title: The effect of sleep deprivation and exercise load on isokinetic leg strength and endurance.
abstract: Isokinetic leg strength and fatigue were measured in 24 male U.S. Marine Corps volunteers in a simulated sleep loss and unusually heavy work scenario. Knee extension and flexion peak torque (PT) were measured at three isokinetic speeds (1.57, 2.62 and 3.66 rad.s-1) followed by 45 consecutive maximal reciprocal contractions at 3.14 rad.s-1 to measure fatigue index (FI). All subjects were retested 2 days later following 30-h sleep deprivation (SD). The exercise group (n = 12) spent 25 1-h sessions performing computer tasks, filling out questionnaires and walked 1.61 km with a 50% gross body mass pack load, during each of the 25 sessions. The control group (n = 12) did likewise but did not exercise. Repeated measures ANOVA indicated that flexion PT at 1.57 rad.s-1 decreases (P < 0.013) after SD. Exercise did not affect FI but did decrease PT. It was concluded that carrying a 50% load produces decrements in PT for both extension and flexion but more so for flexion. SD affected PT but had no effect on FI.
authors.affiliation: Exercise Physiology Laboratory, University of Kentucky, Lexington 40506-0219, USA.
authors.forename: R
authors.initials: R
authors.lastname: Bulbulian
authors.forename: J H
authors.initials: JH
authors.lastname: Heaney
authors.forename: C N
authors.initials: CN
authors.lastname: Leake
authors.forename: A A
authors.initials: AA
authors.lastname: Sucec
authors.forename: N T
authors.initials: NT
authors.lastname: Sjoholm
mesh_terms: D003402:Creatine Kinase / Q000097:blood; D015444:Exercise / Q000502:physiology*; D006801:Humans; D007770:L-Lactate Dehydrogenase / Q000097:blood; D007866:Leg; D008297:Male; D009119:Muscle Contraction; D018763:Muscle Fatigue; D018482:Muscle, Skeletal / Q000502:physiology*; D010807:Physical Endurance / Q000502:physiology*; D012892:Sleep Deprivation / Q000502:physiology*
chemical_list: D007770:L-Lactate Dehydrogenase; D003402:Creatine Kinase