The effects of forearm fatigue on baseball fastball pitching, with implications about elbow injury.
This study investigated the contribution of flexor muscles to the forearm through fatigue; therefore, the differences in forearm mechanisms on the pitching motion in fastball were analysed. Fifteen baseball pitchers were included in this study. Ultrasonographical examination of participants' ulnar nerve in the cubital tunnel with the elbow extended and at 45°, 90° and 120° of flexion was carried. A three-dimensional motion analysis system with 14 reflective markers attached on participants was used for motion data collection. The electromyography system was applied over the flexor carpi ulnaris, flexor carpi radialis and extensor carpi radialis muscles of the dominant arm. Flexor carpi ulnaris muscle activity showed a significant difference during the acceleration phase, with a peak value during fastball post-fatigue (P = 0.02). Significant differences in the distance between ulnar nerve and medial condyle on throwing arm and non-throwing arm were observed as the distance increased with the elbow movement from 0° to 120° of flexion (P = 0.01). The significant increase of the flexor carpi ulnaris muscle activity might be responsible for maintaining the stability of the wrist joint. The increased diameter might compress the ulnar nerve and cause several pathological changes. Therefore, fatigue in baseball pitchers still poses a threat to the ulnar nerve because the flexor carpi ulnaris and flexor carpi radialis all originate from the medial side of the elbow, and the swelling tendons after fatigue might be a key point.
a Institute of Physical Education, Health & Leisure Studies , National Cheng Kung University , Tainan , Taiwan.
Lin-Hwa
LH
Wang
b Physical Education Office , Kun Shan University , Tainan , Taiwan.
Kuo-Cheng
KC
Lo
c Department of Orthopaedics, National Cheng Kung University Hospital, College of Medicine , National Cheng Kung University , Tainan , Taiwan.
I-Ming
IM
Jou
d Institute of Occupational Therapy , National Cheng Kung University , Tainan , Taiwan.
Li-Chieh
LC
Kuo
e Department of Orthopaedics, National Cheng Kung University Hospital, College of Medicine, Department of Biomedical Engineering , National Cheng Kung University , Tainan , Taiwan.
Ta-Wei
TW
Tai
f Department of Biomedical Engineering , National Cheng Kung University , Tainan , Taiwan.
Fong-Chin
FC
Su
D001484:Baseball / Q000502:physiology*; D001696:Biomechanical Phenomena; D004550:Elbow / Q000294:innervation; D004576:Electromyography; D005221:Fatigue / Q000503:physiopathology*; D005542:Forearm / Q000502:physiology / Q000503:physiopathology*; D006801:Humans; D018482:Muscle, Skeletal / Q000502:physiology / Q000503:physiopathology*; D016059:Range of Motion, Articular; D014459:Ulnar Nerve / Q000000981:diagnostic imaging / Q000503:physiopathology; D014463:Ultrasonography; D014955:Wrist Joint / Q000502:physiology / Q000503:physiopathology; D055815:Young Adult; D000092464:Elbow Injuries
Biomechanics; motion; ulnar nerve; ultrasonography; upper extremity