The length of a rest period between training sets is one of the most neglected aspects of muscle building, which is understandable since there’s already so much to think about in terms of exercises, nutrition and supplementation. However, science has repeatedly suggested that the length of the rest periods is one of the key contributing factors for achieving muscle hypertrophy during a workout and by simply making smarter decisions about the duration of rest between sets, we could reap even better gains from a well-crafted workout.
More specifically, studies in the past have offered evidence that short rest periods cause potent boost in the production of anabolic hormones such as growth hormone and testosterone, while they also increase the level of metabolic stress in the muscles, which is thought to be one of the most influent mechanisms of hypertrophy. But more recent efforts have questioned these claims. For example, short rest periods also increase fatigue and can significantly limit the number of reps that could be performed, thereby diminishing the effectiveness of the workout.
In the hope of clearing up the confusion, a group of researchers from the University of Birmingham conducted a study comparing the effects of short and long rest periods on athletic performance. The subjects, 16 male lifters, were divided in two groups and were told to perform four sets of leg presses and four sets of leg extensions, with rest periods of one minute for the first group and five minutes for the second group. After the workout, both groups drank whey protein. Then, the activity of anabolic pathways was measured through muscle biopsies, while the rates of protein synthesis were assessed with the help of infusion of radiolabeled phenylalanine.
The results showed that the five-minute rest group had a much greater rate of muscle protein synthesis in the first four hours after training, while a certain level of anabolic pathways reduction was determined in the one-minute rest group. Additionally, it was found that the one-minute rest group had increased activity of some pathways which have the ability to *blunt* the anabolic pathways. However, in the next 28 hours after the workout, both groups experienced similar lasting elevations in muscle protein synthesis rates without any significant differences. Furthermore, at the 40-minutes post-exercise mark, testosterone production was higher in the one-minute rest group, compared to the five-minute group.
These findings suggest that rest periods of one minute between sets *blunts* muscle protein synthesis in the short term and rest periods of five minutes are more effective when it comes to stimulating optimal levels of muscle hypertrophy and growth. However, the long-term effects of this process on bodybuilding gains is still to be investigated in future research. At the end, the data concerning the ideal rest length remains contradictory, most likely because of the effects of muscle adaption. But based on what we already know, it’s safe to conclude that both strategies have their own unique set of advantages and flaws, so it’s up to you to determine which one works better for your personal goals. In the long term, it shouldn’t matter whether you use short or long rest periods. However, if total volume is an important aspect of your current training regime, make sure to use longer rest periods because they have a better ability to help you achieve your target volume, while short rest periods will lead to a much faster muscle exhaustion.