Influence of Maximal or Submaximal Effort on the Load Distribution of the Hand Analyzed by Manugraphy

Purpose This study aims to investigate if the hands' load-distribution pattern differs during maximal and submaximal grip. Methods Fifty-four healthy subjects used the 200-mm Manugraphy cylinder to assess the load-distribution pattern of both hands. On 2 testing days, the subjects performed grip-force testing: 1 hand with maximal effort and the other with submaximal effort. Sides changed for the second testing day. The whole contact area of the hand was sectioned into 7 anatomical areas, and the percent contribution of each area, in relation to the total load applied, was calculated. Maximal and submaximal efforts were compared across the 7 areas in terms of load contributions. Results Comparing maximum effort of the left and right hand, the load distribution was very similar without statistically significant differences between the corresponding areas. Comparing the maximal and the submaximal effort for each hand, 4 (left) and 5 (right) of the 7 corresponding areas showed statistically significant differences. Comparing the right hand, performing with maximal effort, with the left hand, performing with submaximal effort, 5 areas varied significantly. With the right hand performing submaximal effort, all 7 anatomical areas were significantly different. Conclusions The load distribution of a healthy hand is different when performing with submaximal effort compared with maximal effort. To analyze a hand's load-distribution pattern, the opposite hand can be used as a reference. Copyright (C) 2018 by the American Society for Surgery of the Hand. All rights reserved.