The purpose of this study was to examine whether repetitive muscle tasks in low weight load might influence the fatigue of forearm muscles, and to identify ergonomic risk factors of forearm muscle fatigue in these tasks. Sixteen healthy male volunteers performed eight wrist extensions in different frequency, weight and angle loads while being instructed to keep a dominant upper limb posture as constant as possible. Surface electromyograph (sEMG) was recorded from right extensors digitorium (ED), flexor carpi radialis (FCR), flexor carpi ulnaris (FCU) and extensor carpi ulnaris (ECU) during the task performance. Our results showed that mean power frequency (MPF) and median frequency (MF) values of ED, FCR and FCU were significantly lower (P<0.05) at high frequency load level than at low load level. However, MPF and MF values of ED were significantly lower (P<0.01) in higher load groups of frequency, angle and weight than in lower load groups. These results indicated that the fatigue of muscles varied in the same task, and the number-one risk factor of ECU, ED and FCR was angle load.
Cumulative Trauma Disorders/complications ; Cumulative Trauma Disorders/*physiopathology ; Electromyography ; Forearm/*physiology ; Muscle Fatigue/*physiology ; Muscle, Skeletal/*physiopathology ; Young Adult

A spontaneous rupture of the extensor pollicis longus (EPL) tendon is associated with rheumatoid arthritis, fractures of the wrist, systemic or local steroids and repetitive, and excessive abnormal motion of the wrist joint. The authors encountered a case of a spontaneous rupture of the EPL tendon. The patient had no predisposing factors including trauma or steroid injection. Although the patient had a positive rheumatoid factor, he did not demonstrate other clinical or radiological findings of rheumatoid arthritis. During surgery, the EPL tendon was found to be ruptured at the extensor retinaculum (third compartment). Reconstruction of the extensor tendon using the palmaris longus tendon was performed. At the 18-month follow-up, the patient showed satisfactory extension of the thumb and 40degrees extension and flexion at the wrist.
Adult ; Cumulative Trauma Disorders/*complications ; Humans ; Male ; Occupational Diseases/*complications ; Rupture/etiology/surgery ; Tendon Injuries/*etiology/*surgery

This report describes a 22-yr-old professional golfer with acute calcific periarthritis of the proximal interphalangeal joint of the 4th finger. We considered that the major cause for this condition may be the repeated minor traumas to the affected site. Also, since this condition is self-limiting, a correct diagnosis is required to avoid unnecessary tests and surgery.
Acute Disease ; Adult ; Arthralgia/diagnosis/etiology ; Calcinosis/*complications/*radiography ; Cumulative Trauma Disorders/complications/radiography ; Finger Injuries/*complications/*radiography ; Golf/*injuries ; Humans ; Male ; Periarthritis/*etiology/*radiography

Iliotibial band (ITB) friction syndrome is a common overuse injury typically seen in the active athlete population. A nodular lesion on the inner side of the ITB as an etiology or an accompanying lesion from friction syndrome has been rarely reported. A 45-year-old male presented with recurrent pain and a movable nodule at the lateral joint area, diagnosed as ITB friction syndrome. The nodule was confirmed as a rare intra-articular fibroma of the tendon sheath (FTS) on the basis of histopathologic findings. We describe the MRI findings, arthroscopic and pathologic features, in this case of intra-articular FTS presenting with ITB friction syndrome.
Cumulative Trauma Disorders/complications/*diagnosis ; Fibroma/*etiology ; Friction ; Humans ; Iliotibial Band Syndrome/complications/*diagnosis ; Knee Joint/*pathology ; Magnetic Resonance Imaging ; Male ; Middle Aged ; Pain/etiology ; Tendons/*pathology