Pignanelli 2019 Am J Physiol Regul Integr Comp Physiol
|Pignanelli C, Petrick HL, Keyvani F, Heigenhauser GJF, Quadrilatero J, Holloway GP, Burr JF (2019) Low-load resistance training to task-failure with and without blood flow restriction: muscular functional and structural adaptations. Am J Physiol Regul Integr Comp Physiol 318:R284-95.|
Abstract: The application of blood flow restriction (BFR) during resistance exercise is increasingly recognized for its ability to improve rehabilitation and as an effective method for increasing muscular hypertrophy and strength amongst healthy populations. However, direct comparison of the skeletal muscle adaptations to low-load resistance exercise (LL-RE) and low-load blood flow restriction resistance exercise (LL-BFR) performed to task-failure are lacking. Using a within-subject design, we examined whole-muscle group and skeletal muscle adaptations to 6-weeks of LL-RE and LL-BFR training to repetition failure. Both types of training had similar muscle strength and size outcomes despite ~33% lower total exercise volume (load x repetition) with LL-BFR (LL-RE: 28,544±1,771kg vs. LL-BFR: 18,949±1,541kg, p=0.004). Following training, only LL-BFR improved the average power output throughout the midportion of a voluntary muscular endurance task. Specifically, LL-BFR training sustained an 18% greater power output from baseline and had a greater change from baseline compared to LL-RE (19±3 W vs. 3±4 W, p=0.008). This improvement occurred despite histological analysis revealing similar increases in capillary content of type I muscle fibers following LL-RE and LL-BFR training, which was primarily driven by increased capillary contacts (Pre: 4.53±0.23 vs. LL-RE: 5.33±0.27 and LL-BFR: 5.17±0.25, both p<0.05). Moreover, maximally-supported mitochondrial respiratory capacity increased only in the LL-RE leg by 30% from baseline (p=0.006). Overall, low-load resistance training increased indices of muscle oxidative capacity and strength, which were not further augmented with the application of BFR. However, performance on a muscular endurance test was improved following BFR training.
Labels: MiParea: Respiration, Exercise physiology;nutrition;life style
Organism: Human Tissue;cell: Skeletal muscle Preparation: Permeabilized tissue Enzyme: Complex I, Complex II;succinate dehydrogenase, Complex III, Complex IV;cytochrome c oxidase, Complex V;ATP synthase
Coupling state: LEAK, OXPHOS Pathway: N, NS HRR: Oxygraph-2k