Squat Depth: How Deep Should You Squat?

Key Points:

Deep squats (120–140° knee flexion) lead to greater muscle growth in the quads, glutes, and adductors than shallow or half squats (60–90°).
You improve your strength the most at the depth you train at. Deep squats, however, have greater carryover to shallow squats than vice versa.
The required squat depth in powerlifting is below parallel, i.e., when your hip crease is below the top of your knee.

How deep should you squat?

The barbell squat is the most classic leg exercise of all. It is excellent for building both leg muscle and strength, but depending on how you perform the squat, you might get different results.

One of the most important considerations in your squatting technique is your squat depth. In general, deep squats have been found to build the leg muscles better than shallow or half squats – even if you’re using much lighter weight.

In this article, we will examine squatting depth.

You will learn:

What is a deep squat?
What is powerlifting squat depth?
How deep should you squat for muscle growth?
How deep should you squat for strength?
Are deep squats dangerous?

Let’s get to it!

What Is a Deep Squat?

The definition of a deep squat is generally that you perform it to parallel depth or more. This is usually when your knee is flexed to about 120° (where 0° is when you’re standing straight with extended legs).

Some common definitions of different squat depths are:

Deep squat: 120° knee flexion or more
Half squat: 90° knee flexion
Quarter squat: 60° knee flexion

Here’s an image of me doing a half squat, with 90° knee flexion:

90 degree half squat — 90° knee flexion.

And here is an example of a 60° (left) and 120° squat (right):

For this particular model, a 120° squat makes the thigh bone parallel to the floor, and a deeper squat would then necessitate more than 120° knee flexion with this same squat style.

Here’s a GIF of me doing a deep squat, going below the point where my thigh is parallel to the floor:

In the sport of powerlifting, you are required to squat deep enough for your squat to count.

What Is Powerlifting Squat Depth?

Depending on the federation, the required powerlifting squat depth may vary. However, the most common depth requirement, and the one used in the International Powerlifting Federation (IPF) is that you squat below parallel.

Parallel, in this case, refers to your thigh bone relative to the ground, and it is usually judged by when your hip crease is below the highest point of your knee.

This typically occurs when your knee is bent to about 120° or more, but it varies with your squatting technique:

If you squat with a wide stance, low bar-style where your knees don’t track very far over your toes, you will reach parallel depth with less knee flexion.
If you squat with a narrow stance, high bar-style where your knees do track far over your toes, you will need slightly more knee flexion to reach parallel depth.

Powerlifting style low bar squat — The typical powerlifting squat: low bar position, wide stance with feet pointing out, and flat shoes. Requires less knee flexion.

Olympic style high bar squat — The typical weightlifting squat: high bar position, narrow stance with feet pointing forward, and shoes with raised heels. Requires more knee flexion.

When you compete in powerlifting, your goal is to lift as much weight as possible within the boundaries of the rules. You must also have a repeatable style (meaning that you can reproduce it consistently) and which doesn’t injure you.

Your powerlifting squatting depth should therefore be a depth that:

Lets you lift as much weight as possible.
Doesn’t injure you and is repeatable.
Meets regulation depth (hip crease below the knee for IPF and most other federations).

But what if you don’t care about powerlifting? What if you only care about building muscle?

How Deep Should You Squat for Muscle Growth?

Two training studies have compared muscle growth from deep squats vs. quarter or half squat.

The first one, published in 2013, had 17 young men train either deep squats (120° knee flexion) or quarter squats (60° knee flexion) three times per week, for 12 weeks.¹

The weights were progressively increased throughout the program, and muscle growth was measured by MRI, at several points across the thigh, 1 cm apart.

Results?

The deep squat group experienced significantly greater muscle growth in their quadriceps compared to the quarter squat group in all measurement sites except one, as seen below.

Muscle growth from shallow vs deep squat — Muscle growth at different sites on the quadriceps, 1 cm apart.

Both groups had small to non-existent muscle growth in the hamstrings (which squats don’t really train that well).

So – greater quadriceps growth from deep squats in the first of two studies.

The second study took things a bit further by examining how different squat depths influenced muscle growth in not only the quads and hamstrings but also the glutes and adductors.²

Yet again, a group of young men was selected to train free barbell squats, two times per week for 10 weeks.

They were divided into two groups, both of which trained slightly deeper squats than in the previous study:

One group trained deep squats to 140° knee flexion.
The other trained half squats, to 90° knee flexion.

Muscle volume was measured in the quadriceps, hamstrings, gluteus maximus and adductors, by using MRI to take several pictures and then multiplying the muscle area in each picture with the distance (1 cm) between each measurement point.

Results?

Significantly greater muscle growth in the glutes and adductors from deep (140°) squats compared to half squats (90°).

Muscle growth from deep squat vs half squats

Worth noting is that both groups experienced similar quadriceps growth, which stands in contrast to the previous study where 120° squats were superior to 60° for quadriceps growth. Does this mean that 90° squats are enough to elicit robust quadriceps growth, but not for glutes or adductors? Maybe. We’ll see what future research unearths.

Neither group experienced any muscle growth in their hamstrings.

In conclusion, deep squats (120–140° knee flexion) seem to build more muscle in the legs and glutes overall than shallow or half squats (60–90°).

Read more: Do squats work your hamstrings?

That’s muscle growth. Now let’s look at getting stronger.

How Deep Should You Squat for Strength?

Strength gains from squatting seem to be quite specific. Meaning: you get better at what you practice.

If you train in a long range of motion (i.e., squat deep) you will increase your strength pretty evenly in that whole range.
If you train in a short range of motion (i.e., half or quarter squat) you may increase your strength a bit more in that specific range than you would if you squatted deep, but less (or not at all) in ranges outside what you have practiced.

In the first study mentioned above, where subjects squatted to either 120° or 60°, the deep squat group increased their strength by about 20% in both deep and shallow squats. The group that trained shallow squats, however, increased their 1RM in shallow squats by 36%, but only increased their deep squat 1RM by 9%.

Strength gains from deep squats vs shallow squats

The second one had similar results: the group that trained deep squats improved the most in deep squats (32% vs. 12% for the half squat group) while the group that trained half squats increased their strength more in half squats (32% vs. 24% for the deep squat group).

Strength gains from deep squats vs half squats

Similar results have been seen in other studies with similar designs: you improve most at the squat depth that you train with, but deep squat training has better carry-over to shallow squats than vice versa.³ ⁴

Take away?

Squat to the depth that you wish to improve your strength at. If you’re capable of squatting even deeper than you “must”, it could benefit you to do some of your training to this deeper level.

OK, so we’ve got greater muscle growth and strength gains in a longer range of motion – that seems great! But aren’t deep squats bad for your knees?

Are Deep Squats Dangerous?

This was the research question posed in a meta-analysis published in 2013, titled Analysis of the Load on the Knee Joint and Vertebral Column with Changes in Squatting Depth and Weight Load, encompassing 164 different research studies.⁵

After going through the scientific literature, the researchers concluded that the fear of injury due to deep squats is unfounded. The advice to half- or quarter squat for knee health might even be counter-productive as it might not allow the knee joint to get stronger in its full range of motion.

Here’s a quote from the conclusion of the review:

When compared with half and quarter squats, in the deep squat, lower knee joint and spinal joint stress can be expected.
Provided that the technique is learned accurately under expert supervision and with progressive training loads, the deep squat presents an effective training exercise for protection against injuries and strengthening of the lower extremity.

It seems that deep squats are not only better for building muscle and increasing your strength in a long range of motion; they are also better for strengthening and maintaining healthy joints.

Conclusion and Practical Applications

To sum up:

Deep squats (120–140° knee flexion) seem to lead to greater muscle growth in the quads, glutes, and adductors than shallow or half squats (60–90°).
You improve your strength the most at the depth you train at. Deep squats, however, have greater carryover to shallow squats than vice versa.
The required squat depth in powerlifting is usually below parallel, i.e., when your hip crease is below the top of your knee, but this depends on the federation.
If you just want to train the squat to get bigger and stronger in general, find a squat depth that works for you, that is at least somewhere close to parallel, and that doesn’t cause you pain or injury. Then strive to get stronger at that depth.

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Read more:

Muscle group training guides for the squat: