Effects of Mound Versus Flat-Ground Pitching and Distance on Arm Mechanics and Elbow Torque in High School Pitchers

Abstract

Background: Although the monitoring of a pitcher’s throwing arm workload has become a hot topic in both research and the pitching world, the impact of mound height and distance still remains unclear. Purpose: To compare the kinetics and kinematics between pitches from a mound and flat ground at 2 different distances. Study Design: Descriptive laboratory study. Methods: A total of 21 healthy high school varsity baseball pitchers (age, 16.2 ± 1.3 years; weight, 73.6 ± 11.0 kg; height, 181.3 ± 6.4 cm) participated in this study. Players were fitted with a motusBASEBALL sensor and sleeve. Each pitcher was instructed to pitch 5 fastballs under 4 conditions: mound at 60.5 ft (regulation distance), flat ground at 60.5 ft, mound at 50.5 ft, and flat ground at 50.5 ft. Linear mixed-effects models were used to account for both intra- and interplayer variability. A multivariable model was used to evaluate the association of mound pitching, flat-ground pitching, and their distances (50.5 ft and 60.5 ft), and their interaction to arm speed, arm slot, arm rotation, elbow varus torque, and ball velocity. Results: There were no statistically significant effects of mound, flat-ground, or distance variation on arm speed or shoulder rotation. Arm slot was significantly higher (+3.0°; P = .02) on pitches from the mound at 60.5 ft compared with 50.5 ft. Elbow varus torque was lower (–1.5 N·m; P = .02) on mound pitches at 60.5 ft compared with 50.5 ft. Pitches thrown from the mound displayed significantly faster ball velocity compared with flat-ground pitches at both distances ( P < .01 for both), with pitches at 60.5 ft having higher velocity (+0.7 m/s; P < .01). Conclusion: Contrary to long-standing notions, the study results suggest that pitching from the mound does not significantly increase stress on the elbow compared with flat-ground pitching. Lower elbow varus torque and faster ball velocity at the regulation distance compared with the reduced distance indicate that elbow stress and ball velocity may not correlate perfectly, and radar guns may not be an appropriate surrogate measure of elbow varus torque. Clinical Relevance: A better understanding of the kinetic and kinematic implications of various throwing programs will allow for the designing of programs that are driven by objective data with aims directed toward injury prevention and rehabilitation in baseball pitchers.

The Effect of the Crow Hop on Elbow Stress During an Interval Throwing Program: Letter to the Editor

“…We would like to thank the Journal for the opportunity to respond to the Letter to the Editor by Wong et al regarding our recently published study entitled ''The Effect of the Crow Hop on Elbow Stress During an Interval Throwing Program.'' 5 We appreciate the recognition of effort by the letter authors regarding our study and the importance of conducting such studies on overhead athletes. Below, we outline our response to their concerns.…”

“…1,7 Unfortunately, other researchers have erroneously utilized the Motus sleeve to also draw conclusions on interval throwing programs. 3,5,6,12,[14][15][16][17][18][19] The first study by Camp et al 3 in 2017, which coincidentally was not intended to be a validation study, briefly described how the device was validated, and other researchers 5,6,[12][13][14][15][16][17][18][19] then proceeded to cite this index study as an indication that the Motus sleeve is a validated tool when developing their methods. Driggers et al 7 expressed their concerns regarding the Camp et al 3 index study, in which they brought to light how the Motus sensor was not adequately validated.…”

“…We advise the medical community to critically reconsider the conclusions and statements coming out of all the published papers investigating components related to an interval throwing program utilizing this invalidated IMU device. 3,5,6,[12][13][14][15][16][17][18][19] If a sound methodological design is incorporated, we can have greater confidence in the results and draw more applicable conclusions and statements to best help recovering baseball athletes with the safest healing environment when progressing through an interval throwing program.…”

Increased Shoulder Distraction Force and Shoulder Horizontal Abduction in Professional Baseball Pitchers With Discordant Torso Rotation Order

“…7,19 Pitch efficiency was calculated as the ratio between ball velocity and elbow varus torque. This metric was calculated to estimate the degree of torque on the joint relative to the amount of velocity produced, as conducted by Dowling et al 8 Pitches were considered to entail discordant torso rotation sequences when peak pelvic rotation velocity occurred after peak upper torso rotation velocity by more than the standard error of measurement (SEM) of the peak upper torso rotation velocity, defined by Oyama et al 25 as 3.7% of pitch time. The SEM of peak upper torso rotation velocity was used as a cutoff criterion because it was larger than the SEM of the timing of peak pelvic rotation velocity.…”

Are Wearable Sensors Valid and Reliable for Studying the Baseball Pitching Motion? An Independent Comparison With Marker-Based Motion Capture

“…Recently, inertial measurement unit (IMU) technology has allowed for the evaluation of throwing kinematics and kinetics outside of the traditional laboratory setting. 6,9,12,30 Thus far, the motusBASEBALL (Motus Global) IMU has been used to evaluate intrathrower and interthrower variabilities during structured long-toss programs 18,25 and pitching with different efforts, 21 providing valuable information to help structure rehabilitation and interval throwing programs. It has also been used to evaluate the effect of fatigue on the elbow during simulated games 28 and variations in kinematics across different pitch types.…”