Strength increases in upper and lower body are larger with longer inter-set rest intervals in trained men

The purpose of the current study was to compare different rest interval durations on upper and lower body strength. Thirty-six recreationally trained men were randomly assigned to 1 min (G1; n = 12), 3 min (G3; n = 12) or 5 min (G5; n = 12) rest interval groups. Each group performed the same resistance training program. Maximal strength was assessed at baseline, mid-point (8 weeks) and post-training (16 weeks) for the bench press and leg press exercises. For the bench press, significant increases were demonstrated within G3 and G5 at 8 weeks and at 16 weeks versus baseline (p < 0.05). Additionally, for the bench press, G5 (98.2 ± 3.7 kg) was significantly stronger than G1 (92.5 ± 3.8 kg) at 16 weeks (p < 0.05). For the leg press, significant increases were demonstrated within all groups at 8 weeks and at 16 weeks versus baseline (p < 0.05). Additionally, for the leg press, G5 (290.8 ± 23.5 kg) was significantly stronger than G1 (251.0 ± 15.8 kg) at 8 weeks (p < 0.01) and G3 (305.0 ± 23.9 kg) and G5 (321.7 ± 21.7 kg) were significantly stronger than G1 (276.7 ± 10.7 kg) at 16 weeks (p < 0.05). The findings of the current study indicate that utilising 3 or 5 min rest intervals between sets may result in significantly greater increases in upper and lower body strength beyond the initial weeks of training versus utilising 1-min rest intervals between sets.