If you’ve just started doing strength training and are short of time, then Brazilian sports scientists at the University of Brasilia have good news for you. The amount of time you rest between sets does not affect your progress. So strength training doesn’t have to take much time.
The researchers got 34 male students, all new to weight training, to train their most important muscle groups for a period of 12 weeks. Twice a week the test subjects did 5 basic exercises for their major muscle groups, including dead lifts, bench presses and leg presses. Half of the group took just over one minute rest between sets [SR]; the other half rested for three minutes [LR]. The SR group made 14.4 percent progress, the LR group 10.5 percent. The difference in progression between the two groups was not statistically significant.
The graph below shows the progress in strength that the test subjects made on the leg press. For this machine both groups showed almost the same progression: The 1RM for the SR group increased by 17.5 percent and for LR group by 17.8 percent.
In their conclusion the researchers emphasise that they only looked at strength. “It is important to note that the results are limited to muscle strength, and the manipulation of rest intervals may interfere with other adaptations such as muscle hypertrophy and endurance.”
Chronic effects of different between-set rest durations on muscle strength in nonresistance trained young men.
The purpose of the study was to investigate the effects of different between-set rest interval durations on muscle strength after 12 weeks of resistance training. After baseline tests, 34 nonresistance trained college-aged men were matched and randomly assigned to 2 groups. Both groups trained twice a week and performed the same exercises and the same work output with 2 sets of 8 to 12 repetitions until volitional fatigue. One group (n = 18, 21.4 +/- 3.2 yr; 73.8 +/- 14.0 kg; 175.9 +/- 7.8 cm) used short-rest intervals (SR) with a work rest ratio of approximately 1:3; the other (n = 16, 22.4 +/- 2.6 yr; 73.1 +/- 13.6 kg; 171.9 +/- 8.2 cm) used long-rest intervals (LR) with a work rest ratio of approximately 1:6. Leg press and bench press 1 repetition maximum (1RM) were measured at baseline and after the end of the training period. The increases in 1RM for bench press were 14.4 +/- 8.1% for the SR group and 10.5 +/- 6.4% for the LR group (p < 0.05). For the leg press, the increases were 17.5 +/- 9.2% with SR training and 17.8 +/- 12.3% for the LR group (p < 0.05). The results did not reveal significant differences between SR and LR for the bench press or leg press 1RM (p > 0.05). Our data suggest that gains in maximum strength in nontrained men are not dependent on the length of the rest interval between sets. Therefore, personal trainers and strength coaches can advise beginning lifters to use short rest intervals to make best use of their time in the weight room.
PMID: 19966591 [PubMed – indexed for MEDLINE]