Youth Pitcher Fatigue: Medial Elbow Laxity, Ultrasonographic Assessment of Flexor-Pronator Mass Energy Depletion, and Association With Pitch Count.

Autor:	Schubert MF; Department of Orthopaedic Surgery, University of Michigan, Ann Arbor, Michigan, USA.; Department of Orthopaedic Surgery, Detroit Medical Center, Detroit, Michigan, USA., Awan TM; Department of Orthopaedic Surgery, University of Michigan, Ann Arbor, Michigan, USA.; Ascension Medical Group Beacon Orthopaedics of Michigan, Novi, Michigan, USA., Sciascia AD; Institute for Clinical Outcomes and Research, Lexington Clinic, Lexington, Kentucky, USA., Figueroa EG; Department of Orthopaedic Surgery, University of Michigan, Ann Arbor, Michigan, USA., DeMink JM; Department of Orthopaedic Surgery, University of Michigan, Ann Arbor, Michigan, USA., Selak DM; Department of Orthopaedic Surgery, University of Michigan, Ann Arbor, Michigan, USA., Snyder CM; Department of Orthopaedic Surgery, University of Michigan, Ann Arbor, Michigan, USA., Gagnier JJ; Department of Orthopaedic Surgery, University of Michigan, Ann Arbor, Michigan, USA.; Department of Epidemiology, School of Public Health, University of Michigan, Ann Arbor, Michigan, USA.; Department of Epidemiology and Biostatistics, Western University, London, Ontario, Canada., Freehill MT; Department of Orthopaedic Surgery, University of Michigan, Ann Arbor, Michigan, USA.; Department of Orthopaedic Surgery, Stanford University School of Medicine, Redwood City, California, USA.
Jazyk:	angličtina
Zdroj:	Orthopaedic journal of sports medicine [Orthop J Sports Med] 2024 Jun 18; Vol. 12 (6), pp. 23259671241256294. Date of Electronic Publication: 2024 Jun 18 (Print Publication: 2024).
DOI:	10.1177/23259671241256294
Abstrakt:	Background: Ulnar collateral ligament (UCL) injuries in youth pitchers continue to be concerning despite the institution of pitch count limits. Flexor-pronator mass fatigue can lead to diminished dynamic stability, resulting in greater stress on the UCL. Purpose/hypothesis: To evaluate fatigue of the flexor-pronator mass by assessing changes in medial elbow laxity; noninvasively characterizing alterations in muscle glycogen; and identifying changes in subjective fatigue, strength, range of motion (ROM), pitching velocity, and accuracy with increasing pitches thrown by youth pitchers to their recommended 75-pitch count limit. It was hypothesized that, with increased pitches, medial elbow laxity would increase and that the glycogen content of the flexor-pronator mass would decrease. Study Design: Descriptive laboratory study. Methods: Healthy male pitchers aged 10 years (n = 22) threw 3 sets of 25 pitches with 12 minutes between sets (3 timepoints). Bilateral ulnohumeral joint gapping was measured by applying a standardized valgus force and utilizing ultrasound imaging. Relative changes in muscle glycogen in the bilateral flexor carpi radialis (FCR), and the flexor digitorum superficialis/flexor carpi ulnaris (FDS/FCU) muscles were measured with ultrasound software and recorded as fuel percentiles. Additional measures obtained included subjective fatigue, strength, ROM, velocity, and accuracy. Results: There were no differences in medial elbow joint-line gapping between the throwing and nonthrowing arms or between timepoints. The throwing arm demonstrated a significant decline in fuel percentile of the FCR from baseline to after 75 pitches ( P = .05). There were no differences across timepoints for FDS/FCU fuel percentile values. Fatigue measurements for both arms were significantly higher at all timepoints compared with baseline ( P ≤ .03). Grip strength of the dominant arm after 75 pitches was decreased significantly compared with after 25 pitches ( P = .02). Conclusion: Although an increase in medial elbow joint gapping was not demonstrated within the recommended 75 pitch count limit in 10-year-olds, a relative decrease in glycogen stores of the flexor-pronator mass did occur, as well as a decrease in grip strength, with increasing subjective fatigue. Clinical Relevance: This study provides a foundation for further objective testing of physiologic changes that occur with pitching to better guide pitch count limits and improve the safety of young athletes. Competing Interests: One or more of the authors has declared the following potential conflict of interest or source of funding: funding for this study was provided by the University of Michigan. M.F.S. has received education payments from Arthrex and Smith+Nephew and hospitality payments from Stryker and Medical Device Business Services. T.M.A. has received education payments from Fujifilm SonoSite, consulting fees from Arthrex, nonconsulting fees from Arthrex, and honoraria from Tenex Health. M.T.F. has received grant support from Encore Medical; education payments from Evolution Surgical; consulting fees from Biorez, Smith+Nephew, and Stryker; nonconsulting fees from Smith+Nephew and Integra LifeSciences; royalties from Smith+Nephew; and hospitality payments from Xiros and Wright Medical. AOSSM checks author disclosures against the Open Payments Database (OPD). AOSSM has not conducted an independent investigation on the OPD and disclaims any liability or responsibility relating thereto. Ethical approval for this study was obtained from the University of Michigan (ref No. HUM00135428). (© The Author(s) 2024.)
Databáze:	MEDLINE
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