Acute and Long-term Responses to Different Rest Intervals in Low Load Resistance Training

Abstract

We investigated the effects of low load resistance training to failure performed with different rest intervals on acute hormonal responses and long-term muscle and strength gains. In the acute study, 14 participants were assigned to either a short rest (S, 30 s) or long rest (L, 150 s) protocol at 40% one-repetition maximum. Blood samples were taken before and after workout. Both groups showed significant (p<0.05) increases in growth hormone and insulin-like growth factor 1 immediately postworkout. In the longitudinal study, the same protocol as in the acute study was performed 2 times/week for 8 weeks by 21 volunteers. Both groups showed significant increases in triceps (S: 9.8±8.8%, L: 10.6±9.6%, p<0.05) and thigh (S: 5.7±4.7%, L: 8.3±6.4%, p<0.05) cross-sectional area. Onerepetition maximum also significantly increased for the bench press (S: 9.9±6.9%, L: 6.5±5.8%, p<0.05) and squat (S: 5.2±6.7%, L: 5.4±3.5%, p<0.05). In conclusion, our results suggest that acute hormonal responses, as well as chronic changes in muscle hypertrophy and strength in low load training to failure are independent of the rest interval length.