How to Maximize Muscle Growth using Rest Periods

Ever since Arnold was pumping iron until the late 2000s bodybuilders and coaches believed that short rest periods maximize muscle growth.

At the time, researchers were convinced that the spike of growth hormone and testosterone produced by lifting weights were the main causes of muscle growth. As a result most training programs were designed around this belief.

Compound movements, 10-12 reps per set and short rest periods.

This is what creates the largest spikes in hormones so this was believed to be the ideal formula for gaining size. Almost everyone used and preached that type of training. Even research as recent as 2006 recommended rest times of 30-60 seconds for the goal of muscle growth.

But that turned out to be wrong. We now know that full rest periods (2-4 minutes between sets) are actually superior for both strength and muscle growth.

Why short rest periods don’t maximize muscle growth

Growth hormone. It makes you think of getting bigger right?

Well apparently, growth hormone is released in response to stress, such as strength training but it doesn’t cause muscle growth. Even when taken at supra-physiological levels by bodybuilders, it still doesn’t produce hypertrophy. This is the main reason the hormone hypothesis was dropped. People used to restrict rest time for the purpose of increasing growth hormone but if it doesn’t produce muscle growth then what’s the point?

The spike in testosterone after training was also believed to be causative of muscle hypertrophy. There’s no denying that high doses of testosterone leads to muscle growth. Hell, steroids build muscle even without training.

But slightly raising testosterone for a few hours by lifting weights doesn’t even compare to taking steroids. Research has shown that manipulating hormones in the natural, physiological range only has a small effect on muscle growth. Naturally, you can’t raise hormones enough to make a difference. You need testosterone at supra-physiological levels.

Short rest periods for Muscle Damage and Metabolic Fatigue

If you’re familiar with the recent research on muscle growth you know there are three primary ways to stimulate hypertrophy through training:

1. Progressive tension overload
   Lifting heavier and heavier weights over time
2. Muscle damage
   Creating microtears in the muscle fibers which neccesitate repair
3. Metabolic fatigue
   Pushing muscles to their metabolic limit (when you feel the burn)

Out of the three, the most important one is progressive overload – getting stronger – lifting heavier weights over time or performing more reps.

It is true that short rest periods increase muscle damage and metabolic fatigue. But if that comes at the expense of making slower strength gains you are actually training suboptimally. You are compromising the primary driver of growth.

It is well established that using very short rest intervals can reduce the number of repetitions that can be performed on subsequent sets [17]. Thus, if you restrict rest periods for the purpose of increasing metabolic fatigue to the point where you perform less total repetitions, or have to use lighter loads on subsequent sets, you are essentially “throwing the baby out with the bathwater”. Meaning, you have sacrificed total volume for metabolic fatigue.  – Eric Helms

You want to start each set well recovered so that you can lift at your maximum potential.

How long to rest between sets

• For compound movements (bench press, rows, squats, etc) – rest 2-3 minutes between sets. Sometimes when you’re feeling really beat up you can take 4 minutes of rest
• For accessory movements (curls, extensions, machine exercises, etc) – rest 1-2 minutes between sets

Some people will say 4 minutes of rest between sets is much too long to be optimal.

The fact of the matter is no study has ever shown long rest periods to affect muscle growth. All the studies either showed no difference between groups or actually showed longer rest periods to be superior. For example in a recent study conducted by Dr Brad Schoenfeld, the group that rested 3 minutes between sets gained more muscle mass and strength compared to those resting just 1 minute.

The Value of Rest Pause training

But short rest periods do have a place in a good training program. Rest-pause training, intervals, supersets, circuit training they are all useful in certain situations.

Rest-Pause training is particularly effective. In the Superhero Bulking Program, Greg explains it like this:

One of the primary reasons why lifting heavy and taking long rest periods is the most effective way to  build muscle is because it results in a high level of muscle fiber recruitment. So if you’re lifting at your absolute 5-8-rep max, you’re likely using a near maximum amount of your muscle fibers for each and every rep.

When you’re training with lighter weights and performing higher reps, you only come close to full muscle fiber recruitment on those last really tough reps. Therefore you have to do several sets with a lightweight to trigger adequate muscle gains. For example, if you did 5 sets of 10 reps with 60 seconds rest then you’ve done 50 reps total, but probably only 15 of those reps really counted. Fortunately for us, there’s a loophole to get full muscle fiber recruitment with lightweight pump training. The answer my friend is rest pause training.

The premise of rest pause training is simple. You want to pick a weight you can do for 12-15 reps before hitting complete muscle failure. This is your activation set. During the last few really tough reps of the movement, you’ll start to use maximum muscle fiber recruitment. It’s only when you’re using the maximum number of muscle fibers, that you’re able to trigger the most amount of muscle growth. After you finish your activation set, you’ll maintain this state for up to 20-30 seconds or so. Meaning that if you
take a short 15-20 second break and then pump out a few more reps, you’ll still be using maximum muscle fiber recruitment. If you do 4 of these mini sets, you’ll be getting the same benefit as if you did 5 full sets, but with much less work and in much less time. This allows you to get rid of all of the unessential and train with greater and more focused intensity.

For the muscle groups that can’t be trained effectively with heavy weights taking very short rest periods can simulate heavy training. Greg and I use this style of training for lateral and rear delts and sometimes for arms. But Børge Fagerli who invented this training system, explains how you can use it for compound movements as well.

Conclusion

• Full rest periods (2-3 minutes) are superior for strength and muscle gains because they allow you to accumulate more heavy volume (you don’t lose reps because of fatigue).
• Short rest periods (1-2 minutes) can be used for accessory movements because smaller muscle groups recover faster (you don’t lose reps because of fatigue).
• Very short rest periods can be used in some training styles such as Rest-Pause Training (you still accumulate efficient volume this way).

Before we wrap up I want to give a huge shout-out to Eric Helms. This post is based on the chapter on rest periods from his book the Muscle and Strength Training Pyramid. I highly recommend you check it out.

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The Greek God Program

This is the training program I used to build my physique. It’s based around building strength on a few key exercises that will give you the look of a Hollywood actor.

Because you use Reverse Pyramid Training on compound movements you take long rest periods of 2-3 minutes between sets. This allows you go in every set almost fully recovered.

Learn more about the program here