Low-load blood flow restricted (BFR) resistance exercise has been suggested to be as effective as moderate and high-load resistance training for increasing muscle size and strength. The purpose of the study was to evaluate the effects of 6 weeks of HL or low-load BFR resistance training on neuromuscular function, strength, and hypertrophy of the knee extensors. Eighteen participants aged 18-22 years old were randomized to one of three training groups: moderate load (ML: 70% of 1 repetition maximum [1-RM]); BFR (20% 1-RM with a vascular restriction set to ~180 mmHg); and a control group (CON) that did not exercise. Participants performed leg extension (LE) and leg press exercises 3 times per week for 6 weeks. Measurements of isometric torque, LE 1-RM, central activation, electrically evoked torque, and muscle volume of the knee extensors were obtained before and after training. Isometric peak torque did not change following the training (p = 0.13). LE 1-RM improved in the ML (34 ± 20%; d = 0.78) and BFR (14 ± 5%; d = 0.67) groups compared to the CON group (0.6 ± 8%; d = 0.09; time x group interaction p = 0.02). Muscle volume increased in the ML (5.6%; d = 0.19) and BFR groups (2.5%; d = 0.09) with no change in the CON group (time x group interaction p = 0.001). There were no changes in central activation and evoked torque in any groups following the training (p > 0.05). Strength and hypertrophy were evident following ML and BFR resistance training programs indicating that both modalities are effective, although ML training appears to be a more potent and efficient. Neuromuscular changes were not evident and warrant more research.

• This study supports the notion that low-load resistance exercise with a blood flow restriction facilitates increases in muscle size and strength.

• The results of this study has implications for elderly and clinical populations who would benefit from gains in muscle size and strength but cannot tolerate the mechanical strain associated with lifting heavy loads.

• The central and peripheral neuromuscular variables measured in this study were not enhanced in either group, which indicates that 1) the neuromuscular factors other than those assessed contribute to training adaptations; or 2) the adaptations of the variables assessed were not apparent at the time of testing.