Influence of depth on the manual dexterity of free divers: A comparison between open sea and pressure chamber testing.

Abstract

Using a compression chamber, Kiessling and Maag (1962) showed a decline in manual dexterity at a pressure simulating 100 ft. of water. Impairment was slight (7.9%) and was assumed to be of little practical importance. The present study examines this conclusion by testing divers in the water. The manual dexterity and tactile sensitivity of 12 free divers were tested above the surface, and at 10 and 100 ft. below the surface. The dexterity test took 28% longer at 10 ft. and 49% longer at 100 ft. than on the surface, the differences between all conditions being significant (p<.005). Tactile sensitivity did not change. Replication in a dry pressure chamber showed an impairment of less than 6%, though reliable (p < .05) was significantly smaller than that shown in the open sea (p<.05). Conclusions are: the impairment of manual dexterity at depth is considerable when tested under water and it is unwise to generalize from pressure chamber experiments to under water performance.