title: The Potential Risk Factors Relevant to Lateral Epicondylitis by Wrist Coupling Posture.
abstract: The use of awkward wrist postures and unskilled techniques might induce lateral epicondylitis. This study thus investigated the effects of wrist deviation combined with extension and movement velocity on the dynamic performances of the wrist muscles during the coupling posture via a custom-made bi-planar isokinetic dynamometer. Thirty subjects were recruited to perform the isokinetic testing. We measured the muscle strengths and activities for the wrist extensors and flexors during concentric and eccentric contractions at three movement velocities, 30°s(-1), 90°s(-1), and 180°s(-1), combined with three wrist postures, neutral position (NP), radial deviation (RD), and ulnar deviation (UD). The root mean square (RMS) of the electromyographic signal in the extensor digitorum communis (EDC), normalized peak torque of extensors, and ratio of normalized peak torque between wrist extensors and flexors, were all greater in the NP than RD and UD in both contractions. The ratio of RMS between EDC and flexor digitorum superficialis (FDS) had a significantly greater value in RD than UD during the concentric contraction. The EDC showed significantly higher activity at the fast velocity in both contractions. Nevertheless, a significantly higher RMS of the electromyographic signal between EDC and FDS and the ratio of strength between wrist extensors and flexors were found at slow velocity in both contractions. The wrist deviation combined with extension and movement velocity of the wrist joint should thus be considered as influential factors which might alter the dynamic performances, and may result in further injury of the elbow joint.
authors.affiliation: Department of Biomedical Engineering, National Cheng Kung University, Tainan, Taiwan.
authors.forename: Su-Ya
authors.initials: SY
authors.lastname: Lee
authors.affiliation: Department of Biomedical Engineering, National Cheng Kung University, Tainan, Taiwan.
authors.forename: Hsiao-Feng
authors.initials: HF
authors.lastname: Chieh
authors.affiliation: Medical Device Innovation Center, National Cheng Kung University, Tainan, Taiwan.
authors.forename: Chien-Ju
authors.initials: CJ
authors.lastname: Lin
authors.affiliation: Department of Orthopedics, National Cheng Kung University Hospital, Tainan, Taiwan.
authors.forename: I-Ming
authors.initials: IM
authors.lastname: Jou
authors.affiliation: Medical Device Innovation Center, National Cheng Kung University, Tainan, Taiwan.|Department of Occupational Therapy, National Cheng Kung University, Tainan, Taiwan.
authors.forename: Li-Chieh
authors.initials: LC
authors.lastname: Kuo
authors.affiliation: Department of Biomedical Engineering, National Cheng Kung University, Tainan, Taiwan.|Medical Device Innovation Center, National Cheng Kung University, Tainan, Taiwan.
authors.forename: Fong-Chin
authors.initials: FC
authors.lastname: Su
mesh_terms: D005260:Female; D006801:Humans; D008297:Male; D053581:Muscle Strength Dynamometer; D009132:Muscles / Q000503:physiopathology; D011187:Posture; D012307:Risk Factors; D013716:Tennis Elbow / Q000503:physiopathology*; D019415:Torque; D014955:Wrist Joint / Q000503:physiopathology*; D055815:Young Adult