Hand grip force is often given importance in the study of rock climbing performance. In practice, however, climbing requires production of contact forces via different hand and finger positions. The degree and variability of muscle activation for different hand positions during climbing are unknown. The purpose of this study was to compare EMG responses for six hand positions during a rock climbing movement and to compare these responses to that obtained during a maximum hand grip test. Five experienced climbers signed informed consent to participate in the study. Subjects performed four moves up (UP) and four moves down (DN) on a steep 45-deg. angle with each of six hand positions: crimp (C) with four fingers on a 1 cm edge; pinch (P) with thumb in opposition to fingers; three 2-finger combinations with digits V+IV (2F1), IV+III (2F2), and III+II (2F3); and an open-hand (O) on a 4 cm edge. EMG was recorded via surface electrodes placed 1/3 of the distance from the medial epicondyle of the humerus to the styloid process of the radius and 2 cm distal along the same line. Raw data were recorded for the second UP and second DN moves and rectified using a Biopac system (Tel-100). Prior to climbing, maximum hand grip force (HG) and simultaneous EMG (EMGHG) were obtained from the best of two trials using a Lafayette dynamometer. Mean HG was 53.7±3.4 kg. Times to complete the movements with each hand position varied between 3.1±0.5 and 4.8±0.9 sec, however no significant differences were found. Mean EMG amplitudes for UP, expressed as percentages of EMGHG, were 186±94, 179±56, 262±91, 212±78, 172±48, and 188±73% for C, P, 2F1, 2F2, 2F3, and O respectively and not significantly different (p=0.08 with repeated measures ANOVA). Except for P, all EMG amplitudes were lower for DN than UP, although no significant differences were found. Since all climbing EMG's exceeded the EMGHG, it was concluded that hand grip dynamometry may lack specificity to actual rock climbing.
American College of Sports Medicine; 46th Annual Meeting; Washington State; Convention & Trade Center; June 2-5, 1999
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C-35 POSTER SPORT PERFORMANCE - STRENGTH/AGILITY