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Baseball has become increasingly popular in recent years, with 25 million participants reported in 2017 (Sport & Fitness Industry Association, 2017). As baseball’s popularity increases, more researchers are examining the critical aspects of the game such as the kinetic forces placed on the shoulder, the repetitive loading forces generated by the shoulder muscles and injuries related to baseball that result from these forces. One of the most integral parts of the sport is the overhead throw, which is an intricate and highly coordinated musculoskeletal sequence (Chalmers et al., 2017). Due to the complexity of this movement, baseball players are often at a greater risk of injury. As such, baseball has been estimated to account for greater than 50,000 injuries per year (Cools et al., 2002). The significant and repetitive microtrauma placed on the shoulder during an overhead throw can cause maladaptive changes to the soft tissue or even bony structures surrounding the shoulder (Erickson et al., 2016b). Pitching related shoulder and elbow pain is reported in 46-57% of pitchers (Lyman et al., 2001).
An overhead throw is comprised of six distinct phases including the wind-up phase, early cocking phase, late cocking phase, acceleration phase, deceleration phase, and follow through phase (Fleisig et al., 1995). During these phases, a few muscles play a key role in the motions that make up an overhead throw and include the pectoralis major, infraspinatus, and the supraspinatus muscles (Erickson et al., 2016). The pectoralis major muscle reaches peak activation during the late cocking phase of the overhead throw, as it is eccentrically loaded and contracts to control the force and decelerate the velocity generated by the shoulder external rotators (Erickson et al., 2016). The infraspinatus and supraspinatus muscles reach peak activation in the late cocking phase of the overhead throw (Erickson et al., 2016). The supraspinatus muscle is the most commonly torn rotator cuff muscle and is at high risk of injury during this phase (Braun et al, 2009; Erickson et al., 2016b).
Many researchers have used EMG in order to examine the effects of Kinesio Tape® on muscle recruitment during different functional and sport specific tasks (Hsu et al., 2009; Janwantanakul & Gaogasigam, 2005; Reynard et al., 2018; Slupik et al., 2007; Vithoulk et al., n.d.; Zanca et al., 2016). Hsu et al. (2009) investigated the effects of Kinesio Tape® on scapular kinematics, muscle strength, and EMG activity in baseball players with shoulder impingement problems. In this pilot study, they applied Kinesio Tape® to the lower fibres of the trapezius muscle and looked at scaption (Hsu et al., 2009). Scaption is defined as the elevation of the humerus in the scapular plane (30 degrees anterior to the frontal plane) and participants were asked to move in this plane paced to a metronome guided by a wooden pole (Hsu et al., 2009). Once participants were coordinated to the pace of the metronome, they were given a 2 kg weight and asked to perform three repetitions of this motion with the weight in their hand while EMG data was collected from the lower trapezius and serratus anterior muscles. Hsu et al. (2009) reported that with the application of Kinesio Tape® to the lower fibres of the trapezius muscle, there was increased muscle activity during 60-30 degrees of the lowering phase of the scaption movement. There was also increased scapula posterior tilt at 30 and 60 degrees positions of arm scaption.
Zhang et al. (2016) examined the immediate effect of Kinesio Tape® applied over the wrist extensor and flexor muscles on muscle strength and endurance during isometric and isokinetic muscle testing at both low (60 degrees per second) and high (210 degrees per second) angular speeds (Zhang et al., 2016). Participants completed the tasks under three different taping conditions including no tape, placebo tape, and Kinesio Tape® (Zhang et al., 2016). Isometric maximal voluntary contractions and isokinetic wrist extension and flexion forces were measured using a dynamometer (Zhang et al., 2016). The application of Kinesio Tape® resulted in no change in normalized peak moment, peak power, average power, and total work in the wrist flexor and extensor muscles (Zhang et al., 2016). The application of Kinesio Tape® applied to the wrist flexors; however, resulted in reduced work fatigue and resulted in a lower rate of decline in moment compared to the no taping condition (Zhang et al., 2016). This suggests that Kinesio Tape® may have a positive effect on muscle fatigue resistance during repeated concentric muscle actions (Zhang et al., 2016).