Instrument playing as a system of sound production has received much attention in physical rehabilitation because it involves patterned physical movement. Instrument playing is highly effective as a therapeutic modality in rehabilitation because it induces repetitive physical movement in a predictable manner (Jeong, 2013). Drums are one of the easiest instruments to play because they involve simply striking the surface of the drum to make a sound. However, much of the research regarding instrument playing and muscle movement focuses on orchestra instruments and professional musicians. For example, researchers investigated muscle activation in the finger, wrist, and arm while playing string instruments (Guettler, 1992; Thiem et al., 1994) and keyboards (Lai et al., 2008; Oikawa et al., 2011; Penn et al., 1999). Findings from these studies confirmed the specific muscle groups that are involved in instrument playing by musicians who complete long-term music training. A positive relationship between forearm muscle activation and sound level for piano playing was revealed by surface electromyography (sEMG) data (Oikawa et al., 2011). With regards to different positions, the maximal voluntary contraction (MVC) was smallest at the neutral position, especially playing at a medium or strong sound level, indicating some degree of interaction between piano playing position and sound level.

With regard to EMG responses during percussive instrument playing, Fujii et al. (2009) examined wrist muscle activity underlying the stability of drumming. Participants with different music training backgrounds played the drum using dominant and nondominant hands separately to observe wrist flexion and extension at the flexor capri ulnaris and extensor carpi radialis. The results showed that the rate and evenness of inter-tap-interval in drumming increased with the level of drumming expertise. Further, cocontraction of EMG patterns between flexor capri ulnaris and extensor carpi radialis was found, indicating reciprocal wrist muscle activity underlying fast and stable drumming performance. Fujisawa and Miura (2010) examined how wrist muscle activity differed by music expertise, playing strategy, and drumstick size. Participants with various levels of drumming experience (i.e., nondrummer, novice drummer, amateur drummer, and trained drummer) played drums using drumsticks of varying weights and lengths. In general, the EMG activity measured at the flexor carpi ulnaris muscle of both arms was significantly less when participants engaged in free drum playing with a regular sized drumstick. The EMG activity was significantly greater with decreased length as well as with increased weight of the drumstick. Specific to the trained drummers, the amplitude of sEMG was evenly distributed over time, and the motor control pattern was consistent over both arms.

Most of this research focuses on the relationship between performance strategy and muscle activity with few studies exploring the perceptual properties of percussive sounds. One study investigated whether virtual and perceived sounds differed by the type of drum stroke, either normal or controlled (Dahl and Altenmuller, 2008). Various vectors (i.e., peak force, contact duration, and stick velocity) differed. Results showed that the participants produced a significantly higher peak force and shorter contact duration in the controlled stroke condition. Stick velocity, also associated with the controlled stroke, resulted in greater difference between pre- and postsurface impact. Sounds produced using controlled strokes were perceived as having a less full timbre and softer attack, indicating that different types of drum strokes induce significantly different levels of perception of drumming sounds. Another study analyzed sEMG signals associated with different instrument grasping patterns and varying tempo of hand percussion playing (Chong et al., 2015). When three different hand percussion instruments were compared, the small sphere type instrument elicited significantly greater muscle activation. In addition to the type of instrument, the results showed that tempo was also an important factor influencing degree of muscle activation. Although the above-mentioned studies provide detailed information regarding muscle movements in relation to playing techniques and methods, the interpretation of the results is limited to the specific musical strategies used in these studies. While muscle movements associated with classical music are well documented, those related to other music genres remain less understood.

Muscle activities measured by sEMG during drum playing have been widely studied from the trunk to the fingers; however, the information regarding muscle activation of the biceps brachii and triceps brachii during drum playing is still the blind spot for related academic areas, including rehabilitation and therapeutic use of instrument playing. Even though biceps brachii and triceps brachii are the main muscles in the upper arm, which would be activated by instrument playing for rehabilitation, little scientific evidence exists on their level of activity and relationship to sound intensity in drum playing. Thus, this study investigated sound intensity and muscle activation during drum playing.

In the present study, we measured the amplitude of sEMG during striking motion involving extension and flexion of the dominant upper arm. Regarding the use of a drumstick, muscle activation of the biceps brachii was larger for soft and medium drum playing with the drumstick while the triceps brachii showed smaller activation for all three stroke conditions when playing with the drumstick. This is because drum striking is made mainly by the downward movement of the forearm, which involves the action of elbow extension, generated by the triceps brachii. In this movement, the biceps brachii mainly acts on controlling speed and direction against the movement of the triceps brachii.

Regardless of drumstick use, similar sound intensity levels were demonstrated in each striking condition. This finding suggests that the drumstick is not necessarily required to control the produced sound; however, less vibrotactile feedback is transmitted to the hand when using a drumstick. As revealed in Chong et al. (2015), manipulating tempo during instrument playing has a greater impact than adjusting sound intensity level on increasing muscle activation. Also, the difference in sEMG of the triceps brachii between sound levels was larger than that of the biceps brachii. This observation coincides with results from Fujisawa and Miura (2010) who examined how wrist muscle activity differed by drumstick size. The authors found that EMG activity was significantly greater with decreased length and increased weight of the drumstick. For upper limb rehabilitation purposes, drum playing with a drumstick can be an effective option depending on the target muscle and the need for real-time vibrotactile feedback.

A possible use of the data from this study is in designing physical rehabilitation programs using drum playing. Alternating the produced sound level (dB) while playing a drum can be a practical intervention, and more effective therapeutic instrument playing can be provided if the required sound intensity level is controlled. It was generally believed that using drumsticks during drum playing involved more motor control since grabbing the drumstick was required; therefore, more muscle activation was expected. However, this study demonstrated via sEMG data that muscle activation is actually not associated with the use of drumsticks in drum playing. Thus, the use of drumsticks results in less movement being required and in a relatively reduced range of motion. The wider range of motion resulting from drum playing without drumsticks produces higher muscle activation making drum playing an ideal therapeutic treatment with the drum placed so that it addresses the upper limb targeted for rehabilitation.

In sum, the sound level should be loud enough to induce a certain level of muscle activation, and not using drumsticks is recommended when the therapist wants to focus on the triceps brachii muscle group. Also, hand drumming should be considered to increase muscle activation of the biceps brachii muscle group in the upper arms. Based on the results of this study, future research should investigate muscle activation and instrument playing in individuals with physical disabilities.