Effects of Low- vs. High-Load Resistance Training on Muscle Strength and Hypertrophy in Well-Trained Men.
Level 2 - randomized trial
Individual randomized controlled trial
PubMed 25853914 · doi:10.1519/JSC.0000000000000958
What was done
Eighteen resistance-trained young men were matched by baseline strength and randomly assigned to either a low-load training group (LL: 25–35 repetitions per set, n = 9) or a high-load training group (HL: 8–12 repetitions per set, n = 9). Both groups completed 3 sets of 7 exercises targeting major muscle groups, 3 days per week for 8 weeks. Muscle thickness (elbow flexors, elbow extensors, quadriceps femoris), maximal strength (1RM back squat and bench press), and upper-body muscular endurance (50% 1RM bench press to failure) were evaluated.
What was found
Both HL and LL elicited significant, statistically similar increases in muscle thickness for the elbow flexors (5.3% vs. 8.6%), elbow extensors (6.0% vs. 5.2%), and quadriceps femoris (9.3% vs. 9.5%). Back squat 1RM improved significantly more with HL than LL (19.6% vs. 8.8%), with a trend for greater increases in 1RM bench press (6.5% vs. 2.0%). Muscular endurance improved significantly more in LL compared to HL (16.6% vs. -1.2%).
Why it matters
This study shows that when sets are taken to failure, low-load and high-load resistance training produce similar muscle hypertrophy in trained men, though strength and endurance adaptations remain load-specific.
Limits
The sample size was very small (n = 18 total; 9 per group), which limits statistical power for detecting smaller effect differences. The study lasted only 8 weeks and included only young, resistance-trained men, so findings may not generalize to women, older individuals, or untrained populations. Nutritional intake was not detailed in the abstract.
Cited by
- supports Resistance training produces similar amounts of muscle hypertrophy across a wide loading spectrum, including up to 30 to 40 repetitions per set.
- supports Brad Schoenfeld's lab conducted a resistance training study comparing heavy and light loads in resistance-trained subjects and found no difference in muscle hypertrophy.