Physiological Implications of Two versus Three Sets in the Development of Quadriceps Muscle Strength in Untrained Men

Background: The purpose of this study was to determine if differences in strength gain are apparent following resistance training at two different exercise volumes (2-sets versus 3-sets). Methods: Seven men (age=21.6 ± 1.5) completed the study. Each subject trained one leg in the leg extension exercise using two sets and trained the other using three sets. Subjects were randomly assigned to two groups then treatments were randomly assigned to groups to minimize bias: one group assigned two sets right leg and three sets left leg (3L 2R; n = 3), one group assigned three sets right leg and two sets left leg (3R 2L; n=4). One repetition maximum (1RM) was determined for each leg of each participant for the leg extension prior to the three sessions per week and six week duration training program. Each set included in training consisted of six repetitions at a workload of 80% 1RM during each session. 1RM was tested after 2 and 4 weeks allowing for training workloads to be adjusted to 80% of current 1RM to apply the principle of progression. Results: Significant differences were apparent when comparing pre- and post-training absolute 1RM measures for both the two set and three set legs (p<0.05). There was a significant difference in magnitude of change between the two set and three set legs, 12.6 kg versus 19.4 kg respectively (p=0.02). Conclusion: While six weeks of either two or three sets of the leg extension exercise training both significantly increase quadriceps strength, the three set configuration creates a significantly larger magnitude of change compared to two sets.