You’ve started your resistance training routine, but you’re unsure how long to wait between each set. The answer to this is dependent upon the results you’re seeking. If you are trying to lose weight then you should aim for muscle endurance and, eventually hypertrophy (enlargement of skeletal muscle fibers to overcoming force from high volumes of tension). I recommend hypertrophy because muscle burns more calories, therefore the more lean muscle you build, the more calories you are burning throughout the day. With a goal of muscle gain, you should aim for hypertrophy and maximal strength training. If your goal is to improve general sports performance then you should aim for power training. Now that you know what type of training you will be doing, you can determine how long you should rest between sets.
According to the National Academy of Sports Medicine, your rest intervals should be applied as follows:
- Muscular endurance and stabilization: 0-90 seconds.
- Hypertrophy: 0-60 seconds.
- Maximal Strength: 3-5 minutes.
- Power: 3-5 minutes.
Now for the science behind these numbers. Adenosine Triphosphate (ATP) and phosphocreatine (PC) are what fuel the majority of a resistance workout. Replenishing these supplies is necessary for optimal performance and desired adaptations. Adjusting the rest interval allows energy supplies to be regained according to your training goals. Rest intervals of:
- 20 to 30 seconds will allow approximately 50% recovery of ATP and PC.
- 40 seconds will allow approximately 75% recovery of ATP and PC.
- 60 seconds will allow approximately 85 to 90% recovery of ATP and PC.
- 3 minutes will allow approximately 100% recovery of ATP and PC.
Be sure to use longer rest periods if you are new to exercise to ensure correct form and energy levels for your desired goals. If rest periods are too short for those new to exercise, fatigue will result. On the flip side, if rest periods are too long, decreased neuromuscular activity and decreased body temperature result. If a beginner then performs an intense bout of exercise, injury could result. Remember to ease your way into training, and figure out what your goals are before you begin.