions on the occurrence of any MSK complaints in the past eight weeks on a Visual Analogue Scale (VAS) (0–100; 0 – no pain; 100 – worst pain you can imagine) [9], time-loss (number of days partly/completely missed music activities due to a musculoskeletal problem), and contact with a health provider (yes/no). To establish the extent of the disability when playing a musical instrument, the Disabilities of the Arm, Shoulder and Hand performing arts module (DASH-pa) was used [21]. The DASH-pa is an optional module of the DASH that has shown good internal consistency and discriminative validity between music students with and without PRMD [22]. The DASH-pa consists of four items (DASH1, DASH2, DASH3, DASH4), with scores from 0 (not disabled) to 100 (most severe disability), which together form a DASH-pa sum score using a specific calculation. Non-responders received two reminder e-mails within a week and were also reminded about the questionnaire in person during classes.

In agreement with the literature by Clarsen and Bahr on sports injury definitions [16], we used the three sports injury definitions and slightly modified these to better fit our specific target population (i.e. classical music students):

- all MSK complaints injury: any MSK complaint resulting in a VAS pain score > 0 in the past eight weeks.

- medical attention injury: any MSK complaint that resulted in a student consulting a health provider in the past eight weeks.

-time-loss injury: any MSK complaint that resulted in partly/completely missing music classes or activities in the past eight weeks.

Statistical analyses were conducted using SPSS version 24. Baseline characteristics were calculated with descriptive statistics using means and standard deviations (SD) or numbers and percentages (%). Prevalences for one academic year were calculated by dividing the number of students that reported at least one injury (according to the three injury definitions) during the academic year by the number of respondents in that same period [23]. Confidence intervals (CI) for all three definitions were compared.

Prevalences for a two-month time period were calculated by dividing the number of students that reported at least one injury (according to the three injury definitions) during those two months by the number of respondents in that same period [23].

For the Visual Analogue Scale, the bi-monthly mean scores and ranges were included. Categories were used to establish a mild (≤ 30), moderate (31–69) or severe (≥ 70) level of MSK complaints [24].

Following the scoring instructions by the Institute for Work & Health [25], the DASH-pa sum scores were established by using the following calculation: ((((DASH1 + DASH2 + DASH3 + DASH4) / 4) - 1) * 25). The scores were calculated for the three injury definitions separately by using the sum scores of all students who indicated one of the three injury definitions. So for example: the average of all DASH-pa sum scores of all students seeking medical treatment formed the DASH-pa score for medical attention.

In total, 28 out of 29 students reported at least one MSK complaint (VAS > 0) during the academic year, resulting in a one year prevalence of 96.6% (95% CI: 0.899, 1.032). The bi-monthly prevalences ranged from 74.1 to 96.0% (Fig. 1). The average scores on the VAS ranged from 15.63 to 29.83 (Table 2). In all periods (November until May) most students reported mild MSK complaints, ranging from 50 to 85.2%. Bi-monthly DASH-pa scores for all students reporting a MSK complaint ranged from 15.6 to 26.9 (Fig. 2).

In total, five out of 29 students visited a health provider throughout the academic year, resulting in a one-year prevalence of medical attention injuries of 17.2% (95% CI: 0.035, 0.31). The students’ main subjects were double bass (n = 2), violin, trombone and vocals (Table 3). The bi-monthly prevalences for medical attention ranged from 7.4 to 12.0%. (Fig. 1). The five students indicated that they had visited a physiotherapist or speech therapist (six physio treatments, three speech therapist treatments and one treatment by both physio and speech therapist) during one year. DASH-pa scores for all students reporting a medical attention injury ranged from 33.3–50 (Fig. 2).

In total, four out of 29 students reported to have partly/completely missed music activities for at least a day due to a MSK complaint during one academic year, resulting in a prevalence of 13.8% (95% CI: 0.012, 0.263). The students’ main subjects were double bass (n = 3) and bass trombone (Table 3). The bi-monthly prevalences of time-loss injuries ranged from 0 to 11.5% (Fig. 1). The average number of days missed because of a MSK complaint was 2.6 (SD 1.8). Two students who reported a time-loss injury received medical care at the same time. Both those students played double bass. DASH-pa scores for all students reporting a time-loss injury ranged from 47.9 to 62.5 (Fig. 2).

Figure 3 shows the distribution and overlap of the three different injury definitions over one academic year. The figure represents all students with a MSK complaint, n = 28 (100%), in the previous year and shows which of those complaints resulted in a medical attention injury, n = 3 (10.7%), time-loss injury, n = 2 (7.1%) or both a medical attention and time-loss injury, n = 2 (7.1%).

Bahr and Clarsen proposed a model that represents interactions between various injury definitions for sports [16]. It is assumed that all time-loss injuries are medical attention injuries as well, indicating that athletes visit a health provider when time-loss injuries occur. It is also assumed that all medical attention injuries are part of the total injury burden, measured with the ‘all complaints’ definition. In our study focusing on classical music students, this specific model does not seem fully applicable. Figure 3 shows that not all students reporting a time-loss injury also indicate a medical attention injury. This could be explained by the cultural norm in the performing arts as noted before [17, 18]. More insight into the culture of the performing arts can provide practical implications for prevention. Qualitative studies can provide insight into the underlying causes of the cultural norm. Concerning the changes in the interaction model for a population of musicians, prospective studies with a larger population should be conducted to confirm these.

This is the first study investigating the influence of the three injury definitions proposed by Clarsen et al. [16] on prevalences in a group of classical music students. A strength of our prospective cohort study is the response rate of 85%, which is considered high in this population. One of the advantages of the current study is that filling in the bi-monthly questionnaire was part of an educational program within the curriculum. This stimulated the participants to fill in the questionnaire. Also, this is one of the first studies using a prospective cohort design which gives us the possibility to monitor music students’ complaints over a longer period of time. Furthermore, the DASH-pa module used in the current study, was previously examined by Baadjou and colleagues (2017) and showed good discriminative validity, good internal consistency and moderate construct validity in a population of music students [22].

However, there are some limitations. First of all, the sample size in the current study is small which makes it difficult to draw firm conclusions. Future research should include a larger sample size in order to overcome this issue. The few students who suffered from a time-loss injury all played a large instrument. We suggest to elaborate more on this in future research, using a larger sample to see whether students playing larger instruments actually suffer more from time-loss injuries.

Secondly, we did not explicitly ask about the occurrence of Playing-Related Musculoskeletal Disorders (PRMD) and were therefore not able to calculate the prevalence of this type of injury. The original definition developed by Zaza and colleagues (1998) is: ‘pain, weakness, numbness, tingling or other symptoms that interfere with (their) ability to play (their) instrument at the level (they) are accustomed to’ [11]. Using PRMD as an injury definition can be interesting especially for musicians, conservatoires and music healthcare specialists, in order to focus on prevention within the specific environment of musicians. Additionally, information about the location of PRMD might be useful to develop prevention programs focusing on different instrument groups.

Moreover, we used a period of eight weeks to monitor the students. While monitoring on a monthly basis provides more information and decreases recall bias, due to scheduling limitations it was not possible to implement a monthly questionnaire in the curriculum structure.