title: Torque loss induced by repetitive maximal eccentric contractions is marginally influenced by work-to-rest ratio.
abstract: The influence of different work-to-rest (W:R) ratios during fatigue induced by maximal eccentric contractions is unknown. The present study sought to expand the understanding of the task-dependent nature of eccentric contractions, and the associated fatigue, during exercise and acute as well as extended recovery periods. Using a Biodex multi-joint dynamometer, the ankle dorsiflexors of eight men [26 (4) years] were fatigued with 150 maximal eccentric contractions. Set structure was manipulated such that one leg performed 3 sets of 50 repetitions (short rest protocol, SRP), and the other leg performed 15 sets of 10 repetitions (long rest protocol, LRP). A 1-min rest interval separated each set, which resulted in 2 and 14 min of total rest for the SRP and the LRP, respectively. At fatigue, the SRP demonstrated a marginally greater loss of average peak eccentric torque than the LRP ( P<0.05). In the acute period following fatigue, isometric peak torque loss and the degree of low-frequency fatigue (LFF) were not recovered ( P<0.05) and were equivalent for both protocols. Significant impairment of both eccentric and isometric torque was persistent and equal for each protocol at 96 h of recovery ( P<0.05). These findings suggest that the W:R ratio has a modest influence on the fatigue (torque loss) induced by maximal eccentric contractions, but maximal isometric torque during recovery and LFF are insensitive to changes in total rest time.
authors.affiliation: Canadian Centre for Activity and Aging, School of Kinesiology, Faculty of Health Sciences, The University of Western Ontario, St. Joseph's Health Centre Annex, 1490 Richmond Street, N6G 2M3, London, Ontario, Canada.
authors.forename: Chris J
authors.initials: CJ
authors.lastname: McNeil
authors.forename: Brian L
authors.initials: BL
authors.lastname: Allman
authors.forename: T Brock
authors.initials: TB
authors.lastname: Symons
authors.forename: Anthony A
authors.initials: AA
authors.lastname: Vandervoort
authors.forename: Charles L
authors.initials: CL
authors.lastname: Rice
mesh_terms: D000222:Adaptation, Physiological / Q000502:physiology; D000328:Adult; D000843:Ankle Joint / Q000502:physiology*; D015444:Exercise / Q000502:physiology*; D006801:Humans; D007537:Isometric Contraction / Q000502:physiology*; D008297:Male; D018763:Muscle Fatigue / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology*; D010507:Periodicity; D010807:Physical Endurance / Q000502:physiology*; D020127:Recovery of Function / Q000502:physiology; D012146:Rest / Q000502:physiology; D019415:Torque