ExerStats Manual 2017-08-19T11:23:38+00:00


 How can the ExerStats manual & Exercise chart help you?


  • The Exercise chart gives an overview of all the exercises Bret Contreras and I recommend for the Glutes, including classification into categories and exercise types.
  • The ExerStats manual pages show you how much an exercise activates (parts of) a muscle, which lets you target the muscles you want to grow.
  • The ExerStats manual pages let you calculate ActiMotion (more on this below), so you know how much growth-stimulating volume every muscle gets.
  • The ExerStats manual pages show you which other muscles an exercise activates. Knowing this allows you to manage the total ActiMotion a muscle gets from “overlapping” exercises, or to train around injuries to specific muscles.

To summarize, these resources help you to design the training program that’s perfect for your personal body shape goals and needs.

Just subscribe with your e-mail address, and you’ll get an e-mail to confirm the subscription. Afterwards, you’ll receive another e-mail with download links to the PDF files. (if you’re already part of the e-mail list and you would like to receive this manual, just e-mail [email protected] for the download link).

Of course, I will respect your inbox. I too hate spam mail. I too hate irrelevant mail. But I would love to keep you updated on further pages of the manual. If you don’t want this, just let me know and I’ll remove you from the mail list.


I urge you to read the following, as it clarifies a lot of what you’ll see in the manual pages:


Training for Body Shape

You are probably different from men in the way you train. That’s because you have different goals. This is especially true when it comes to body shape. While men’s body shape goals are often characterized by ‘more of every shape is better’, women’s body shape goals tend to be more subtle. Individualized. Specific.

Specific body shape goals call for a specific exercise selection. The ExerStats manual can help with that.

Training certain muscles to grow is key to get the body shape you want. However, information on which exercises precisely stimulate which muscles is hard to find, and often incorrect.

Remember that sticker on the smith machine that told you doing front squats trains your hamstrings? Science would not agree.

ExerStats: from studies to infographics

Scientific studies can tell us which exercise trains which muscle by measuring muscle activation through ElectroMyoGraphy (EMG). To do this, electrodes are placed on the skin to detect electrical signals going from the brain to the muscles during an exercise. Afterwards, a computer converts these to an EMG signal which you can see on a computer screen.


A bunch of studies (and experiments, thanks Bret Contreras) have used EMG in this way to see which exercises best activate certain muscles. I used these data to create the ExerStats infographics you can see on my Instagram profile.

I wanted to give this information to the people that actually need it. To you, so you can make optimal exercise choices for your training program, and achieve your body shape goals.

Muscle Activation and Range of Motion

ExerStats can precisely tell you which muscle each exercise activates, and which it doesn’t. Also, it tells you how much this muscle gets activated, on average, during the entire movement of the exercise. This is called Muscle Activation (mean activity in the ExerStats manual).


Why is muscle activation important? Well, muscle activation seems to be highly associated with muscle growth. [1, 2]

Also, muscle activation is related to the amount of tension in a muscle during exercise. Brad Schoenfeld, a renowned muscle growth specialists, argues that Muscle Tension is one of the major factors that affect muscle growth. [3]

The ExerStats (and ExerStats manual) also show how much a muscle moves while it’s activated. This is called Range of Motion (ROM). Studies show it’s another important factor for muscle growth. [4, 5]


So now we know that 2 things are important for muscle growth, namely Muscle Activation (which also relates to muscle tension) and Range of Motion.

Below is an example of a single ExerStats for the Lying Leg Curl. It shows both the mean activity and ROM.


A different way of calculating Training Volume

Let’s say you know how much an exercise activates a muscle. And how much that muscle is in motion while it’s activated. That can tell you something about how good the exercise is at stimulating muscle growth. This in turn helps you make proper exercise choices to grow certain muscles, and shape your body the way you want.

Traditionally, researchers have estimated how much total growth-stimulus a muscle gets by calculating the amount of training volume an exercise produces. [6, 7]

A method for calculating this is the ‘Weight-based Volume’ calculation. For example, compare doing half-reps on the Leg Press to the Full Squat.

  • half-rep Leg Press: 3 sets x 10 reps x 200 lbs. = 6000 lbs of volume.
  • Full Squat: 3 sets x 10 reps x 100 lbs. = 3000 lbs of volume.

Now some questions arise:
Don’t Full Squats also have you lift part of your own body weight? Where is this reflected in the calculation?
Which specific muscles of the legs does the training volume stimulate?
Are half-reps on the Leg Press indeed 2x better for leg muscle growth than Full Squats?

Our intuition says no. Our intuition is probably right.

Calculating training volume like this makes it look like the half-reps of Leg Press are superior.

A possible solution is taking the % of the 1-Rep Maximum (%1RM) instead of the lifted weight in lbs. This results in the following:

  • half-rep Leg Press: 3 sets x 10 reps x 70%1RM = 2100 of volume.
  • Full Squat: 3 sets x 10 reps x 70%1RM = 2100 of volume.

This calculation gives the same Training Volume for both exercises. That’s better. But it still doesn’t show which specific muscle gets the stimulation.

This is where a new way of calculating volume can help: ActiMotion.

ActiMotion combines 2 important factors for muscle growth, Mean Activity and Range of Motion, to calculate how much an exercise stimulates a specific muscle to grow.

Also, it takes into account the the muscle specificity of the exercise. These are all things the previous 2 methods for calculating training volume neglect.

The calculation looks like this:


Let’s look at which exercise ActiMotion judges to be better for leg growth by looking at the quadriceps (front upper leg muscle).

  • half-rep Leg press: 3 sets x 10 reps x 93% x 0.44 = 1228
    because: Leg Press activates the quadriceps for 93% of the Hack Squat (which shows most quadriceps activity of all exercises) and the range of motion of the quads during the exercise is 75° / 170° (maximum when stretched).
  • Full squats: 3 sets x 10 reps x 83% x 0.68 = 1611
    because: Full Squats activate the quadriceps for 83% of the Hack Squat (which shows most quadriceps activity of all exercises) and the range of motion of the quads during the exercise is 110° / 170° (maximum when stretched).

That makes more sense! Sure, the quads don’t get activated as much during the Full Squats as during the half-rep Leg Presses, but the Range of Motion is greater. This results in more growth stimulus from the Full Squats.

Below you can see the 3 methods of training volume calculation and their results:


Finally, ActiMotion can uncover which muscles might get a little too much volume. Knowing this will help in preventing overtraining by keeping Stimulus and Recovery properly balanced.



1. Wakahara, T., Miyamoto, N., Sugisaki, N., Murata, K., Kanehisa, H., Kawakami, Y., … Yanai, T. (2012). Association between regional differences in muscle activation in one session of resistance exercise and in muscle hypertrophy after resistance training. European journal of applied physiology, 112(4), 1569–76.

2. Wakahara, T., Fukutani, A., Kawakami, Y., & Yanai, T. (2013). Nonuniform muscle hypertrophy: Its relation to muscle activation in training session. Medicine and Science in Sports and Exercise, 45(11), 2158–2165.

3. Schoenfeld, B. J. (2010). The mechanisms of muscle hypertrophy and their application to resistance training. The Journal of Strength & Conditioning Research, 24(10), 2857-2872.

4. McMahon, G. E., Morse, C. I., Burden, A., Winwood, K., & Onambélé, G. L. (2014). Impact of range of motion during ecologically valid resistance training protocols on muscle size, subcutaneous fat, and strength. Journal of Strength and Conditioning Research / National Strength & Conditioning Association, 28(April), 245–55.

5. Pinto, R. S., Gomes, N., Radaelli, R., Botton, C. E., Brown, L. E., & Bottaro, M. (2012). Effect of range of motion on muscle strength and thickness. The Journal of Strength & Conditioning Research, 26(8), 2140-2145.

6. Krieger, J. W. (2010). Single vs. multiple sets of resistance exercise for muscle hypertrophy: a meta-analysis. The Journal of Strength & Conditioning Research, 24(4), 1150-1159.

7. Fisher, J., Steele, J., Bruce-Low, S., & Smith, D. (2011). Evidence-Based Resistance Training Recommendations for Muscular Hypertrophy. Medicina Sportiva, 17(4), 217–235.