Knowing the main squat muscles worked can help you optimize your technique and gains. When I'm helping athletes get a bigger squat, I try to teach a complete understanding of the movement's concentric and eccentric phases.
Certain muscles in the squat will work more or less depending on the range of motion, whether you're deep into the hole or driving through your sticking point, and which variation of the squat you're performing.
So, let's fully cover the squat muscles worked, including:
- Quadriceps (top of thigh): Your quads work the hardest at the bottom of the squat.
- Hamstrings (bottom of the thigh): Support glutes during hip extension.
- Core muscles (abs and obliques), specifically your erectors (back): Activated to prevent falling forward or flexing at the spine.
- Glutes (butt) and adductor magnus (inner thigh): Help extend your hips as you drive to standing.
- Upper back and lats: Support erectors and bar.
- Calves: Minor role at bottom of squat.
Overall, the squat is one of the most compound lower body exercises since it requires simultaneous action at all the primary joints, including hips, knees, and ankles.
In this article about squats, including the muscles worked, I'll discuss what each muscle is responsible for in this exercise. I'll explain how different muscles are used in different squat variations, including the low bar squat, high bar squat, pause squats, pin squat, wide-stance squats (sumo squats), front squats, goblet squats, split squats, and jump squats.
I'll also talk about how to identify weak muscle groups in the squat and what you can do about it to become a more efficient squatter.
Let's dive into the squat muscles!
- Squat Biomechanics: How Joint Angles Impact The Muscles Used
- Squat Anatomy: Which Muscles Are Worked In The Squat
- Identifying Weak Muscles In The Squat
- Muscles Used in Different Variations Of The Squat
Table of Contents
Squat Biomechanics: How Joint Angles Impact The Muscles Worked
Before we look into the main squat muscles worked, let’s cover some biomechanics and how each squat muscle group works together in the exercise.
Whether doing a bodyweight squat or a heavy barbell squat, this compound exercise requires joint action at the hips, knees, and ankles. As a result, the squat muscle groups in the lower and upper body are required to overcome the forces on these joints to execute the movement properly.
The load in the squat should be directly over the mid-line of the foot as you descend to the bottom.
When your hips move back behind this line and your knees move forward, you stress these joints more. The greater the distance between the line of force and your joints, the harder your muscles need to work to overcome the external load.
Having your hips and knees travel in an opposing direction to the line of force in the squat is totally normal.
For example, if your knees do not travel forward during the squat, then they won't experience any stress, and your quad muscles won't be significantly loaded.
This might seem advantageous… However, it means that all the stress gets transferred to your hip extensors, which requires your glutes and low back to work much harder. Over time, this could result in injury if one joint or another experiences greater stress than what they are accustomed.
The basic biomechanical principle you need to understand is that joint action will require certain muscles to contract in order to flex and extend that joint properly. Joints will experience more or less stress the further they are in relation to the load, which requires your muscles to work harder.
If you're interested in reading more about whether it's safe to have your knees travel forward in the squat then take a look at my article where I discuss the biomechanics research.
Want to improve your squat technique?
Squats: Muscles Worked
So, what muscles do squats work out, and what are squats good for when it comes to muscle building and strength gains?
Whether you’re doing bodyweight squats or weighted squats, muscles worked include:
- Quadriceps (top of thigh)
- Glutes (butt)
- Adductor magnus (inner thigh)
- Hamstrings (lower thigh)
- Erectors (mid-back)
- Abdominals and obliques (stomach and chest)
- Upper back and lats
- Calves (lower leg)
Certain muscle groups are more or less engaged, depending on which variation of the squat you're doing, the speed of the squat, and the range of motion emphasized. We'll explain this later, but first, let's break down each muscle worked in the squat and its role.
When most people hear the question, ‘what muscle group do squats work?’ their first answer is usually the quads.
The quadriceps are a group of four muscles (hence the term ‘quad’ in the name), and they are the primary muscles used to extend the knee.
At the deepest range in the squat, the quads work the hardest to extend the knees out of the bottom.
Furthermore, as you remember from the biomechanics section, the knees will travel in front of the line of force as they descend into the squat. The further your knees travel forward, the stronger your quads must be.
So the deeper you go, and the greater your forward knee bend, the more you can expect the quads to work. If your quads get overly sore from squatting, check out my article on quad soreness after squatting to learn how to prevent and reduce soreness.
If you have long legs, check out my article on How To Squat With Long Legs to see how your quad activation changes as a tall lifter.
When considering the question of ‘what do squats work,’ it’s not just the quadriceps we should consider. The posterior chain of your body also works hard when you’re squatting.
The posterior muscles used in squats include the gluteal muscles and the hamstrings. The glutes comprise three muscles: glute maximus, glute medius, and glute minimus. For the purposes of the squat, we're going to discuss the glute maximus and medius.
The glute maximus is the ‘meaty' part of the glute that you sit on. The glute maximus extends the hips, which is important for the squat lockout.
As you remember from the biomechanics section, the hips will travel behind the line of force as it descends into the squat. As you stand back up, the hips need to rise up and forward to come back in line with the line of force.
Therefore, the glute maximus serves an important function in the top range of the squat in order to bring the hips into full extension.
The glute medius is the side part of your glute. It abducts the hip — in other words, taking the leg out laterally like a ‘side step.'
Keeping the hip abducted in the squat will ensure your knees track over your toes properly. Without a strong glute medius, your knees might cave in during the squat, increasing the amount of shear force at the knee joint.
Adductor Magnus (Inner Thigh)
The adductor magnus muscle of the inner thigh also has a role in hip extension.
It performs a similar function to the glute maximus, which allows the hips to extend fully. However, it plays more of a role in the mid-range of the squat before the glutes take over for the final hip extension.
Furthermore, the adductor magnus will work more to extend the hips if you have a wider stance squat, such as in a sumo squat, and less if you take a narrow (shoulder-width) stance.
Curious about which squat stance is best? Check out my article on whether wide stance squats are better for powerlifting.
First, the hamstring acts as a synergist to support the glutes in hip extension. As the knees straighten, the hamstrings are engaged more in order to bring the hips to the bar. However, the hamstrings are only contracting a small amount here and the primary driver of hip extension is still the glutes.
Second, the hamstring acts as a stabilizing muscle to support the knee joint. When your knees are in the greatest flexion in the bottom of the squat, the tension of the hamstrings helps stabilize the knee joint by countering the forces of the quads to extend the leg.
If your hamstrings get overly sore in the squat, check out my article on hamstring soreness after squats.
Your erectors are the muscles that run along the outside of your spine. They attach at the top of the pelvis, ribs, and the spine itself.
The erectors have a role in keeping the spine stiff and extended throughout the squat. Essentially, they prevent the back from rounding or flexing forward.
This is an important function because if the back rounds while squatting, the stress at the vertebrae level will increase. The spine should stay rigid to transfer the force effectively from your knees and hips into the bar.
Let's quickly discuss forward torso lean in the squat and its impact on the erectors.
Everyone will have a natural forward torso lean in the squat based on their individual leverages. If you have longer legs and a shorter torso, you'll experience more forward lean than someone with shorter legs and a longer torso.
The more forward torso lean you have in the squat, the harder your spinal erectors need to work to keep your back rigid.
This is not a bad thing. This just means that your erectors will need to be much stronger if you have more forward torso lean.
You also need strong erectors to prevent your back from rounding in the squat.
Abdominals and Obliques
The abdominal muscles and obliques are what are called “antagonist stabilizers” in the squat.
An “antagonist stabilizer” will help maintain the postural alignment of specific joints.
In the squat, the abdominals and obliques help stabilize the vertebral column and pelvis. They do this by preventing the erectors from pulling the spine into hyperextension.
As you'll remember, the erectors' job is to prevent the spine from flexion (rounding). The abdominals and obliques prevent the spine from extending (arching back) or twisting.
With weak abdominals and obliques, the erectors don't maintain as much tension potential as they otherwise would.
Upper Back and Lats
The upper back muscles and lats work to keep the bar position fixed in place, even when you’re in a resting, standing position at the start of your squat.
If the upper back and lats aren't tight enough, the bar will shift up or down on the back throughout the squat. Even micro-movements of the bar can cause instability through the core, causing your spinal erectors and abdominals/obliques to work much harder to hold the same position.
The muscles of the upper back and lats also support the erectors in maintaining spinal stiffness since the erectors attach at the upper back as well.
Many people are surprised that the calves have a (small) role in the squat.
As you descend deep into the squat, your ankle flexes, and your shins move forward. The soleus muscle, the outside of the calf, brings the shin to a vertical position as you stand back up in the squat.
Identifying Weak Muscles In The Squat
You should now understand the muscles involved in squats and how they function together to complete the movement.
Let's now discuss how to identify weak muscles in the squat so that you can target them more specifically through your exercise selection and programming.
Identifying weak muscles is important because they often contribute to technique deficiencies. If a muscle does not do its job properly, the body will compensate in some way to prevent you from failing the squat movement. These compensations are generally not good because other muscles get overworked by additional stresses being placed at the level of the joint.
Technique deficiencies or lack of proper form in the squat could be an entirely separate article, but I'll broadly address weak muscles based on the squat's ‘bottom' and ‘top' end range of motion.
Any muscular imbalances between the right and left side can cause you to lean to one side. If that's you, check out my article on How To Fix Leaning To One Side While Squatting.
Struggling At The Bottom Range
The deeper you squat, the more your knees bend forward, and the more your quads need to work. This is the case when squatting ass-to-grass.
If you have difficulty in the bottom end of the squat, you will struggle to return to a standing position from the deepest part of the squat up to about half range. This is likely due to your quads being too weak.
However, you won’t all of a sudden fail in the bottom range before at least grinding a few reps out. As you grind reps in the squat, you may notice some compensation patterns occurring that signal your quads are fatiguing.
You'll want to pick up on these signals as much as possible.
When your quads fatigue, your body will want to shift the loading demands from your knee extensors to your hip extensors to finish the movement. Again, the body will not fail before trying everything possible to leverage the weight.
To shift the loading demands from the knees to the hips, your body will hinge forward, and your hips will pop up out of the bottom of the squat. This will look like you are in a good morning squat position with your legs relatively straight and your back horizontal to the ground.
This is the body's way to get your glutes and low/mid-back more involved in the range of motion in order to complete the movement.
If you find yourself in this position, recognize that you have a quad weakness and implement squatting variations that will increase the strength of your knee extensors. These are variations such as front squats, pause squats, and leg presses or hack squats, which we'll cover in more detail later.
Struggling At The Mid & Top Range
As you drive out of the bottom of the squat and enter the mid/top end of the squat, the greater your glutes, adductor magnus (inner thigh), and hamstrings need to work to extend the hips.
A sliding effect happens where the closer you get to a standing position, the less your quads are activated and the harder your glutes and other hip extensors need to work.
If you have difficulty in the mid/top end of the squat, you’ll be able to stand up out of the hole but fail somewhere above your thighs being parallel. This is likely due to weak hip extensor muscles, which will fail to bring your hips up and forward underneath the barbell.
It's much harder to compensate for a movement pattern in the top range of a squat. However, your hip extensors would shift the loading demand to your quads by trying to push the knees forward more. This is tricky to notice, but it would look like you're squatting on the front part of your foot to try and bend your knees.
Even though this would be an effective compensation strategy to push through your sticking point, it would feel awkward. As you shift the load to the front part of your foot, you might feel off balance.
So rather than grinding through a rep by trying to bend the knees forward more, it's more likely that you'll come up in the squat with decent speed and then stop dead in your tracks without having the ability to grind.
This would mean that your glutes, adductor magnus, and, to a lesser extent, your hamstrings need to be addressed through several exercise variations, such as high pin squats, wide stance squats, and Romanian deadlifts.
Muscles Used in Different Variations Of The Squat
Each squat variation will involve your knee and hip extensors more or less, but the different muscles targeted by squats vary slightly depending on the type of squat you’re doing and your squat position.
As part of your programming, you should select squatting variations to adjust the squat muscles targeted and focus on areas for development.
You can emphasize your knee or hip extensors more depending on where you fail in the squat or notice the movement breaking down.
We will discuss the following variations and the squat muscles used in each:
- Low bar squat
- High bar squat
- Pause squat
- Pin squat
- Wide stance squat
- Front squat
- Goblet squats
- Split squats
- Jump squats
Low Bar Squats Muscles Worked
- Spinal erectors
The low bar squat or basic squat is one of the most common variations you’ll see in a gym. It is considered a hip-dominant movement and will use more muscles of the posterior chain, such as the spinal erectors and glutes.
You will place the barbell a few inches lower on the back. So rather than resting the bar on your upper traps, you'll place it at the top of your rear delt.
With a low bar squat, you'll have slightly more forward torso lean. You'll hinge from your hips more and flex into your knees less in this position.
This is not to say that your quads don’t work at the bottom of the squat. They don’t work as hard as other squat variations requiring more forward knee bend in the hole.
The low bar squat is the default powerlifting squat because you can lift more weight on a one rep max squat. This is because your quads will get maxed out eventually, and you'll need to shift the loading demands to the posterior chain, which doesn’t operate at ‘full capacity' in other squat variations.
If you want to read more about low bar squatting and its advantages, check out my article on where you should put the bar when squatting.
High Bar Squats Muscles Worked
- Spinal erectors
The high bar squat is considered a knee-dominant movement and will require your quads to work much harder.
In the high bar squat, you will place the barbell on your upper traps just below the big bony bone at the bottom of your neck (C7).
With a high bar squat, you'll be slightly more upright. You'll be hinging from your hips less, and bending your knees forward more.
When doing a high bar squat, you'll want to think about actively pushing your knees forward as you get to the bottom range. This will require you to use your quads more to drive up because of the greater angle at your knee joint.
The high bar squat is the choice of many Olympic weightlifters because the snatch and clean and jerk require excessive forward knee bend. Therefore, they need to use a squat variation that places large loading demands on the quads. In other words, the high bar squat will transfer more to their sport.
One quick note: the more you bend forward into your knees though, the greater your ankle mobility needs to be. So if you have any restrictions at the ankle it might be harder to drop your hips below parallel. If this is the case, then you likely won't get the quad activation you're seeking by doing the high bar squat.
If you struggle to squat below parallel, you can read my 9 tips to squat deeper.
Pause Squats Muscles Worked
- Spinal erectors
Pause squats are a variation of the basic squat. They are considered a bottom-end squat variation where you'll pause in the hole for 1-3 seconds.
This will put more loading demand on your quads because you spend more time under tension with your knees bending forward at the bottom of the squat.
To get the most benefit from the pause squat, you'll want to make sure you do two things properly:
- Maintain as much muscular tension as possible, and do not ‘relax' at the bottom of the squat. Actively keep your quads tight and your torso position rigid.
- Drive up from the pause by extending from the knees, not by shifting the loading demand to your hip extensors. If you use your hip extensors, it will look like your hips are popping up out of the bottom, where your torso becomes more horizontal to the floor.
The load is likely too heavy if you can't maintain muscular tension or drive up from the pause by extending from the knees first. You won't benefit from activating your quads to the fullest extent.
You can perform the pause squat in either a high or low bar position. But, if you want even more quad activation and lower body muscle growth, choose the high bar position.
You'll also activate your quads more if you squat in a narrow stance.
Pin Squats Muscles Worked
- Spinal erectors
The pin squat can be considered both a bottom-end and top-end squat variation, depending on how you set up the movement.
In the pin squat, you'll initiate the movement downward, and at some point, the bar will hit the safety pins in the squat rack. The bar load will come to a dead stop, and then you'll push up and back into the bar to drive it off the pins to standing.
If you want to target more of your quads, you can set up the pins in a lower position so that the barbell hits the pins at or below parallel.
If you want to target more of your glutes and other hip extensor muscles, you can set up the pins in a higher position so that the barbell hits the pins above parallel.
The pin squat is unique compared to the pause squat because the bar weight will completely deload on the pins. Your body will need to generate a higher rate of force development to initiate upward movement of the barbell — the speed at which your muscles need to contract and develop force. As a result, it's a much more physically demanding variation.
For my athletes, I generally don't use the pin squat to target the knee extensors. I only place the pins in a higher position and use the pin squat more to target the glutes and other hip extensor muscles. I find most athletes respond better to pause squats to build quad strength, and doing low pin squats tend to beat athletes up a bit more.
Wide Stance Squats Muscles Worked
- Hip adductors (outer thighs)
- Spinal erectors
The wide stance squat is considered a hip-dominant movement. The main squat muscle target with this variation is the glutes.
A normal stance width for most people is slightly outside of shoulder-width distance. A wide stance squat is considered somewhere between 1.5-2X shoulder-width distance.
To understand what muscles are involved in the wide stance squat, I want to examine two studies.
A study by Escamillia et al. (2001) showed that narrow, medium, and wide stance squats were all considered ‘knee-dominant' movements. Regardless of your stance, you'll still be required at some point to push your knees forward to get the required squat depth.
To back this up, a study by Paoli et al. (2009) showed that narrow, medium, and wide stance squats all had the same level of quad activation. However, the biggest conclusion was that there was greater glute activation in the wide stance squat.
This means that no matter what stance you pick, you will get the same level of quad activation. However, the wide stance squat will allow you to place even more loading demand on the glutes.
If you squat fairly narrowly, consider implementing wide stance squats as an exercise variation in your program to gain greater glute activation. This is important if you have a mid/top-end weakness in the squat.
Front Squats Muscles Worked
- Spinal erectors
The main front squat muscles worked are the quads, as the front squat is considered a knee-dominant movement.
To set up the front squat, you'll place the barbell on the front part of the shoulders.
This position will force you to maintain an upright torso, even more so than I described previously for the high bar squat. As such, your quads will work much harder because your knees will drive forward more to get the required squat depth.
Unsurprisingly, this bottom position requires the most mobility in your knees, ankles, and wrists compared with other squat variations. For these reasons, it's a more complex movement to learn. But it's worth getting better at if you want to work your quads in a squatting variation.
An added benefit to the front squat is more muscle upper-back muscle recruitment. This is because you need to stabilize through the muscles in your upper back to prevent your elbows from dropping forward and the barbell from falling off your shoulders.
The front squat is the squatting variation of choice for all Olympic weightlifters because it's a necessary movement pattern in the clean and jerk.
For a more detailed breakdown of the front squat, check out my article comparing the front squat vs. trap bar deadlift.
Goblet Squats Muscles Worked
- Spinal erectors
Goblet squats are limited by the amount of weight you can hold in your hands, so they aren’t the most effective variation if you want to build muscle and maximize your squat strength. However, they are a great movement to add to your workouts when you want to increase your training volume. They’re also a good warm-up exercise before you get into heavier barbell squats.
This squat variation focuses more on your anterior chain (quadriceps), although you will get some posterior chain activation. It’s an ideal alternative to back or front barbell squats if you have limited shoulder, wrist, and ankle mobility. You can place two small weight plates under your heels to achieve a deeper squat.
Split Squats Muscles Worked
- Hip adductors (outer thighs)
- Hip abductors (inner thighs)
- Ankle stabilizers
- Spinal erectors
Split squats are types of single-leg squats that work one leg at a time while your other leg is planted or on an elevated surface behind you.
As with goblet squats, split squats won’t be your heaviest lifts. They’re limited by the weight you can hold in your hands and your balance. However, they are effective for building stability, particularly in your abdominal muscles and ankle stabilizers.
You can adjust your stance in split squats to target the hamstrings, glutes, or quads.
Adopting a wider stance with your front leg further out in front will emphasize your posterior chain more. A narrower stance with your front leg closer to you is better for targeting your quadriceps. Hold the dumbbell or weight plate on the same side of the body as the front leg to make your stabilizer muscles work harder.
Jump Squats Muscles Worked
- Spinal erectors
A jump squat is a dynamic bodyweight squat used to increase power in the entire body, particularly the lower body muscles. It is also great for adding volume to your training program without fatiguing your muscles with excessive heavy compound exercises.
Jump squats are explosive and train your fast-twitch muscle fibers, helping you to build power and strength in your quads, glutes, hamstrings, and calves. Your core will also get a good workout.
Frequently Asked Questions
Do Squats Help Your Abs?
Yes, squats help your abs. You need to brace your core to keep your torso upright and stabilize your entire body during squats. Therefore, heavy squats will increase strength in both your anterior core muscles (abs) and posterior core muscles (spinal erectors and stabilizers).
Do You Need to Squat Heavy?
If you want to gain lower body muscle strength and power, you should squat heavy. However, incorporating lower-weight, higher-rep training can help to maximize your progress and build muscular endurance. To enhance muscular endurance, you can also benefit from doing bodyweight squat variations, such as jump squats.
How Long Will It Take To See Results From Squats?
There is no ‘one size fits all’ when it comes to seeing squat progress. New lifters can start seeing results after just a few weeks (known informally as ‘newbie gains’), whereas advanced lifters will progress more slowly. Your progress also depends on your programming and whether you’re using proper form.
The squat muscles worked in variations of all kinds, including the knee, hip, and back extensor muscles. However, different muscles will work more in certain parts of the movement.
In the bottom of the squat, you'll use more quad muscles to extend the knee out of the hole. As you transition into the mid and top-end range of motion, you'll use less quads and more of the glutes, adductor magnus, and hamstrings to extend the hips. The more forward torso lean you have, which will vary depending on your individual mechanics, the greater your erectors will work.
If you want more quad-dominant squat variations, use the high bar, pause, front, or low pin squat.
If you want more glute and other hip extensor variations, use the low bar squat, wide stance squat, or high pin squat.
What To Read Next:
- Goblet Squat vs Front Squat: How-To, Differences, Benefits
- Hip Dominant vs Knee Dominant Exercises (Simple Guide)
- Can You Build Muscle With Powerlifting? (Yes, Here’s How)
Escamilla, R., Fleisig, G., Lowry, T., Barrentine, S. (2002). A three-dimensional biomechanical analysis of the squat during varying stance widths. Med Sci Sports Exercise. 33(6): 984-998.
Paoli, A., Marcolin, G., Petrone, N. (2009). The effect of stance width on the electromyographical activity of eight superficial thigh muscles during back squat with different bar loads. Journal of Strength and Conditioning Research. 23(1): 246-250.
About The Author
Athina is a Biochemistry and Genetics graduate, and a qualified personal trainer with a passion for women’s health and fitness. She is passionate about helping women to learn more about the importance of the menstrual cycle and how to balance their hormones. She is the host and producer of Fertility and Freedom podcast, which covers all things women’s health and hormones.