O Bock1. 1. Institute for Space and Terrestrial Science, North York, Canada.
Abstract
BACKGROUND: Little is known about the effects of changed gravity on the execution of grasping movements, even though such movements play an important role in normal motor behavior of humans. HYPOTHESIS: The formation of an adequate grip aperture is impaired in changed gravity. METHOD: During parabolic flight, five subjects grasped mirror-viewed virtual targets with their thumb and index finger. From their video-taped responses, we determined grip aperture as the distance between the two fingertips. RESULTS: In changed gravity, the final grip aperture was about 15% smaller than in normal gravity, and the peak grip aperture was about 30% less modulated by target size. Both findings were similar in hyper-G and in micro-G. CONCLUSIONS: We conclude that (virtual) grasping in changed gravity is affected by a deterioration of visual and/or proprioceptive signals, or by the increased computational burden of controlling movements in unusual force environments.
BACKGROUND: Little is known about the effects of changed gravity on the execution of grasping movements, even though such movements play an important role in normal motor behavior of humans. HYPOTHESIS: The formation of an adequate grip aperture is impaired in changed gravity. METHOD: During parabolic flight, five subjects grasped mirror-viewed virtual targets with their thumb and index finger. From their video-taped responses, we determined grip aperture as the distance between the two fingertips. RESULTS: In changed gravity, the final grip aperture was about 15% smaller than in normal gravity, and the peak grip aperture was about 30% less modulated by target size. Both findings were similar in hyper-G and in micro-G. CONCLUSIONS: We conclude that (virtual) grasping in changed gravity is affected by a deterioration of visual and/or proprioceptive signals, or by the increased computational burden of controlling movements in unusual force environments.
Authors: Ajitkumar P Mulavara; Brian T Peters; Chris A Miller; Igor S Kofman; Millard F Reschke; Laura C Taylor; Emily L Lawrence; Scott J Wood; Steven S Laurie; Stuart M C Lee; Roxanne E Buxton; Tiffany R May-Phillips; Michael B Stenger; Lori L Ploutz-Snyder; Jeffrey W Ryder; Alan H Feiveson; Jacob J Bloomberg Journal: Med Sci Sports Exerc Date: 2018-09 Impact factor: 5.411