Influence of gravity on biomechanics in flywheel squat and leg press. Issue 6 (3rd June 2023)

• Record Type: Journal Article
• Authors: Sjöberg, Maria; Berg, Hans E.; Norrbrand, Lena; Andersen, Michael S.; Gutierrez-Farewik, Elena M.; Sundblad, Patrik; Eiken, Ola
• Is Part Of: Sports biomechanics. Volume 22:Issue 6(2023)
• Page Start: 767
• Page End: 783
• Publication Date: 2023-06-03
• Subjects: Space flight -- musculoskeletal unloading -- countermeasure exercise -- strength training -- inverse dynamics; Biomechanics -- Periodicals; Sports -- Physiological aspects -- Periodicals; Human mechanics -- Periodicals; 617.1027
• DOI: 10.1080/14763141.2020.1761993
• Languages: English
• ISSNs: 1476-3141

Abstract

ABSTRACT: Resistance exercise on Earth commonly involves both body weight and external load. When developing exercise routines and devices for use in space, the absence of body weight is not always adequately considered. This study compared musculoskeletal load distribution during two flywheel resistance knee-extension exercises, performed in the direction of (vertical squat; S) or perpendicular to (horizontal leg press; LP) the gravity vector. Eleven participants performed these two exercises at a given submaximal load. Motion analysis and musculoskeletal modelling were used to compute joint loads and to simulate a weightless situation. The flywheel load was more than twice as high in LP as in S ( p < 0.001). Joint moments and forces were greater during LP than during S in the ankle, hip and lower back ( p < 0.01) but were similar in the knee. In the simulated weightless situation, hip and lower-back loadings in S were higher than corresponding values at Earth gravity ( p ≤ 0.01), whereas LP joint loads did not increase. The results suggest that LP is a better terrestrial analogue than S for knee-extension exercise in weightlessness and that the magnitude and direction of gravity during resistance exercise should be considered when designing and evaluating countermeasure exercise routines and devices for space.