title: The effect of intense interval cycle-training on unloading-induced dysfunction and atrophy in the human calf muscle.
abstract: We investigated whether intense interval training on a cycle ergometer would prevent loss of muscle strength and atrophy in the human calf during unilateral lower limb suspension (ULLS). The present study involved 11 healthy men. We defined unloading leg and contralateral leg as ULLS-leg and CONT-leg, respectively. The subjects were divided into 2 groups: one with single-leg cycling training (Tr-UL, n=6); the other as a control (UL, n=5). The Tr-UL group performed an intense 25-min interval cycling training up to 80% of peak oxygen uptake on alternate days during 20-d ULLS. It was found that: 1) in maximal voluntary contraction (MVC) and the cross-sectional area of the planter flexor, there was a significant time- (pre-ULLS and post-ULLS) by-leg (ULLS-leg and CONT-leg) interaction; 2) in voluntary activation during MVC evaluated by the twitch interpolation technique, no significant time-by-leg interaction was detected but the trend of change from before to after ULLS tended to be different between ULLS-leg and CONT-leg; and 3) regarding ULLS-leg, the change in any parameters was not significantly different between the Tr-UL and UL groups. These results suggest that unloading induces dysfunction and atrophy in the human calf and that high-intensity interval training on a cycle ergometer cannot significantly prevent unloading-induced deconditioning in the human calf.
authors.affiliation: Faculty of Health and Medical Sciences, Aichi Shukutoku University, Nagoya, Japan. horinori@asu.aasa.ac.jp
authors.forename: Norio
authors.initials: N
authors.lastname: Hotta
authors.forename: Koji
authors.initials: K
authors.lastname: Ishida
authors.forename: Kohei
authors.initials: K
authors.lastname: Sato
authors.forename: Teruhiko
authors.initials: T
authors.lastname: Koike
authors.forename: Keisho
authors.initials: K
authors.lastname: Katayama
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Akima
mesh_terms: D000328:Adult; D000337:Aerospace Medicine / Q000379:methods; D000704:Analysis of Variance; D001642:Bicycling / Q000502:physiology*; D001696:Biomechanical Phenomena; D005080:Exercise Test; D006801:Humans; D007866:Leg / Q000502:physiology; D008297:Male; D053580:Muscle Strength / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology* / Q000503:physiopathology; D009133:Muscular Atrophy / Q000503:physiopathology* / Q000534:rehabilitation; D019415:Torque