High Resistance-Training Volume Enhances Muscle Thickness in Resistance-Trained Men.
Level 2 - randomized trial
Individual randomized controlled trial
PubMed 31868813 · doi:10.1519/JSC.0000000000003413
What was done
Twenty-seven resistance-trained men were pair-matched based on baseline strength and randomly assigned to one of three 8-week resistance training volume protocols: 16 weekly sets per muscle group (G16, n = 9), 24 weekly sets (G24, n = 9), or 32 weekly sets (G32, n = 9). All other resistance training variables (exercise selection, order, frequency, repetition range, rest intervals) were held constant. Pre- and post-intervention measurements evaluated maximal strength (1RM for bench press and parallel back squat) and muscle thickness of the biceps brachii, triceps brachii, and vastus lateralis.
What was found
The abstract does not report specific numeric values or confidence intervals. It reports that all three groups experienced increases in bench press 1RM, back squat 1RM, and muscle thickness in the biceps brachii, triceps brachii, and vastus lateralis. The magnitude of increase in lower-body 1RM and vastus lateralis muscle thickness was greater with 32 sets per week than with 16 sets per week. Triceps brachii muscle thickness increases were also greater with 32 sets compared to 16 sets.
Why it matters
This study provides dose-response evidence in trained individuals suggesting that higher weekly resistance training volumes (up to 32 sets per muscle group per week) may elicit superior hypertrophic and strength gains compared to moderate volumes over an 8-week period.
Limits
The sample size was very small (9 participants per group), limiting statistical power. The study lasted only 8 weeks, leaving long-term sustainability and overtraining risk unassessed. The abstract does not report raw values, percentages, or exact effect sizes. Findings in resistance-trained men cannot be generalized to untrained individuals or females.