The correct planning of a strength training program involves the manipulation of variables such as the selection and order of exercise execution, volume, frequency and intensity of the training, speed of movement, and the rest between sets. Volume (number of sets and repetitions) and intensity have received the most significant attention over the years since they are the ones that have traditionally been best related to strength and muscle hypertrophy. However, rests between sets, often ignored, can play a crucial role in our goal. The duration of this rest should be sufficient to allow the replacement of ATP and phosphocreatine and the elimination of the accumulated lactate. Despite its importance, the ideal duration of the rest interval between sets and exercises is not fully established for strength training.

How long should we rest between series?

This is one of the big questions that anyone interested in strength is likely to ask themselves since it is one of the most critical aspects of achieving the desired adaptations. One of the main difficulties we find when determining the optimal recovery period between sets is that the time required for complete recovery will depend on many other factors. For example:

• the training’s intensity,
• load’s magnitude,
• gender,
• age,
• level of experience of the individual,
• type of fibre and
• genetics will influence the choice of the rest interval. ^1–4

The evidence that has emerged in recent years has shown that different rest times between series can produce different acute responses and chronic adaptations. The American College of Sports Medicine -a leading institution in exercise and health-in its strength training guidelines for adults recommended using rest periods of at least 2–3 minutes for activities that involve the greatest loads, regardless of the person’s previous level of strength training experience. ⁵  For the rest of the exercises, it stated that a shorter rest period, 1–2 minutes, could be sufficient. ⁵  When it comes to chronic adaptations, a review of 35 studies published in the prestigious Sports Medicine magazine concluded that rest periods of 3–5 minutes produce the most significant gains in strength. ⁶ 

More recently, a systematic review attempted to determine the optimal rest between sets and exercises to maximise the adaptations achieved through strength training. ⁷  The analysis of 23 studies which included 491 people, established that trained people achieved the most significant increases with rests above 2 minutes. However, short periods of rest (<60 seconds) promote improvements in strength. In the case of those with no previous experience in this type of training, it seems that breaks of between 60–120 seconds are sufficient to achieve improvements in strength. ⁷ 

One of the main reasons would be that more extended rest periods allow a greater volume of training (greater number of repetitions), ^8.9, and maximise strength gains. In this context, the pause-rest method (or rest-pause training) has recently been proposed (among other training techniques such as descending series or drop-sets and supersets) to increase the training volume more efficiently. In other words, they were using less training time. ¹⁰  The rest-pause method consists of dividing a given number of total repetitions of a series into several mini-series, with the proper rest between each of them to maintain the load. However, the results of a study on this method’s longitudinal effects (a set up to failure at 80% of 1-MRI with a rest interval of 20 seconds between mini-series until completing a total of 18 repetitions) revealed that the strength increase was similar when compared to a traditional training programme (3 sets of 6 repetitions at 80% of 1-MRI, with 2 minutes of rest between sets). ¹¹  Of course, while the total time invested in completing a session was 57 minutes for the traditional training group, in the pause-rest method, it was 35 minutes. ¹¹

Conclusions

Although the ideal recovery time seems to depend on many factors that mean that, today, the optimal rest period between sets and exercise is unknown, it does seem clear that long rest intervals (above 2 minutes) are recommended for maximizing strength gains. In addition, inadequate rest can lead to significant side effects such as increased fatigue. Since these workouts focused on developing strength are very intense, looking in many cases for muscle failure will cause that, if we do not recover properly, the possibility of injury will increase. Finally, exercise professionals must always pay attention to these studies to objectively know which strategies are the most effective to achieve their objective, but always prioritizing the principle of individualization of training, given the variability of the responses that occur among different people.

References:

1. Suchomel TJ, et al. The Importance of Muscular Strength: Training Considerations. Sports Med. 48, 765–785 (2018).
2. Ratamess NA, et al. The effects of rest interval length on acute bench press performance: the influence of gender and muscle strength. J. Strength Cond. Res. 26, 1817–1826 (2012).
3. Willardson JM. A brief review: factors affecting the length of the rest interval between resistance exercise sets. J. Strength Cond. Res. 20, 978–984 (2006).
4. Tibana RA, et al. Higher muscle performance in adolescents compared with adults after a resistance training session with different rest intervals. J. Strength Cond. Res. 26, 1027–1032 (2012).
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