Biomechanical Basis of Interval Throwing Programs for Baseball Pitchers: A Systematic Review

# Background Interval throwing programs are used in rehabilitation of throwing injuries, especially ulnar collateral ligament injuries. Athletes who are rehabilitating begin by throwing on flat ground progressing through increasing distances, number of throws, and intensity of throwing. If the athl...

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Main Authors: Travis Dias, Benjamin G. Lerch, Jonathan S. Slowik, Kevin E. Wilk, James R. Andrews, E. Lyle Cain, Glenn S. Fleisig
Format: Article
Language:English
Published: North American Sports Medicine Institute 2023-10-01
Series:International Journal of Sports Physical Therapy
Online Access:https://doi.org/10.26603/001c.87811
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author Travis Dias
Benjamin G. Lerch
Jonathan S. Slowik
Kevin E. Wilk
James R. Andrews
E. Lyle Cain
Glenn S. Fleisig
author_facet Travis Dias
Benjamin G. Lerch
Jonathan S. Slowik
Kevin E. Wilk
James R. Andrews
E. Lyle Cain
Glenn S. Fleisig
author_sort Travis Dias
collection DOAJ
description # Background Interval throwing programs are used in rehabilitation of throwing injuries, especially ulnar collateral ligament injuries. Athletes who are rehabilitating begin by throwing on flat ground progressing through increasing distances, number of throws, and intensity of throwing. If the athlete is a baseball pitcher, the flat-ground throwing phase is followed by pitching on a mound at progressively increased effort. The goal is to build back arm strength and capacity with an emphasis on proper mechanics. # Purpose To determine whether interval throwing progressively builds joint kinetics (specifically, elbow varus torque) to the level required during full-effort baseball pitching. A secondary purpose was to examine the kinematics produced during interval throwing compared to those seen during baseball pitching. # Study Design Systematic Review # Methods Following PRISMA guidelines, PubMed, Embase, Web of Science, SPORTDiscus, and Google Scholar were systematically searched for biomechanical studies of flat-ground throwing and partial-effort pitching in baseball between 1987 and 2023. Studies that reported the biomechanics of either flat-ground throwing, or partial-effort pitching were included in this review. The AXIS tool was used to assess study quality. # Results Thirteen articles met the inclusion criteria. Ten studies were determined to be of moderate quality, while three studies were deemed high quality. Elbow varus torque during partial-effort pitching was less than during full-effort pitching. Elbow varus torque for most flat-ground throws did not exceed full-effort pitching torque. While most studies showed increased elbow varus torque with increased flat-ground throwing distance, the distance at which elbow varus torque matched or exceeded full-effort pitching elbow varus torque was not consistent. As flat-ground throwing distance increased, shoulder external rotation angle and shoulder internal rotation velocity increased. Arm slot (forearm angle above horizontal) decreased as flat-ground throwing distance increased. For varied effort pitching, shoulder external rotation angle, shoulder internal rotation velocity, elbow extension velocity, and ball velocity increased as effort increased. While the front knee extended slightly from foot contact to ball release in full-effort pitching, the front knee flexed slightly during partial-effort pitching. # Conclusions An interval throwing program progressively builds elbow varus torque up to levels produced in full-effort baseball pitching. While differences exist between interval throwing kinematics and pitching kinematics, the patterns are similar in general. # Level of Evidence 2
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spelling doaj-art-165ccbe1488048e5a606781b9a6856772025-02-11T20:27:12ZengNorth American Sports Medicine InstituteInternational Journal of Sports Physical Therapy2159-28962023-10-01185Biomechanical Basis of Interval Throwing Programs for Baseball Pitchers: A Systematic ReviewTravis DiasBenjamin G. LerchJonathan S. SlowikKevin E. WilkJames R. AndrewsE. Lyle CainGlenn S. Fleisig# Background Interval throwing programs are used in rehabilitation of throwing injuries, especially ulnar collateral ligament injuries. Athletes who are rehabilitating begin by throwing on flat ground progressing through increasing distances, number of throws, and intensity of throwing. If the athlete is a baseball pitcher, the flat-ground throwing phase is followed by pitching on a mound at progressively increased effort. The goal is to build back arm strength and capacity with an emphasis on proper mechanics. # Purpose To determine whether interval throwing progressively builds joint kinetics (specifically, elbow varus torque) to the level required during full-effort baseball pitching. A secondary purpose was to examine the kinematics produced during interval throwing compared to those seen during baseball pitching. # Study Design Systematic Review # Methods Following PRISMA guidelines, PubMed, Embase, Web of Science, SPORTDiscus, and Google Scholar were systematically searched for biomechanical studies of flat-ground throwing and partial-effort pitching in baseball between 1987 and 2023. Studies that reported the biomechanics of either flat-ground throwing, or partial-effort pitching were included in this review. The AXIS tool was used to assess study quality. # Results Thirteen articles met the inclusion criteria. Ten studies were determined to be of moderate quality, while three studies were deemed high quality. Elbow varus torque during partial-effort pitching was less than during full-effort pitching. Elbow varus torque for most flat-ground throws did not exceed full-effort pitching torque. While most studies showed increased elbow varus torque with increased flat-ground throwing distance, the distance at which elbow varus torque matched or exceeded full-effort pitching elbow varus torque was not consistent. As flat-ground throwing distance increased, shoulder external rotation angle and shoulder internal rotation velocity increased. Arm slot (forearm angle above horizontal) decreased as flat-ground throwing distance increased. For varied effort pitching, shoulder external rotation angle, shoulder internal rotation velocity, elbow extension velocity, and ball velocity increased as effort increased. While the front knee extended slightly from foot contact to ball release in full-effort pitching, the front knee flexed slightly during partial-effort pitching. # Conclusions An interval throwing program progressively builds elbow varus torque up to levels produced in full-effort baseball pitching. While differences exist between interval throwing kinematics and pitching kinematics, the patterns are similar in general. # Level of Evidence 2https://doi.org/10.26603/001c.87811
spellingShingle Travis Dias
Benjamin G. Lerch
Jonathan S. Slowik
Kevin E. Wilk
James R. Andrews
E. Lyle Cain
Glenn S. Fleisig
Biomechanical Basis of Interval Throwing Programs for Baseball Pitchers: A Systematic Review
International Journal of Sports Physical Therapy
title Biomechanical Basis of Interval Throwing Programs for Baseball Pitchers: A Systematic Review
title_full Biomechanical Basis of Interval Throwing Programs for Baseball Pitchers: A Systematic Review
title_fullStr Biomechanical Basis of Interval Throwing Programs for Baseball Pitchers: A Systematic Review
title_full_unstemmed Biomechanical Basis of Interval Throwing Programs for Baseball Pitchers: A Systematic Review
title_short Biomechanical Basis of Interval Throwing Programs for Baseball Pitchers: A Systematic Review
title_sort biomechanical basis of interval throwing programs for baseball pitchers a systematic review
url https://doi.org/10.26603/001c.87811
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