A firm butt, a juicy booty, a round butt, godly glutes, a cherry bottom…

 Whatever you want to call it, you know what it looks like.
But what gets a booty so juicy? What makes a butt so firm?

1 word: size.

Muscle size, to be precise. Underneath that cushion of fat there are undeniably some slaps of butt muscle: the glutes.

The main glute muscles are the Gluteus Maximus and the Gluteus Medius, shown in the picture below.


As you can see, the Gluteus Maximus is a lot bigger than the Gluteus Medius. Even better: the Gluteus Maximus is the biggest muscle in the entire body! 

Hence, you can’t argue with the fact that the remainder of this article will focus on the Gluteus Maximus. From here, I will refer to this specific muscle as the ‘the glutes’.

Note: when you move your mouse over (or: tap your finger on) the sentences that are bold, you will see the scientific citation that supports it.


What gets glutes bigger?

Weight training! You have to stimulate a muscle in order for it to grow. Now that brings us to the key question of this article: what exercise is best at doing this?


Muscle activity causes muscle growth

The degree of muscle activation during an exercise is a good indicator for growth of that specific muscle[Wak’13Dic’10] Because of this, we have to look at which exercise shows the most activity for the glutes.

How is muscle activity measured?

Tons of studies have been conducted on muscle activition during exercises. Muscle activity is measured by sensing the electric currents that go from the nervous system to the muscle fibers. This sensing is done by electrodes that are placed on the skin at the location of the muscle belly. See the picture below.


‘Muscle activity’ refers to the mean activation that is registered during the entire movement of the exercise (the Goblet Squat, in this case).


Before we go on, I’d like to make the distinction between the upper glutes and the lower glutes. Every exercise activates these parts differently. 

The degree of activity of the upper/lower glutes decides whether this specific part will grow bigger or not[Wak’12]



The range of motion is also important

Not only muscle activation, but also the muscle length over which that activation occurs is important to muscle growth. [McMah’14] This is also called the Range of Motion (ROM) for this muscle.

You wanna have that juicy booty? Choose exercises that show high mean activation AND a big ROM!

Next, I will sum up what some well-known exercises do for your glutes using ExerStats.

Here comes the kicker: the ExerStats are ALL based on scientific research or muscle-activity experiments.


ExerStats Barbell Squat


The real-time activation is based on this video material of Bret Contreras.

Exerstats-BB-SquatBased on source [Con’15] and source [Ham’07] and source [McAl’14] and [Cla’12]

Explanation ExerStats:

 The ExerStats should be understood as follows: mean activity is shown for every muscle over the course of its ROM during the exercise. I have calculated these relative to the exercise that shows the highest activity possible for that specific muscle.

For example:
Barbell Squats show 83% of the activity of Hack Squats (highest possible) for the quads. So, indeed, the Hack Squat is probably a better exercise for that specific muscle group.
HOWEVER, the Barbell Squat still outperforms the Hack Squat at activating the lower back, the hamstrings, and the glutes. It’s a much better-rounded exercise.

Furthermore, the ROM for every relevant muscle is shown in the gauge.

 In the animation of the Barbell Squat, shown above, I included the ‘live’ activity in yellow. As you can see, the peak activity of the Squat can be way above the mean activity of the best exercise for the lower glutes, the American Hip Thrust.

Watch out mobile device users: the ExerStats are 0.5 MB each.

ExerStats Barbell Hip Thrust


Based on source [Con’15] and source [McAl’14]

ExerStats Bent Leg Glute Kickback


ExerStats_bent_leg_glute_kickBased on source [SuppVersity] and source [exper]

ExerStats Lunge


ExerStats_LungeBased on source [Ebb’09] and [Lep’12] and [Cla12]

ExerStats comparison



Stretch and muscle damage for even more growth

When a muscle is stretched under tension, micro damage occurs in the muscle fibers. The ROM of a muscle has during an exercise is a great indicator for its ‘stretching and damaging’ potential.

Why is this stretch under tension relevant? Well, in addition to muscle activation, muscle damage is another important factor for muscle growth. [Scho’10]


A deep squat is a great example of an exercise that puts the glutes under a BOATLOAD of stretch. Hence, this exercise is tremendous at causing micro damage (and thus growth) in this muscle.

Another exercise that’s great at stretching under tension is the Lunge. It’s been shown that a Lunge activates the glutes up to 50% more than a Squat[Lep’12]


Don’t squats give you big quads?

Indeed, Squats (and Lunges) activate the upper thigh muscles (such as the quadriceps) a great deal. This can result in bigger upper thigh muscles, which a lot of women don’t necessarily want (strange, a little leg muscle is just fine (even sexy) in my eyes).

However, it’s still important that you do Squats in order to increase the stretch under tension of the glutes, which will lead to more glute growth.

What can we do to specifically activate the butt during a set of squats, while limiting the amount of quad activation?

Try doing paused squats : emphasize the deepest part of the movement by pausing ‘in the hole’ before coming up again. [Cat’02]

Also: do not lean on your calves. This will take the tension out of the ‘stretching under tension’ we talked about earlier.

I assure you: try this once (using a lower weight than you normally would) and your butt will burn the entire next day. Look at this video on how to perform a paused squat.



Take-home message

Do you want to effective build a firm butt? Choose an exercise from the ExerStats that shows the highest mean activity for the upper and/or lower glutes. Make sure you pay attention to the Range of Motion, too!

These are some examples of such exercises:
Barbell hip thrust
American hip thrust
Bent leg kickback


Make use of the fact that Squats put great stretch under tension on the glutes. This will signal even more growth!

Do you want your upper thigh muscles to remain relatively small? Try pausing in ‘the hole’ of your Squats. Use less weight than normal when doing this. Otherwise, you’re going to have to scream for help when you can’t get back up after 2 minutes of ‘pausing’ down there…

Finally, always make sure that you’re lifting progressively heavier weights over time. Getting stronger at an exercise goes hand-in-hand with growth in the activated muscles. [Mau’83] Strength is very easy to measure, so it will be easy to evaluate whether you’re on your way to that bootyliciousness you’re longing for.

Are you stuck on a certain weight for a certain exercise? Take a step back by decreasing the weight (by 10%, I would advise) and build your way back up to smash this plateau.

Now get going and build that butt of your dreams!


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