FINGER STRENGTH DOES NOT DECREASE WITH ROCK CLIMBING TO THE POINT OF FAILURE

Abstract

Experienced rock climbers often identify the hand and fingers as primary areas of failure in competitive climbing. It has been suggested that the inability to maintain a specific finger configuration is the causative factor, however, there is a lack of research regarding fatigue of finger flexor muscle in climbing. PURPOSE To investigate changes in maximum finger force and forearm electromyogram (EMG) that result from performance of a difficult climbing task to the point of failure. METHODS Ten experienced rock climbers (age = 30.1± 13.1 yr) volunteered as subjects. Maximum handgrip strength (MHG) was measured via dynamometer with the best of two trials for the right hand recorded. Finger force (FF) was measured via a piezoelectric force sensor fitted with a plate to accept the first digits of four fingers. Force was applied to the plate/sensor by the fingers of the right hand via a 3-second maximal contraction. Forearm EMG was recorded at 500 Hz from surface electrodes placed 1/3 of the distance from the medial epicondyle of the humerus to the styloid process of the radius and a point 2 cm distal. EMG and force data were acquired simultaneously via a BioPac MP100 system and microcomputer. The raw EMG was integrated (IEMG) via root mean squared. Peak FF measurements were recorded in kg immediately before (pre) and immediately after (post) the subject climbed a repeated series of movements on 45-degree overhanging terrain until the point of a fall or inability to progress. RESULTS FFpre was significantly less than MHG (22.4±6.5 vs 55.6±8.8 kg), however FFpre IEMG and MHG IEMG were not significantly different. Climbers completed a mean of 37±17 hand movements during the climbing task. There were no significant differences between FFpre vs FFpost conditions for peak force or IEMG. CONCLUSION The primary cause of failure during climbing on terrain of the nature employed in this study is not a decrease in the ability to produce concentric finger force.