“BFR and Muscle Mitochondrial Oxidative Capacity”
Blood flow restricted (BFR) exercise has been shown to improve skeletal muscle adaptations to resistance exercise. BFR uses blood pressure cuffs (i.e., tourniquets) to reduce skeletal muscle blood flow during resistance exercise. One benefit of BFR is that skeletal muscle adaptations to resistance exercise training including muscle hypertrophy and increases in strength can be achieved at lower-loads (e.g., 25-30% 1RM), that are often comparable to more traditional resistance training loads (70-85% 1RM). However, the impact that low-load BFR resistance exercise has on muscle quality and bioenergetics is unknown. The present study will examine the impact of 6 weeks of low-load, single-leg resistance exercise training with or without personalized BFR on measures of muscle mass, strength, quality, and mitochondrial bioenergetics. The investigators will recruit and study up to 30, previously sedentary, healthy, college-aged adults (18-40 years). The investigators will measure muscle mass using Dual Energy X-Ray Absorptiometry and muscle strength and endurance using isokinetic testing. The investigators will normalize knee extensor strength to lower limb lean mass to quantify muscle quality. The investigators will also use near infrared spectroscopy (NIRS) to measure mitochondrial oxidative capacity in the vastus lateralis. Finally, the investigators will measure markers of systemic inflammation and markers of muscle damage using commercially available ELISA assays.
Behavioral - Low Load Resistance Exercise
Subjects allocated to Low Load Resistance Exercise will undergo 5 weeks of single-legged low load (25%) resistance exercise. Subjects will then perform 4 sets of 30, 15, 15 and 15 repetitions at 25% of their 1RM for the single-legged leg press and single-legged knee extensions. Their contralateral leg will serve as within subject control.
Behavioral - Low Load Resistance Exercise + BFR
Subjects allocated to Low Load Resistance Exercise + BFR will undergo 5 weeks of single-legged low load (25%) resistance exercise with blood flow restriction (60% occlusion pressure). Subjects will then perform 4 sets of 30, 15, 15 and 15 repetitions at 25% of their 1RM for the single-legged leg press and single-legged knee extensions. Their contralateral leg will serve as within subject control.
Impact of Low-Intensity Resistance Exercise With and Without Blood Flow Redistricted (BFR) on Muscle Mitochondrial Oxidative Capacity