As a personal trainer, customers often ask me, “How much time should I rest between sets?”
My answer always depends on the customer’s goal. I have trained clients to train absolute strength, aesthetics, weight loss, and / or improving muscle endurance. Your workouts (or at least some of them) required different rest intervals.
In their book, “Fundamentals of Strength Training and Conditioning,” the National Strength & Conditioning Association recommends the following:
- To increase strength and strength, the best rest time between sets is 2-5 minutes.
- To increase hypertrophy (muscle growth), the best rest time between sets is 30-90 seconds.
- To increase muscle endurance, the best rest time between sets is 30 seconds or less.
These rest periods are based on how the body produces the energy to do work during exercise. In particular, the body uses three different energy systems at any one time; However, the amount of contribution each energy system makes depends on the intensity and duration of the event.
Which energy systems drive your training?
The phosphagen system
For strength activities like One-Rep-Max (1
A phosphagen is an energy-storing compound like creatine phosphate or ATP. Phosphagens are used up during intense exercise such as weight lifting and sprinting. The complete ATP resynthesis takes place within 3-5 minutes – hence the indication that strength and performance athletes rest for such a long time between sets.
Building more muscle can lead to more phosphagens, allowing leaner individuals to experience higher intensity or longer duration of the previous intensity.
The glycolytic system
Work for more than 30 seconds and up to 2 minutes and you are using the glycolytic energy system. It involves breaking down glycogen, which is stored in glucose, or glucose in the blood, to re-synthesize ATP.
There are roughly 300-400 grams of glycogen in the muscle of the body and 70-100 grams in the liver, but these numbers can be increased through weight training, aerobic exercise, and a nutritious diet. If you exercise very hard – say, at 100 percent of your maximum oxygen intake or VO2 max – you can burn out all of the glycogen stores in some muscles. To replenish these supplies, consume plenty of carbohydrates every two hours after a hard workout. You can get a full refill within 24 hours.
Bodybuilders typically train with a range of repetitions and at an intensity that involves the phosphagen and glycolysis systems. With 8-12 reps at 60-85 percent of 1 RPM, bodybuilders try to break down their glycogen, stimulate growth, and instantly re-feed their muscles.
This is also why people ingest branch-chain amino acids during exercise – in the event that all of the glycogen has been depleted through multiple training sessions and the body begins to use amino acids for energy.
Adding extra amino acids to the protein pool can keep some of the body’s natural amino acids from being broken down. In the case of ketogenic trainees, their abundance of fat stores will be depleted before their bodies start using protein.
The oxidative system
After 2-3 minutes of work you are still using the glycolysis system but invoking more oxidative or aerobic systems. The oxidative system uses carbohydrates, fats and, as a last resort, protein for energy.
Muscle cardio training can include sets that last 2-3 minutes; For example, a set of 30 bodyweight squats or lunges can take 2 minutes. Three sets of 20 to 30 repetitions of an exercise will target both the glycolysis and oxidation systems. During muscle endurance training with weights or body weight only, rest 30 seconds or less between sets.
Activities that last longer than 3 minutes, such as B. a 1 mile run, primarily use the oxidative system. When doing such low intensity exercise, you need to make sure your electrolytes, hydration, and food intake are on the right track as it is a race against time before you get completely tired. During long, stationary, low-intensity cardio workouts, rest periods are usually taken as needed.
Interval training includes a training intensity close to VO2 max. It is usually used for aerobic cardio training with activities like running, cycling, climbing stairs, and swimming. Use working hours of 3-5 minutes and rest afterwards.
The work to rest ratio during interval training should be 1-1, which means you rest as much as you work. Interval training should increase VO2 max and improve power generation.
High intensity interval training
High-intensity interval training (HIIT) involves repetitive hard work steps, interrupted by short rest periods. Here, too, you train close to your maximum heart rate or VO2 max. You can even exceed these limits for a few seconds.
The HIIT workout can be short (less than 45 seconds of work) or long (2-4 minutes). I like to start with shorter workouts with a 1-1 or 1-2 work-to-rest ratio. I usually add 30-60 seconds on top of the rest interval between laps for rest time between laps.
In this example, the phosphagen system cannot handle the load, and the glycolytic and aerobic energy systems come into play. Even so, 1 minute and 40 seconds is enough for the body to replenish some phosphagens so that the phosphagen system is used at the beginning of each round. Eventually, however, the body needs to break down glucose for energy.
Strength and muscle regeneration research
In general, recent research on the impact of rest interval length on strength and muscle recovery suggests that more rest is better.
A 2017 study looked at muscle fatigue after three different CrossFit workouts: “Cindy” (as many rounds as possible of 5 push-ups, 10 pull-ups, and 15 squats in 20 minutes); a HIIT jump rope “double under” workout that required 8 rounds of 20 seconds of work and 10 seconds of rest; and a weightlifting workout that consists of as many reps as possible of a barbell power clean, done at 40 percent of 1 rpm in 5 minutes. The only training with rest intervals was the jump rope training.
Before, during and 3 minutes after each training session, the subjects were tested for their jump height. The result was that, in contrast to the other no-rest groups, the double-under subjects were able to regain their jumping ability 3 minutes after training. The restored jumping ability was likely explained by the restored creatine phosphate levels. The short duration of the training and the short rest periods enabled the body to gain more energy.
According to a 2015 study, a 2-minute break is more beneficial than a 1-minute break for maintaining power delivery across sets. In this case, participants did 6 sets of 6 repetitions of Smith machine squats at 60 percent of 1 rpm, with rest for either 1, 2, or 3 minutes between sets. Although the power output decreased during exercise, there was a smaller decrease in average power when they rested for 2 minutes compared to when they rested for 1 minute (2.6 percent versus 10.5 percent).
There are numerous other studies of rest intervals in weightlifting, and the general trend is that more rest means better results.
Use a watch with a vibrating timer, your mobile phone, or the nearest watch to keep track of your rest times. There are also some good interval training apps that you can use to create custom work and rest times.
- Haff, G. & Triplett, NT (2016). Basics of strength training and conditioning, 4th ed. National Strength and Conditioning Association.
- Maté-Munoz, JL, et al. (2017) Muscle Fatigue in Response to Different Modalities of CrossFit Sessions. PLOS One, Dec.(7), e0181855
- Martorelli, A., et al. (2015). Neuromuscular and blood lactate responses to squat strength training with varying rest intervals between sets. Journal of Sports Science and Medicine, 14(2), 269- 75.