Handgrip Strength with the Bare Hand and in the NASA Spacesuit Glove

Abstract

This study examined handgrip strength with the bare and spacesuit-gloved hand, in three hand and two elbow positions. Sixteen subjects from the suited-subject pool at NASA/Johnson Space Center gripped a hand dynamometer encased in a vacuum chamber designed to simulate the pressure differential of the spacesuit in space. With the bare hand (at one atmosphere), there was an effect for hand position and a hand-position x elbow-position interaction. With the spacesuit-gloved hand, there was only an effect for hand position. Two different pressure differentials (psid) were used: the glove at 0.5 psid was responsible for a 35% grip decrement (when compared to bare handgrip); the glove at 4.3 psid (normal operating pressure) was responsible for a 42% grip decrement. Bare and gloved-handgrip were positively correlated with hand size, body weight, height, and forearm circumference. Post-hoc, subjects were grouped by hand size; the four subjects in the XL hand-size group lost an average of 17% in grip in the glove at 4.3 psid (when compared to the glove at 0.5 psid); the L group lost 12%; the M group lost 9%; and the S hand-size group lost less than 1%. The larger the hand, the greater was the grip strength decrement due to increased pressure in the glove.