Establishing the Role of Elbow Muscles by Evaluating Muscle Activation and Co-contraction Levels at Maximal External Rotation in Fastball Pitching

Bart van Trigt*, Eva Galjee, Marco J.M. Hoozemans, Frans C.T. van der Helm, Dirk Jan H.E.J. Veeger

*Corresponding author for this work

Research output: Contribution to JournalArticleAcademicpeer-review

Abstract

Background: Baseball pitching is associated with a high prevalence of ulnar collateral ligament injuries, potentially due to the high external valgus load on the medial side of the elbow at the instant of maximal shoulder external rotation (MER). In-vitro studies show that external valgus torque is resisted by the ulnar collateral ligament but could also be compensated by elbow muscles. As the potential active contribution of these muscles in counteracting external valgus load during baseball pitching is unknown, the aim of this study is to determine whether and to what extent the elbow muscles are active at and around MER during a fastball pitch in baseball. Methods: Eleven uninjured pitchers threw 15 fastball pitches. Surface electromyography of six muscles crossing the elbow were measured at 2000 Hz. Electromyography signals were normalized to maximal activity values. Co-contraction index (CCI) was calculated between two pairs of the flexor and extensor elbow muscles. Confidence intervals were calculated at the instant of MER. Four ranges of muscle activity were considered; 0–20% was considered low; 21–40% moderate; 41–60% high and over 60% as very high. To determine MER, the pitching motion was captured with a highspeed camera at 240 Hz. Results: The flexor pronator mass, pronator teres, triceps brachii, biceps brachii, extensor supinator mass and anconeus show moderate activity at MER. Considerable variation between participants was found in all muscles. The CCI revealed co-contraction of the two flexor-extensor muscle pairs at MER. Interpretation: The muscle activation of the flexor and pronator muscles at MER indicates a direct contribution of forearm muscles crossing the medial side of the elbow in counteracting the external valgus load during fastball pitching. The activation of both flexor and extensor muscles indicates an in-direct contributory effect as the combined activity of these muscles counteract opening of the humeroulnar joint space. We believe that active muscular contributions counteracting the elbow valgus torque can be presumed to relieve the ulnar collateral ligament from maximal stress and are thus of importance in injury risk assessment in fastball pitching in baseball.

Original languageEnglish
Article number698592
Pages (from-to)1-9
Number of pages9
JournalFrontiers in Sports and Active Living
Volume3
Issue numberNovember
Early online date30 Nov 2021
DOIs
Publication statusPublished - Nov 2021

Bibliographical note

Funding Information:
This work was supported by the NWO Domain Applied and Engineering Sciences (AES) under project number [R/003635]. This NWO-funded project, named Breaking the High Load?Bad Coordination Multiplier in Overhead Sports Injuries part of the Citius Altius Sanius perspective program (Project 7), is a cooperative effort between the Royal Dutch Baseball and Softball Federation (KNBSB), Royal Dutch Tennis Federation (KNLTB), Vrije Universiteit Amsterdam, Delft University of Technology, Mil? Fysiotherapy, PitchPerfect, and PLUX.

Funding Information:
This work was supported by the NWO Domain Applied and Engineering Sciences (AES) under project number [R/003635]. This NWO-funded project, named Breaking the High Load—Bad Coordination Multiplier in Overhead Sports Injuries part of the Citius Altius Sanius perspective program (Project 7), is a cooperative effort between the Royal Dutch Baseball and Softball Federation (KNBSB), Royal Dutch Tennis Federation (KNLTB), Vrije Universiteit Amsterdam, Delft University of Technology, Milé Fysiotherapy, PitchPerfect, and PLUX.

Publisher Copyright:
Copyright © 2021 van Trigt, Galjee, Hoozemans, van der Helm and Veeger.

Funding

This work was supported by the NWO Domain Applied and Engineering Sciences (AES) under project number [R/003635]. This NWO-funded project, named Breaking the High Load?Bad Coordination Multiplier in Overhead Sports Injuries part of the Citius Altius Sanius perspective program (Project 7), is a cooperative effort between the Royal Dutch Baseball and Softball Federation (KNBSB), Royal Dutch Tennis Federation (KNLTB), Vrije Universiteit Amsterdam, Delft University of Technology, Mil? Fysiotherapy, PitchPerfect, and PLUX. This work was supported by the NWO Domain Applied and Engineering Sciences (AES) under project number [R/003635]. This NWO-funded project, named Breaking the High Load—Bad Coordination Multiplier in Overhead Sports Injuries part of the Citius Altius Sanius perspective program (Project 7), is a cooperative effort between the Royal Dutch Baseball and Softball Federation (KNBSB), Royal Dutch Tennis Federation (KNLTB), Vrije Universiteit Amsterdam, Delft University of Technology, Milé Fysiotherapy, PitchPerfect, and PLUX.

FundersFunder number
Citius Altius Sanius
KNBSB
KNLTB
NWO domain Applied and Engineering Sciences
Royal Dutch Baseball and Softball Federation
Royal Dutch Tennis Federation
AES CorporationR/003635
AES Corporation

    Keywords

    • baseball
    • electromyography
    • injury prevention
    • musculoskeletal injuries
    • overhead sports
    • Tommy John surgery
    • ulnar collateral ligament (UCL)

    Fingerprint

    Dive into the research topics of 'Establishing the Role of Elbow Muscles by Evaluating Muscle Activation and Co-contraction Levels at Maximal External Rotation in Fastball Pitching'. Together they form a unique fingerprint.

    Cite this