Change in Pitching Biomechanics in the Late-Inning in Taiwanese High School Baseball Pitchers

Abstract

Repetitive overhead throwing may result in overuse injuries and a change in the pitching mechanics of a baseball pitcher. Accordingly, the purpose of this study is to quantify the changes in the muscle strength and pitching motion kinematics in the late-innings stage of a baseball game. Sixteen healthy baseball pitchers (16.77 ± 0.73 years) recruited from a high school, which won the National High School Baseball Championship in Taiwan in 2011; each performed 100 pitches in a bullpen throwing session. Isometric muscle strength measurements and joint kinematic data were obtained before and after the throwing session. The mean Borg's Rating of Perceived Exertion index was found to have a value of 14.14, indicating a medium-to-large degree of perceived tiredness. The results showed that the ball velocity and horizontal abduction angle decreased significantly as the pitchers became tired. Moreover, the upper torso forward tilt and knee flexion angle both increased significantly at the moment of ball release. Finally, the muscle strength of the upper extremity remained decreased 2 days after the bullpen throwing session. Overall, the results suggest that an adequate amount of rest and specific strengthening programs for the shoulder external rotator, shoulder internal rotator, shoulder flexor, shoulder extensor, shoulder adductor, and shoulder abductor muscles are recommended to the coaches and for adolescent baseball pitchers. In addition, the changes in pitching mechanics noted in this study should be carefully monitored during the course of a baseball game to minimize the risk for overuse injuries.

Manifestations of muscle fatigue in baseball pitchers: a systematic review

“…The majority of the included studies assessed athletes at the junior (Freeston et al, 2014; Lyman et al, 2001, 2002; Makhni et al, 2014; Oliver, Weimar & Henning, 2016; Yang et al, 2014), high school (Chou et al, 2015; Crotin et al, 2014; Erickson et al, 2016; Oliver & Plummer, 2010; Yang et al, 2014, 2016), or collegiate level (Crotin et al, 2014; Dale et al, 2007; Escamilla et al, 2007; Grantham et al, 2014; Keeley, Barber & Oliver, 2010; Mullaney et al, 2005; Tripp, Yochem & Uhl, 2007; Wang et al, 2016; Warren, Szymanski & Landers, 2015) with reported mean age ranges from 8 to 23 years old. Five of the 25 studies included professional baseball players (Bradbury & Forman, 2012; Crotin et al, 2013; Mullaney et al, 2005; Murray et al, 2001; Sonne & Keir, 2016; Whiteside et al, 2016), but an age range was only reported from one.…”

Effect of Glenohumeral Internal Rotation Deficit on Shoulder in Baseball Pitchers during Fastball Pitching

“…On completion of the pitching trials, the fastest 5 of the 15 strike pitches thrown by each pitcher were taken for data analysis purposes. Moreover, if ball speed was below 10% of the first five ball speed and pitcher's Borg's Rating of Perceived Exertion Scale (RPE, 4-20) [2] was above 11, the pitcher was regarded as tired.…”

“…Baseball pitching involves an extremely large range of motion (ROM) and very high angular velocities in the pitching cycle. The pitching motion was divided into six phases [1,2]; namely windup (i.e., from the beginning of motion until a balanced position); stride (i.e., from a balanced position until lead foot contact (FC)); arm cocking (i.e., from lead FC to the instant of maximum shoulder external rotation (MER)); arm acceleration (i.e., from the instant of MER to the instant of ball release (BR)); arm deceleration (i.e., from the instant of BR until the point of maximum shoulder internal rotation); and follow-through (i.e., from the point of maximum shoulder internal rotation until the end of motion). Previous studies have suggested that when pitching fastball, the shoulder external rotation could reach 170 degrees, and suffer shoulder external rotation torque as high as 70 Nm at the instant of maximal external rotation.…”

Peer Review #2 of "Manifestations of muscle fatigue in baseball pitchers: a systematic review (v0.2)"

“…The majority of the included studies assessed athletes at the junior (Freeston, et al, 2014;Lyman, et al, 2001;Lyman, et al, 2002;Makhni, et al, 2014;Oliver, Weimar & Henning, 2016;Yang, et al, 2014), high school (Chou, et al, 2015;Crotin, et al, 2016;Erickson, et al, 2016;Oliver & Plummer, 2010;Yang, et al, 2014;Yang, et al, 2016 ), or collegiate level (Crotin, et al, 2016;Dale, et al, 2007;Escamilla, et al, 2007;Grantham, et al, 2014;Keeley, Barber & Oliver, 2010;Mullaney, et al, 2005;Tripp, Yochem & Uhl, 2007;Wang, et al, 2016;Warren, Szymanski & Landers, 2015) with reported mean age ranges from 8 to 23 years old. Five of the 25 studies included professional baseball players (Bradbury & Forman, 2012;Crotin, et al, 2013;Mullaney, et al, 2005;Murray, et al, 2001;Sonne & Keir, 2016;Whiteside, et al, 2016), but an age range was only reported from one.…”

“…Manuscript to be reviewed included analysis of pitching records in minor league pitchers (Crotin et al, 2013) and publicly available data on professional pitchers (Sonne & Keir, 2016). Descriptive/controlled laboratory studies analyzed kinematic changes in a pitcher's delivery with the accumulation of fatigue (Chou, et al, 2015;Dale, et al, 2007;Erickson, et al, 2016;Escamilla, et al, 2007;Grantham, et al, 2014;Keeley, et al, 2017;Mullaney, et al, 2005;Murray, et al, 2001;Oliver & Plummer, 2010;Oliver, Weimar & Henning, 2016;Tripp, Yochem & Uhl, 2007;Wang, et al, 2016;Warren, Szymanski & Landers, 2015;Whiteside, et al, 2016). Randomized crossover studies (Crotin, et al, 2014;Yang et al, 2016;Freeston, et al, 2014) included comparing the effects of throwing exercises and identifying markers for arm fatigue (Freeston, et al, 2014), kinematic analysis while altering stride length over multiple sessions (Crotin et al, 2014) and examining the effects of rest intervals during a simulated game (Yang et al, 2016).…”