title: Progressive adaptation in physical activity and neuromuscular performance during 520d confinement.
abstract: To understand whether prolonged confinement results in reductions in physical activity and adaptation in the musculoskeletal system, six subjects were measured during 520 d isolation in the Mars500 study. We tested the hypothesis that physical activity reduces in prolonged confinement and that this would be associated with decrements of neuromuscular performance. Physical activity, as measured by average acceleration of the body's center of mass ("activity temperature") using the actibelt® device, decreased progressively over the course of isolation (p<0.00001). Concurrently, countermovement jump power and single-leg hop force decreased during isolation (p<0.001) whilst grip force did not change (p≥0.14). Similar to other models of inactivity, greater decrements of neuromuscular performance occurred in the lower-limb than in the upper-limb. Subject motivational state increased non-significantly (p = 0.20) during isolation, suggesting reductions in lower-limb neuromuscular performance were unrelated to motivation. Overall, we conclude that prolonged confinement is a form of physical inactivity and is associated with adaptation in the neuromuscular system.
authors.affiliation: Centre of Muscle and Bone Research, Charité Universitätsmedizin Berlin, Berlin, Germany. belavy@gmail.com
authors.forename: Daniel L
authors.initials: DL
authors.lastname: Belavý
authors.forename: Ulf
authors.initials: U
authors.lastname: Gast
authors.forename: Martin
authors.initials: M
authors.lastname: Daumer
authors.forename: Elena
authors.initials: E
authors.lastname: Fomina
authors.forename: Rainer
authors.initials: R
authors.lastname: Rawer
authors.forename: Hans
authors.initials: H
authors.lastname: Schießl
authors.forename: Stefan
authors.initials: S
authors.lastname: Schneider
authors.forename: Harald
authors.initials: H
authors.lastname: Schubert
authors.forename: Cristina
authors.initials: C
authors.lastname: Soaz
authors.forename: Dieter
authors.initials: D
authors.lastname: Felsenberg
mesh_terms: D000222:Adaptation, Physiological / Q000502:physiology*; D000328:Adult; D006801:Humans; D035002:Lower Extremity / Q000502:physiology; D008297:Male; D009119:Muscle Contraction; D018482:Muscle, Skeletal / Q000502:physiology*; D012149:Restraint, Physical / Q000502:physiology*
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