Effects of glove, orientation, pressure, load, and handle on submaximal grasp force

While the use of gloves often aid in the safety of completing tasks, and in some cases can even increase performance, as occurs with torquing tasks, t here is most often a trade off between increased safety and performance cap ability when donning gloves. This is especially true in the microgravity EV A environment. The objectives of the present program of research were to ex amine grasp force at maximal and submaximal exertions, and to address the p ossibility of a relationship tactility and grasp force. A series of studies were conducted to examine grasp force at the hand/handle interface under a variety of performance conditions. Experiment 1 was conducted to examine t he effect of glove type, pressure differential, and lifted load on grasp fo rce at submaximal exertions. Experiment 2 also examined the effect of glove type and lifted load on submaximal grasp force. In addition, handle size a nd handle orientation were also examined. Experiment 3 was an examination o f the effect of glove type, load lifted, handle size and handle orientation on maximal grasp force. Findings indicated that grasp force was effected b y frictional and load tactile feedback. Consistent with published evidence, there was a strong glove effect at maximal exertions. However, the glove e ffect was marginal at submaximal exertions. This suggests that the neuro-mu scular mechanisms utilized during maximal exertions are differentially appl ied and/or different from those used during submaximal or "just holding" ty pes of exertion. The implications for the designer are discussed.