It’s no secret that rest is an essential part of the training process.
Rest too long and you won’t see the results you’re looking for.
Skip rest altogether and you’re setting yourself up for failure real fast.
So, how long should you rest between sets? Is there a magic amount of time that’s best for muscle growth?
The answer is actually more complicated than you think.
3 main energy systems
To understand why you need rest, you should first understand the science behind the systems in your body that allow you to have the energy to push through a workout.
The three systems below help you to continue with your workout. If one of them fails, you are going to fail. Got it? Good.
Here they are and how they work:
This system is responsible for the provision of ATP (adenosine triphosphate) from creatine.
Both of these compounds help the body during intense muscular activity for a short duration.
This diagram shows how the phosphagen system creates energy for the muscles to use.
The phosphagen energy system releases energy for immediate use but is also only available for a short amount of time, around the first 10-30 seconds of activity.
This system is often used for short but intense movements like weight lifting, jumping, throwing, hitting, or sprinting.
After the phosphagen system has run out of energy, the glycolysis system kicks in. the glycolysis system breaks down glycogen to be used for energy.
This diagram shows how the glycolysis system creates energy for the body to use.
This system takes over and continues to create ATP for energy for up to 2 minutes. This system is also known as the anaerobic system.
When the first two systems have been depleted of energy, your body then relies on the oxidative, or aerobic system.
This is your endurance energy system and it relies on all the energy stored in your body including your carbohydrates, fats, and protein.
Most people who are trying to gain mass and strength, don’t want to reach this point until they are training for muscular endurance.
Goals and training types
Now that you understand the three different systems that provide energy at different stages of exercise, you better understand why rest is so important.
If you want to make sure you don’t deplete a certain system, you need to ensure that you rest enough to give the needed energy system time to replenish.
Power and strength training
For this type of training, the goal is to gain strength and muscle. In order to do that you need to lift heavy with for fewer reps.
The type of energy system that provides the most benefit for this training is the phosphagen energy system.
This system drains of energy fast, giving you only about 10 seconds of maximum output.
It does, however, also replenish relatively fast.
According to ScienceDirect, the phosphagen energy levels can replenish 70% of the way in 30 seconds but needs 3-5 minutes to replenish completely.
So, how does this translate into terms of maximum results for strength training?
The longer you rest up to 5 minutes, the more ATP you will have to supply your muscle with energy and the heavier you will be able to lift once more.
Give this system too short of a recovery time and you won’t have the necessary muscle energy to lift your heaviest with the most reps.
When it comes to gains, speed is not the pivotal factor – volume is.
To reiterate, when training for strength, the best rest between sets is 3-5 minutes.
Bodybuilding and hypertrophy training
To increase your muscle mass and get those longed for “pumps”, the resting period should be a tad shorter than for strength training.
Since hypertrophy training lowers the weight lifted and adds more reps to each set, it uses more of the glycolysis system for its energy.
You will have drained your phosphagen energy and tapped into your stored carbs, or glycogen, for fuel.
When it comes to hypertrophy training rest periods, you have two schools of thought.
One group swears that a 1 minutes resting period between sets is the best.
It causes the body to release more growth hormones and causes blood flow to the worked muscles, delivering oxygen and nitrogen giving you that “pump” look.
This is short-lived, however, and after the initial swelling of the muscles, they go down and you won’t see as much growth.
The other group of people sticks with the resting period similar to strength training: 2 to 3 minutes for the compound movements. Why?
Even with the added release of growth hormone in shorter rest periods, longer rest periods allow your energy systems to replenish to 100%. And remember what that allows you to do?
With all your muscle energy available, you can lift more total volume in your workout. More volume still beats growth hormone with lighter lifts.
This study proved the second school of thought to be the lucky winners.
Volume is still king when it comes to strength and growth.
With isolation movements though the rest periods should be between 30 to 90 seconds as you don’t get as many muscle groups involved during the set so you can recover faster.
When lifting for endurance, you want your muscles to train to last longer.
This means you will be lifting lighter weights than normal and going through lots of reps and sets.
You will have run through your phosphagen system, you will be close to using up your glycogen and you will now have the backup of the oxidative system or aerobic system.
The point of this type of training is to make your muscles less prone to fatigue.
In order to do this, you want your rest periods to be shorter, forcing your body to get more efficient at clearing away lactic acid.
To increase your lactic threshold, or how much burn your muscles can undergo, you should rest about as long as you worked. This is a 1:1 ratio.
If you do 16-20 reps of any lift with medium weight, it will take you about 45 seconds to a minute. Therefore, you should rest between 45 seconds to a minute.
To reiterate, you should have a 1:1 work to rest ratio when endurance training.
For best results, you want to find that sweet spot that works for you when it comes to rest periods between sets.
Too short of a rest won’t give you enough time to replenish your energy levels for maximum volume and too long will allow your muscles to cool down and will set you up for injury.
Play around with the numbers within the guidelines above and find out what works best for you. Pay attention to your body, your max lifts, and your form.
A good number will allow plenty of muscular energy for the highest lifts with good form in the shortest amount of time.