DETECTION OF SUBMAXIMAL EFFORT WITH COMPUTER-ASSISTED GRIP STRENGTH MEASUREMENTS

The purpose of this study was to establish a simple observation to hel p in distinguishing patients who are giving their maximal effort durin g computer-assisted grip strength measurements from those who are not, Preliminary observations had suggested that maximal effort with this grip-strength device was characterized by greater force in the radial digits than the ulnar digits and a small variability in force between individual grasps, These observations were then prospectively analyzed in the following groups: (a) 178 assembly workers tested during a rou tine screening at a computer manufacturing company and during preplace ment physicals; (b) 196 workers with a hand injury or cumulative traum a disorder who were seeking consultation for medical treatment; (c) 55 workers with a hand injury or cumulative trauma disorder being measur ed to determine their return. to work status or impairment rating; and (d) 58 asymptomatic volunteers. The volunteers were instructed to per form the maximal gr ip in the same fashion as the other groups and the n to repeat the test exerting a submaximal effort they estimated to be 50% of their own maximal effort. The results of this study demonstrat ed that there is a highly significant association, P < 0.001, between the presence of a ''total pattern'' (radial over ulnar for ce being le ss than 1.0, unilateral grip variation greater than 15%, and differenc e between the left and right grip variation greater than 5%) and the p resence of submaximal effort during grip-strength measurements.