Resistance training for strength and muscle thickness: Effect of number of sets and muscle group trained

Objectives. - To investigate the effects of resistance training volume on the adaptations of different muscle groups in untrained young men. Equipments and methods. - The volunteers were randomly assigned into two groups: (1) three sets of knee extension and a single set of elbow flexion (3K-1E; n = 11), or (2) single set of knee extension and three sets of elbow flexion (1K-3E; n = 13). Subjects trained two days per week for 12 weeks. Peak torque (PT) was measured at 60 = s(-1). Muscle thickness (MT) was measured by ultrasound. Results. - Elbow flexors' MT increased significantly for both groups (7.2% for 3K-1E and 5.9% for 1K-3E), while changes in quadriceps' MT were not significant for either group (2.5% for 3K-1E and 2.9% for 1K-3E). Increases in elbow flexors' PT were 11.2% for 3K-1E and 12.5% for 1K-3E (P < 0.05 for both). Changes in knee extensors' PT were significant for 3K-1E (10.9%, P < 0.05) but not for 1K-3E (5.1%, P > 0.05). Conclusion. - Single-set training protocols might be sufficient for increasing strength and MT of the elbow flexors and muscle strength of the knee extensors in untrained individuals. On the other hand, neither training stimulus (one set nor three sets) was sufficient to improve the MT of the knee extensors. (C) 2010 Elsevier Masson SAS. All rights reserved.