title: Muscular adaptations to fatiguing exercise with and without blood flow restriction.
abstract: The purpose of this study was to determine the muscular adaptations to low-load resistance training performed to fatigue with and without blood flow restriction (BFR). Middle-aged (42-62 years) men (n = 12) and women (n = 6) completed 18 sessions of unilateral knee extensor resistance training to volitional fatigue over 6 weeks. One limb trained under BFR, and the contralateral limb trained without BFR [free flow (FF)]. Before and after the training, measures of anterior and lateral quadriceps muscle thickness (MTh), strength, power and endurance were assessed on each limb. The total exercise training volume was significantly greater for the FF limb compared with the BFR limb (P<0·001). Anterior quadriceps thickness and muscle function increased following the training in each limb with no differences between limbs. Lateral quadriceps MTh increased significantly more (P<0·05) in the limb trained under BFR (BFR: 3·50 ± 0·61 to 3·67 ± 0·62 cm; FF: 3·49 ± 0·73 to 3·56 ± 0·70 cm). Low-load resistance training to volitional fatigue both with and without BFR is viable options for improving muscle function in middle-aged individuals. However, BFR enhanced the hypertrophic effect of low-load training and reduced the volume of exercise needed to elicit increases in muscle function.
authors.affiliation: Fitchburg State University, Fitchburg, MA, USA.
authors.forename: Christopher A
authors.initials: CA
authors.lastname: Fahs
authors.forename: Jeremy P
authors.initials: JP
authors.lastname: Loenneke
authors.forename: Robert S
authors.initials: RS
authors.lastname: Thiebaud
authors.forename: Lindy M
authors.initials: LM
authors.lastname: Rossow
authors.forename: Daeyeol
authors.initials: D
authors.lastname: Kim
authors.forename: Takashi
authors.initials: T
authors.lastname: Abe
authors.forename: Travis W
authors.initials: TW
authors.lastname: Beck
authors.forename: Daniel L
authors.initials: DL
authors.lastname: Feeback
authors.forename: Debra A
authors.initials: DA
authors.lastname: Bemben
authors.forename: Michael G
authors.initials: MG
authors.lastname: Bemben
mesh_terms: D000222:Adaptation, Physiological; D000328:Adult; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009119:Muscle Contraction; D018763:Muscle Fatigue; D053580:Muscle Strength; D009929:Organ Size; D052097:Quadriceps Muscle / Q000098:blood supply* / Q000000981:diagnostic imaging / Q000502:physiology*; D012039:Regional Blood Flow; D055070:Resistance Training; D013997:Time Factors; D014463:Ultrasonography; D014836:Volition
keywords: low-load; muscle endurance; muscle hypertrophy; muscle power; muscle strength