Evidence map›Paper›PMID 42305429›Full record

ArticleJSES international2026

Relation between forearm flexor-pronator muscle elasticity and ulnar collateral ligament laxity of the elbow joint in high school pitchers with and without medial elbow tenderness: evaluation using shear wave elastography.

Tsuyoshi Tajika, Hitoshi Shitara, Yuhei Hatori, Koichiro Yanai, Tsuyoshi Sasaki, Noritaka Hamano, Masataka Kamiyama, Ryosuke Miyamoto, Shinsuke Arisawa, Yusuke Tomomatsu and 4 more

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Article in JSES international, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.

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1 · What the graph read from it

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2 · The registry

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4 · The record

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5 · Who and what money

Authors and funding

14 authors.

Tsuyoshi TajikaGraduate School of Health Sciences, Gunma University, Maebashi, Gunma, Japan.
Hitoshi ShitaraDepartment of Orthopaedic Surgery, Gunma University Graduate School of Medicine, Maebashi, Gunma, Japan.
Yuhei HatoriDepartment of Orthopaedic Surgery, Gunma University Graduate School of Medicine, Maebashi, Gunma, Japan.
Koichiro YanaiDepartment of Orthopaedic Surgery, Gunma University Graduate School of Medicine, Maebashi, Gunma, Japan.
Tsuyoshi SasakiDepartment of Orthopaedic Surgery, Gunma University Graduate School of Medicine, Maebashi, Gunma, Japan.
Noritaka HamanoDepartment of Orthopaedic Surgery, Gunma University Graduate School of Medicine, Maebashi, Gunma, Japan.
Masataka KamiyamaDepartment of Orthopaedic Surgery, Gunma University Graduate School of Medicine, Maebashi, Gunma, Japan.
Ryosuke MiyamotoDepartment of Orthopaedic Surgery, Gunma University Graduate School of Medicine, Maebashi, Gunma, Japan.
Shinsuke ArisawaDepartment of Orthopaedic Surgery, Gunma University Graduate School of Medicine, Maebashi, Gunma, Japan.
Yusuke TomomatsuDepartment of Orthopaedic Surgery, Gunma University Graduate School of Medicine, Maebashi, Gunma, Japan.
Kazuhiro InomataDepartment of Orthopaedic Surgery, Gunma University Graduate School of Medicine, Maebashi, Gunma, Japan.
Masaaki SakamotoDepartment of Physical Therapy, Takasaki University of Health and Welfare, Takasaki, Gunma, Japan.
Kenji TakagishiDepartment of Orthopaedic Surgery, Sada Hospital, Fukuoka, Fukuoka, Japan.
Hirotaka ChikudaDepartment of Orthopaedic Surgery, Gunma University Graduate School of Medicine, Maebashi, Gunma, Japan.

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

Background: The forearm flexor-pronator muscle contributes to the dynamic stabilizer against valgus stress at the elbow during pitching motion. This study used shear wave ultrasonography to assess the relation between the elasticity of each forearm flexor-pronator muscle and the laxity of the ulnar collateral ligament (UCL) of the elbow joint in high school pitchers with and without medial elbow tenderness. Methods: One hundred and fifteen high school baseball pitchers (average age 16.5 years) underwent a medical checkup during the off-season of 2022. We investigated instances of medial elbow tenderness on the pitching side at that medical check. The 115 participants were divided into 2 groups: 25 pitchers with medial elbow tenderness (medial elbow tenderness group) and 90 without medial elbow tenderness (nonmedial elbow tenderness group). The shear wave velocities of the pronator teres, flexor carpi radialis, flexor carpi ulnaris, flexor digitorum superficialis (FDS), flexor digitorum profundus, and the common flexor-pronator muscles were measured as the index of muscle elasticity using shear wave ultrasonography. Ultrasound examinations were conducted with and without gravity valgus stress of the medial aspect of the bilateral elbows. We compared the elasticity of the forearm flexor-pronator muscle and the degree of laxity of the UCL of the elbow between the 2 groups. Also, we analyzed the relation between the elasticity of each forearm flexor-pronator muscle and the laxity of the UCL of the elbow between the 2 groups. Results: Between the 2 groups, no significant difference was found for any forearm flexor-pronator muscle of the throwing side. In the group without medial elbow tenderness, a weak but significant negative correlation was observed between the shear wave velocity of the FDS and the medial ulnohumeral joint width with and without gravity stress on the throwing side (r = -0.24, Conclusion: Our findings suggest that higher elasticity of the FDS may be associated with a modest reduction in UCL laxity, suggesting it may play a limited role in dynamic stabilization.

Indexed as

BaseballElbowForearm flexor–pronator muscleInstabilityPitcherShear wave elastographyUlnar collateral ligamentUlnohumeral joint

Identifiers

PMID42305429
PMCPMC13266163

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.