Low-Load Resistance Training to Volitional Failure Induces Muscle Hypertrophy Similar to Volume-Matched, Velocity...

Area of Science:

• Exercise Physiology
• Muscle Adaptation
• Resistance Training

Background:

• Understanding the optimal parameters for resistance training (RT) is crucial for maximizing muscle hypertrophy and strength.
• Previous research has explored various RT protocols, but direct comparisons between low-load training to volitional failure and velocity fatigue at matched volumes are limited.

Purpose of the Study:

• To compare the acute responses and chronic muscle adaptations between low-load RT to volitional failure (LVoF) and low-load RT to velocity fatigue (LVeF) at equal work volumes.
• To compare these low-load RT protocols against a high-load (HL) RT protocol.

Main Methods:

• Twenty-seven subjects were randomized into three groups: LVoF (40% 1RM to failure), LVeF (40% 1RM to 20% velocity loss), and HL (80% 1RM for 8 reps).
• Participants performed 8 weeks of bench press RT twice weekly.
• Measurements included muscle strength, hypertrophy, endurance, power, acute muscle swelling, and blood lactate levels.

Main Results:

• No significant differences in total work volume were observed between the LVoF and LVeF groups.
• Acute responses (muscle swelling, blood lactate) and chronic adaptations (hypertrophy, strength gain) were similar between LVoF and LVeF.
• Both LVoF and LVeF demonstrated enhanced acute responses and greater chronic endurance gains compared to HL, but lower chronic strength gains.

Conclusions:

• Low-load resistance training to volitional failure induces muscle hypertrophy comparable to volume-matched velocity fatigue.
• Both low-load protocols offer distinct benefits in acute responses and endurance adaptations compared to high-load training, albeit with potentially reduced strength gains.