Updated on 2024/10/07

Affiliation
Faculty of Sport Sciences, School of Sport and Sciences
Job title
Assistant Professor(without tenure)
Degree
Ph.D ( 2024.03 Waseda University )

Research Experience

  • 2024.04
    -
    Now

    Waseda University   Faculty of Sport Sciences   Assistant professor

  • 2023.10
    -
    2024.03

    Waseda University   Institute for Sport Sciences   Research assistant

  • 2019.04
    -
    2023.09

    Waseda University   School of Sport Sciences   Teaching Assistant

  • 2021.09
    -
    2023.07

    Waseda University   Global Education Center   Teaching Assistant

Education Background

  • 2019.04
    -
    2023.09

    Waseda University   Graduate School of Sport Sciences  

  • 2017.04
    -
    2019.03

    Waseda University   Graduate School of Sport Sciences  

  • 2013.04
    -
    2017.03

    Waseda University   School of Sport Sciences  

Professional Memberships

  • 2022
    -
    Now

    日本バイオメカニクス学会

  • 2021
    -
    Now

    日本整形外科スポーツ医学会

  • 2021
    -
    Now

    日本体育・スポーツ・健康学会

  • 2018
    -
    Now

    日本トレーニング科学会

  • 2023
    -
    2024

    American College of Sports Medicine

Research Areas

  • Sports sciences

Research Interests

  • Elbow muscular varus strength

  • Injury prevention

  • Baseball

  • Biomechanics

 

Papers

  • A novel method intersecting three-dimensional motion capture and medial elbow strength dynamometry to assess elbow injury risk in baseball pitchers

    Toshimasa Yanai, Kengo Onuma, Ryan L. Crotin, Daisuke Monda

    Scientific Reports   13 ( 1 )  2023.12

     View Summary

    In baseball pitching, resultant elbow varus torque reaches the peak value of 50–120 N m, exceeding the joint failure limit that risks damage to the ulnar collateral ligament (UCL). In-vivo methodology is lacking to assess whether pitchers have sufficient muscular strength to shield UCL and how strongly the elbow musculature must contract to minimize valgus loading on UCL. This study introduces a method to assess relative percentages of muscular varus strength required to unload the UCL. The maximum voluntary isometric varus strength (MVIVS) produced by the medial elbow musculature and the maximum resultant varus torques at elbow in pitching fastballs and other types were measured for two professional pitchers. Simulation was conducted to determine the relative percentages of MVIVS required to unload the UCL to varying degrees and the impact of athletes’ previous UCL reconstruction on the relative percentages was examined. The maximum resultant varus torque in pitching was found to range 72–97%MVIVS depending on the type of pitch. The elbow musculature had to produce 21–49%MVIVS to avoid acute failure of intact UCL whereas the corresponding requirements were 39–63%MVIVS for UCL reconstructed joint. The method offers new insight into baseball pitcher’s training/rehabilitation and physical assessment to reduce the risk of UCL injury.

    DOI PubMed

    Scopus

    1
    Citation
    (Scopus)
  • A method for measuring muscle strength in restraining valgus joint angulation: Elbow varus muscle strength against valgus loading

    Kengo Onuma, Toshimasa Yanai

    Journal of Biomechanics   147  2023.01

    Authorship:Lead author

     View Summary

    Skeletal muscle works as a dynamic joint stabilizer, assisting the underlying ligaments in restricting joint angulation by actively resisting external loads. Despite its clinical importance, little is known about the muscle strength required to produce torque to help ligaments restrict joint angulation within the physiological range permitted by the joint structure. In this study, we introduce a method for measuring the strength of the elbow musculature in restraining valgus angulation and present the values obtained in 20 healthy young men. Each participant was fastened to a Biodex dynamometer, with the elbow joint flexed to 90° and the varus-valgus axis aligned to the dynamometer's rotation axis. Maximal voluntary isometric ramp contraction of shoulder internal rotators was performed while the humeroulnar joint gap was monitored with an ultrasound apparatus. The largest torque recorded while the humeroulnar joint gap did not exceed a predetermined individualized threshold was considered to be the elbow varus strength of the participant. The elbow varus strength of the dynamic stabilizer was found to be 41 ± 12 Nm, which agreed with the value estimated by our musculoskeletal model. The inter-operator reliability test indicated excellent reliability (ICC (2,1) = 0.91). These findings suggest that the present method is valid for measuring the strength of the elbow musculature in restraining the valgus angulation. Measurements of this aspect of strength are expected to provide insights for understanding and preventing elbow injuries.

    DOI PubMed

    Scopus

    2
    Citation
    (Scopus)

Presentations

  • Elbow Varus Muscle Strength Resisting Valgus Loading In Young Adult Men Including Baseball Pitchers

    Onuma, Kengo, Yanai, Toshimasa

    2023 Annual Meeting and World Congresses 

    Presentation date: 2023.05

  • 簡便な計測項目を用いて肘内反筋力を推測する試みーベイズの定理を応用して

    小沼憲吾, 矢内利政

    第28回日本バイオメカニクス学会大会 

    Presentation date: 2022.11

  • 筋はどれだけの肘関節外反荷重に耐えられるのか?-外反可動域を制限する筋力を計る

    小沼憲吾, 矢内利政

    第71回日本体育・スポーツ・健康学会 

    Presentation date: 2021.09

  • 野球選手の投能力を向上させる競技特異的なトレーニングの提案-投球肢位で慣性負荷をかけた内外旋エクササイズの特異性検証

    小沼憲吾, 矢内利政

    第32回日本トレーニング科学会 

    Presentation date: 2019.10

  • Biomechanical characteristics of shoulder internal-rotation exercise with an inertial exercise trainer : Is it suitable for baseball throwing?

    Onuma, Kengo, Yanai, Toshimasa

    Katholic University Leuven-Waseda International Workshop 

    Presentation date: 2019.03

  • Impulse Trainerを用いた慣性トレーニングは投球動作の上肢運動を模倣できるか?-トレーニング動作の特異性検証

    小沼憲吾, 矢内利政

    第31回日本トレーニング科学会 

    Presentation date: 2018.10

▼display all

Research Projects

  • 野球選手における肘障害の予防法開発に向けた挑戦―筋はどれだけ肘を守れているのか?

    ヤマハ発動機スポーツ振興財団  スポーツチャレンジ助成

    Project Year :

    2020.04
    -
    2021.03
     

    小沼憲吾

Misc

  • Elbow Varus Muscle Strength Resisting Valgus Loading In Young Adult Men Including Baseball Pitchers

    Kengo Onuma, Toshimasa Yanai

    Medicine and Science in Sports and Exercise   55 ( 9S ) 58 - 58  2023.09

    DOI

  • 筋はどれだけの肘関節外反荷重に耐えられるのか?-外反可動域を制限する筋力を計る

    小沼憲吾, 矢内利政

    日本体育学会大会予稿集   71   300 - 300  2021

    J-GLOBAL

  • 野球選手の投能力を向上させる競技特異的なトレーニングの提案-投球肢位で慣性負荷をかけた内外旋エクササイズの特異性検証

    小沼憲吾, 矢内利政

    Journal of Training Science for Exercise and Sport   31 ( 4 ) 221 - 221  2019

    J-GLOBAL

  • Impulse Trainerを用いた慣性トレーニングは投球動作の上肢運動を模倣できるか?-トレーニング動作の特異性検証

    小沼憲吾, 矢内利政

    Journal of Training Science for Exercise and Sport   30 ( 3 )  2018

    J-GLOBAL

 

Syllabus

Teaching Experience

  • スポーツ教養演習Ⅲ

    早稲田大学  

    2024.04
    -
    Now
     

  • スポーツ教養演習Ⅱ

    早稲田大学  

    2024.04
    -
    Now
     

  • スポーツ教養演習Ⅰ

    早稲田大学  

    2024.04
    -
    Now
     

 

Social Activities

  • ハートネットTV-パラマニア車いすバスケットボール

    NHK  ハートネットTV 

    2019.11
    -