Parallel Squats vs Deep vs 90 Degrees: How Low To Go?

If you want bigger quads, how deep should you squat? Is squatting to parallel good enough? Or are rock bottom ass-to-grass (ATG) squats the only way to go?

Why Is Squat Depth Important?

Squat depth refers to how low you squat down during the exercise.

Choosing the right squat depth is important, because it allows you to get the balance right between effectiveness and safety.

Half squats, for example, are easier to do than full squats. But they’re less effective when it comes to stimulating growth in your lower body.

On the flip side, rock bottom squats do a better job at stimulating growth in the hips and thighs. But most lifters will find them harder to do properly. Squatting ATG with poor technique does expose you to an increased risk of injury.

What most lifters want is a squat depth that allows them to stimulate the maximum amount of muscle growth with the minimum risk of injury.

So, what’s the answer? How far down should you squat?

You should squat to a depth that allows you to maintain good form. By that, I mean you should go no deeper than the point where you lose the arch in your lower back. This may be slightly below or slightly above parallel.

It’s far better to be an inch or two on the high side than go too deep and end up with a crippling back injury because of it. Even squatting above parallel is still deep enough to make your quads bigger and stronger.

However, it is important to reach a consistent depth, so you have a point of reference to measure your progress.

Don’t delude yourself into thinking that you’re increasing your strength when all you’re really doing is decreasing your depth in order to lift heavier weights. Have a firm standard for what constitutes a squat, and stick to it.

What is a Parallel Squat?

Squatting to parallel involves squatting down to the point where your femur, the large bone in your thigh, ends up roughly parallel to the floor.

Viewed from the side, your hip crease (called the inguinal crease) will drop slightly below the level of your knee joint.

The middle squat below (image B), which comes from this study, gives you a better idea what a parallel squat looks like.

That’s a parallel squat. Anything above that doesn’t really count.

It’s actually lower than you think, and involves flexing the knees to around 125 degrees. Very few people in the gym get that low, and most lifters will stop short of hitting parallel.

How to Do a Parallel Squat

In the video below, Canadian bodybuilding champion Jeff Nippard shows you how to do the back squat.

Here’s how it’s done:

• Rest the bar across your traps and keep tight hold of the bar.
• Step back from the rack and assume a (roughly) shoulder width stance.
• Your toes should point slightly outwards rather than straight ahead.
• Maintain this stance throughout the exercise.
• Brace your abs before starting the descent.
• Your knees and toes should point in the same direction while you descend.
• Maintain the natural arch in your lower back throughout the exercise.
• Bend at the knees until your thighs are parallel to the floor.
• Don’t let your heels lift off the floor. If you’re having trouble keeping your heels down, you can always try wearing some weightlifting shoes. These shoes keep your heels in an elevated position, and provide a lot more stability than regular running shoes.
• Return to the starting position.

What Muscles Do Squats Work?

The barbell squat is a highly effective way to train the quadriceps, which is made up of four different muscles:

• Vastus Medialis
• Vastus Lateralis
• Vastus Intermedius
• Rectus Femoris

Of the four, the squat works mainly vastus medialis, vastus lateralis and vastus intermedius. Rectus femoris is recruited, but not to the same extent as the other three muscles that make up the quads.

The gluteus maximus, erector spinae and adductors are also involved, but to a lesser degree.

How Deep Should You Squat?

Ideally, you should squat no deeper than the point where you lose the arch in your lower back. This may be slightly above or slightly past the parallel position.

That is, some lifters will find that a parallel squat is as deep as they can go. Others will need to stop slightly above parallel. Only a very small number of people can do ATG squats without losing the natural curvature in their spine.

In fact, one of the classic signs that your squat technique needs some work is so-called butt wink, where your pelvis tucks under and the lumbar spine rounds excessively.

If you blindly follow the advice to squat ATG (or even to parallel) while ignoring what’s happening to your lower back, the potential for some kind of disc injury is greatly increased.

Neutral spine isn’t a single position that your back never deviates from. Think of it more like a neutral zone, or a range that your spine can move within while still posing a low risk of tissue damage.

Your ability to maintain a neutral spine during the squat depends on a number of factors. These include:

• The strength of the muscles around the hip
• The flexibility/mobility of the hip and knee joint
• The relative lengths of your torso and thighs.

If you have relatively long thighs, for example, you’ll have to shift your weight back by leaning forward as you squat.

Combine this with a lack of flexibility/mobility in the hip area, or lack of strength in the spinal erectors, and you’ll find it very difficult to get below parallel without losing the arch in your lower back.

Are Deep Squats Bad for Your Knees?

Many health professionals recommend squatting no lower than parallel or higher. This is based on the idea that going too deep can generate dangerously high forces at the knee joint, increasing the risk of a knee injury.

It’s true that squatting past parallel tends to increase forces at the knee, even accounting for the fact that you’re lifting lighter loads [5].

However, whether this is going to increase your risk of a knee injury depends every much on the individual in question.

There are many potential sources of painful knees, and something that has an adverse effect on knee health in one context isn’t necessarily going to have the same effect in another.

The fact that an exercise puts “stress” on a particular joint isn’t necessarily a bad thing.

Tendons, ligaments and even bone can adapt to various stresses in such a way that they’re better able to cope with that stress in future.

That’s how your muscles grow. You expose them to a level of stress they’re not accustomed to, which in turn stimulates a positive adaptation, namely muscle growth.

The problem with stress is when it’s applied in such a way that whatever tissue being stressed can’t adapt.

But that doesn’t necessarily make squatting past parallel a bad idea, just a bad idea for some people in certain situations.

How Deep Should Squats Be for Muscle Growth?

If you can’t squat ass-to-grass (ATG), don’t worry. Squatting to parallel is still an effective way to make your quads grow.

In fact, research that compares the full-depth and parallel squat shows very little difference in muscle activity between the two.

Dr Rafael Escamilla, a Professor in the Department of Physical Therapy at California State University, reviewed a total 70 studies on the subject of knee biomechanics during the squat [1].

He found that squatting roughly to parallel is enough to achieve very high levels of muscular activity in the quadriceps, which is going to make your legs bigger and stronger.

Deep Squats vs 90 Degrees

A study published in the European Journal of Applied Physiology by a team of Japanese researchers, looked at the rate of growth in various muscles after 10 weeks of squatting [4].

• Group one squatted to 90 degrees of knee flexion.
• Group two went all the way down, defined as 140 degrees of knee flexion.

The image below, which comes from this study, give you an idea what those knee flexion angles look like:

A = Above parallel (roughly 95 degrees knee flexion)
B = Parallel (roughly 125 degrees of knee flexion)
C = Below parallel (roughly 140 degrees of knee flexion)

So, what happened? Which group gained the most muscle?

MRI scans taken at the start and end of the study show no significant difference in the rate of quad growth between the two groups.

That is, whether the men squatted to 90 degrees of knee flexion, or ATG, the increase in quad size was virtually identical. Squatting below parallel wasn’t necessary to stimulate growth in the quads.

What about the hamstrings?

Neither the full squat nor the 90 degree squat led to a change in hamstring size over the course of the 10-week study.

That’s because hamstring muscle activation during the squat is relatively small. If you want to train your hamstrings, your workouts will need to include exercises like the Romanian deadlift or leg curl.

The squat isn’t an effective way to train the calves either. They are involved in the exercise, but not to a degree that’s sufficient to stimulate much in the way of muscle growth.

If you want bigger calves, your lower body workouts will need to include exercises like the standing or seated calf raise.

Although full squats didn’t make the quads grow any faster than squatting to 90 degrees, they did lead to a faster rate of muscle growth in both gluteus maximus and the adductors.

Gluteus maximus

• Full + 6.7%
• 90 degrees + 2.2%

Adductors

• Full + 6.2%
• 90 degrees + 2.7%

Of course, this doesn’t mean that if you don’t do full squats, your glutes are doomed to stay in the muscle-building slow lane.

Squats aren’t the only show in town. There are plenty of other lower-body exercises you can do, such as the same leg chain lunge, step ups or the Bulgarian split squat.

These exercises allow you to work through a larger range of motion while your torso remains upright. As a result, they’re harder on your glutes while simultaneously being a lot easier on your spine.

Some people will tell you that if it’s not ATG, squatting won’t make much of a contribution to gains in lower body strength and size because it wasn’t done through a full range of motion.

Many of these same people will then go on to recommend the deadlift as one of the best overall mass building exercises for the entire body. That’s despite the fact there is not one muscle group that is taken through a full range of motion during the deadlift.

How To Improve Squat Depth

1. Warm up properly. Squatting to a decent depth is going to require a thorough warm-up, which helps to prepare the joints, the muscles and the nervous system that controls those muscles for deeper squats.

Personally, I like to start a lower body workout with 10-20 minutes of light cardio on an exercise bike or rowing machine. A bike or rowing machine is a better choice than jogging or walking, mainly because the knees and hips are taken through a larger range of motion.

Then I’ll move to the squat rack, and do a set of 15-20 reps with an empty bar. This is followed by 3-5 progressively heavier warm-up sets. 

However, there have been many times when I’ve ended up doing 7-8 warm-up sets in total, especially if I’m training early in the morning in a cold gym, and my joints are feeling a bit creaky.

Including some targeted stretching and/or foam rolling in the warm-up may also be useful if there are areas of your lower body that feel “tight,” particularly the calves, hips or inner thighs [5].

2. Experiment with foot positioning. Not everyone is built in the same way, and it’s worth experimenting with different stances and foot positions until you find one that feels right.

You might start out with your feet turned outward slightly. Try a deep squat. Then turn them out a little more. Try a deep squat again. Notice which foot position feels better and allows for the deepest squat.  

Do the same thing with your stance. Start with your feet around shoulder-width apart. Then, experiment with different stances, some slightly wider than shoulder width, and some slightly narrower, until you find one that allows for the largest range of motion.

3. Change your footwear. Rather than try to squat in shoes with spongy heels, you want something with a flat, firm insole and little or no cushioning. Because the heel isn’t compressible, flat shoes give you a much more stable position from which to drive up.

It’s also worth experimenting with squat shoes, a hard-bottomed shoe with an elevated heel, to see if they allow you to squat deeper. 

Squat shoes are particularly useful if you have limited ankle mobility, which can cause your heels to lift when you try to squat low. This in turn makes it very difficult to stay balanced. 

But with squat shoes, your heels are already slightly elevated, allowing you to squat deeper while still having your heel supported.

I’ve used Adidas Adipower weightlifting shoes in the past, and found that I can squat a little deeper compared to wearing shoes without an elevated heel.

4. Lighten the load. Many people struggle with deep squats simply because the weight they’re lifting is too heavy. If the weight is too heavy, you’ll struggle to stand up from the bottom position. Try reducing the load by 20% or so to see if that allows for a deeper squat.

There’s no rule that says all your squats have to be done to the same depth. You might do most of your squats with a heavy weight in the 5-8 rep range, hitting parallel or slightly above, but follow that up with a couple of light sets done through a much larger range of motion.

5. Try front squats. Unlike the back squat, where the barbell is positioned behind your head, in the front squat it rests across the top of your shoulders. 

This means your torso has to remain in a much more upright position, which typically allows for a deeper squat. If your torso didn’t remain upright, the bar would end up rolling off your shoulders.

One of the main benefits of the front squat is that it typically involves the use of lighter loads than the back squat, but hits the lower body just as hard [6].

In one trial, scientists measured muscle activity in the thighs and lower back during both front and back squats [7].

The front squat was shown to hit the leg muscles just as hard as the back squat, despite the fact subjects were able to lift a heavier load with the back squat.

6. Finally, be patient. Increasing your squat depth is going to take time. Start by squatting to a comfortable depth, be it 90 degrees, parallel or somewhere in between, and gradually work your way lower over time.

Focus on maintaining proper form and avoid compromising your spinal alignment as you go deeper.

What’s the bottom line? How low should you squat?

Contrary to what the exercise police might say, there is no one size fits all recommendation when it comes to squat depth, and the ideal range of motion will vary from person to person.

You should squat to a depth that allows you to maintain good form. By that, I mean you should go no deeper than the point where you lose the tight arch in your lower back. This may be slightly below or slightly above parallel.

Unless you’re an athlete trying to improve your performance in a sport where you need to be strong in a deep squat position, don’t worry if you can’t get below parallel.

Squatting below parallel isn’t necessary to make your thighs grow. There are certainly advantages to squatting below parallel in the sense that your glutes and adductors will grow faster compared to a 90 degree squat.

But not everyone can squat below parallel and maintain good form at the same time. If you are one of those people, I’d suggest squatting as deep as you can, and then using other exercises (such as Bulgarian split squats, hip thrusts, lunges or step-ups) to work the muscles in your thighs and hips through a larger range of motion.

SEE ALSO: Squat Alternatives: Bad Knees, Back or Hips?

Frequently Asked Questions

How many days a week should I do squats?

Some advanced strength athletes have made impressive strength gains by squatting 4-6 days a week. But for most people, most of the time, squatting 1-3 days a week will do the job.

Is it better to squat heavy or light?

If you want to get strong, squatting with heavy weights and low reps is the way to go. And by heavy, I’m talking about doing most of your squats with a weight that limits you to somewhere between 3 and 5 reps.

For building muscle, you can train with heavy weights and low reps, or light weights and higher reps, and you’ll see a similar level of muscle growth.

I’d suggest doing most of your training in the 5-15 rep range. That’s heavy enough to put plenty of tension on the muscle, but not so heavy that you can’t control the weight. If I had to pick a single best rep range for building muscle, it would be 5-15.

Is squatting to 90 degrees the same as parallel?

A 90 degree squat isn’t the same as parallel. Squatting to parallel involves squatting down to the point where your femur ends up roughly parallel to the floor, which is roughly 125 degrees of knee flexion. A 90 degree squat is actually slightly above parallel.