Squats: Everything You Need to Know to Execute them Correctly

Squats: Everything You Need to Know to Execute them Correctly

We present to you: the best guide on know how to execute squats correctly.

What is a squat and what is it used for?

The squat is an exercise in which the force of gravity must be overcome through a triple flexion-extension of the ankles-knees-hips; with or without an external load.

It’s used to develop muscle mass and lower body strength.

In turn, this improves athletic performance thanks to the high neuromuscular demands of the exercise due to the high volume of muscle mass involved and the need to stabilise the position through the activation of a large number of muscles that act as synergists of the movement (stabilisers, auxiliaries… depending on the source that you consult, they’ll go by either name).

Deep back squats

Figure I. Deep back squat.

I’m not going to go any deeper into this aspect as squats have been covered extensively in a whole host of blog articles – including one by me, where I explain the benefits of including squats in your training routines.
So, if you already know that you want to include squats in your routine… I’m going to explain everything you need to know to do a perfect squat! 😉

Fundamentals of the squat as a movement


The squat is nothing more than a movement with 4 phases:

  • Initial isometric phase: keep your body upright, as when standing, usually with an external load.

Phase 1

Figure II. Phase 1 of the squat; initial isometric or unracking position.

  • Eccentric phase: Regulate your muscle contraction to control the movement, with the external resistance greater than your muscle strength, causing you to flex your ankles-knees-hips.

Phase 2 Squats

Figure III. Phase 2 of the squat; descent or eccentric phase.

  • Concentric phase: Increase the intensity of your muscle contraction to overcome external resistance and extend the ankles-knees-hips.

Phase 3 Squats

Figure IV. Phase 3 of the squat; ascent or concentric phase.

  • Final isometric phase: Just the same as the initial isometric.

Phase 4 Squats

Figure V. Phase 4 of the squat; final isometric position or reracking.

Performed in sequence, this is the complete movement:

Front Squats

Figure VI. Kinematics of a front squat with dumbbells.


The squat load (be it a bar, a dumbbell, or your own body weight) subjects us to an external force (gravity + weight), which, depending on the internal force we produce (through body movement), will force us to overcome resistance and complete the lift (or not).

  • If the load force generates 2000N and you alone are only able to generate 1900N, you won’t be able to lift the load;
  • If you generate 2000N, you’ll maintain an isometric position until you’re fatigued and then start generating less, and then you’ll fail;
  • If you generate 2100N, you’ll overcome the load.

The force you generate is variable along the movement and joint axis.

That’s why performing a deep squat (maximum knee flexion) is more difficult than a quarter squat.

The force we can apply is conditioned by the internal moment, which in turn depends on various factors:

  • Uncontrollables: Length of our bones, place of insertion of our muscles, joint architecture…
  • Controllables: Technique and contracting capacity.
The best lifters have short, highly hypertrophied legs and wide insertions of the glutes, quads and calves

That’s why it’s the “classic” build of elite weightlifters, who can do squats from the correct position.

Ideal body architecture for a squats

Figure VII. Example of the ideal body architecture for a squat.

How do we contract the muscles?

When squatting, we have 4 large joints directly involved in the movement: the ankles, knees, hips, and spine.


These are flexed according to the angle they form with the tibia during the eccentric phase; and they are extended in the concentric phase through action from the:

  • Calves.
  • Soleus.

Ankle dorsiflexion Squats

Figure VIII. Examples of different dorsiflexion ranges.


These flex during the eccentric phase, and extend during the concentric phase through action from the:

  • Quadriceps

Knee extension Squats

Figure IX. Example of knee extension through quadricep action.


These flex during the eccentric phase, and extend during the concentric through action from the:

  • Hamstrings.
  • Gluteus maximus.
  • Adductors.

Hip extension

Figure X. Example of hip extension.


This is extended (in the neutral position) during both phases through action from the:

  • Spinal erectors.

Spine Squats

Figure IX. A. Loss of spine curvature/ B. hypercyphosis / C. Maintenance of spine curvature.

If we integrate all these joint movements that occur through muscle contraction, we’ll find this:

Direction of forces

Figure XII. Direction of forces in the ascent (left) and descent (right) phase during a squat.

The arrows point in the direction of joint movement.


The core is an “exception”, as in itself it doesn’t generate movement during the squat, but it does act as a general stabiliser, and it’s also the centre of force transmission.

Core Squats

Figure XIII. Relationship between core stability development and squat performance.

That’s why we’ll find lifters who, despite having incredible bench press numbers, aren’t able to extrapolate them to the squat; the limitation is the lack of ability to transfer the extension force of the lower limbs.

A weak core condemns a lifter to a mediocre squat.

Are there any risks in performing Squats?

As with any exercise, if you balance the training load and stimulus (aggression) correctly, you won’t have any problems.

It’ll depend on the technique, the range of motion, your ability to tolerate tension…

But both the knees and the spine are safe during the squat in healthy people who don’t exceed their lifting capacity.

Squats subject your knees to a high degree of stress, reaching the highest shear peaks between 50-90º (which are the dangerous ones).


Figure XIV. Effects of different degrees of knee flexion on the chondromuscular tension of the knee and the surrounding muscles.

As with the spine, where the forces will depend on the verticality of the torso: the more inclined you are, the greater the shear forces and therefore the higher the risk of injury.


Figure XV. Graphic representation of compressive and shear forces on the spine.

OK, got it! Now, how do I do it?

Let’s differentiate between the different variables that we can control when executing squats.

Correct position of the bar in a squat

There are essentially two ways to hold the bar with a back squat: high or low.

Bar Position

Figure XVI. High bar (left) and low bar (right) position when squatting.

High Bar

When squatting with the “high” position, the bar rests on the trapezius.

This position is predominantly used by people without limitations in their range of motion, allowing the knee moment to be increased (decreasing the hip moment) by requiring less hip flexion for its execution.

Low Bar

On the other hand, the low bar squat requires increased hip flexion to maintain centre of gravity stability over the base of support; decreasing the moment on the knee and increasing that of the hip.

Low Bar VS High Bar Squats

Figure XVII. Differences in body position between a low bar squat and a high bar squat.

It’s difficult to answer definitively which is better, but to summarise: the high bar squat subjects the knees to more compressive forces and the low bar squat subjects the spine to more shear forces. Both are correct ways to squat.

High Bar VS Low Bar

My recommendation is that you do the one you’re most comfortable with. Even still, here are some basic guidelines for choosing one or the other:

FactorConditionPreferred choice
Shoulder mobilityGoodLow bar
BadHigh bar
Risk forKneesLow bar
BackHigh bar
Greater strengthPosterior chainLow bar
Anterior thighHigh bar
MMII mobilityBadLow bar
GoodHigh bar
Torso lengthShortLow bar
LongHigh bar
Leg lengthLongLow bar
ShortHigh bar

Correct hand position for squatting

Your hands can be positioned closer or further away from the centre of the body, extending, flexing, or keeping the wrists in a neutral position. A grip position closer or further away from the sagittal plane will condition the position of the shoulder blades:


Figure XVIII. Open hand position with scapular protraction (top) and closed hand position with scapular retraction (bottom).

It’s important to keep the scapulae adducted as much as possible, i.e. their medial side should be close to the sagittal plane (as if you wanted to hold a pencil between the scapulae).
  • Using a narrow grip inevitably facilitates this position by retracting the scapulae.
  • While a wider grip position protracts the scapulae, making you consciously have to activate the latissimus dorsi of both sides (as well as the rhomboids) to actively depress them.
This is achieved by bringing the arms to the centre of the body, as if you wanted to “scratch your ribs with your elbows”.


Figure XIX. Two different elbow positions depending on the placement of the hands on the bar.

As you can see in the hand position image, closing the grip, “closing your arms” automatically, will make this movement easier (by doing it unconsciously).

Use whatever position you’re most comfortable with, although it’s usually best to employ a closed position; except for very heavy lifters or lifters using a bar in a very low position.

Retracting the scapulas is necessary, as the muscular activation required to maintain this position extends the dorsal section of the spine, preventing you from adopting a hyperkyphotic posture.

Posture Squats

Figure XX. Correct posture and hyperkyphosis posture due to not activating the extensor muscles of the dorsocervical area correctly.

Regarding the positioning of your wrists, it’s really not a very important factor, though it’s preferable to keep them neutral to avoid long-term discomfort.


Figure XXI. 3 different hand placements (dorsal flexion/neura/palmar flexion).

For this, the most suitable position is usually central.

Low bar lifters with little muscle development in the posterior area of the deltoid can benefit from the grip in the third image by internally rotating the shoulders and having more support surface.

If you can’t do any grip other than the one in the first picture… you’re stiffer than a board and you should improve your shoulder mobility – otherwise, it will limit your performance in the medium term.

How to correctly unrack the bar when squatting

The squat bar is positioned on the rack, or the power cage.

Where we place the bar is important, especially as we approach our repetition maximum.

  • An excessively high bar position will cause you to have to flex the soles of your feet to remove it.
  • An excessively low positioning of the bar will mean you have to extend your knees and hips to remove it.

Both set ups will fatigue you before the lift.

It’s best to position the bar at a height that allows you to unrack it from the supports without have to make any strange movements.

How to get into the starting position

There are two steps here:

  1. A first step to take you away from the supports so you don’t crash.
  2. A second step to place the forward foot in line with the placement of the foot of the first step so that it is already in place.


Figure XXII. Unracking the bar.

Once in that position, you can make small adjustments to distribute the load properly and position your feet before starting the movement.

People who use a wider stance need to take a third step, which is to open the stance once the feet are in line; another option is for the first step is to be taken backwards and outwards in one, and for the second to do the same.

This is of relative importance as it’s not a determinant of squat performance, but…

People who take 8 steps to get into position are fatiguing themselves unnecessarily due to lack of experience in setting up.

Stance or “width between the feet”

The stance a lifter should adopt varies greatly depending on a number of factors; and it can range from having your feet together to a width greater than the biacromial breadth (shoulder width).

To the question “how wide should I open my squat support stance?” the answer is: it depends.

Essentially, on what your goal is when performing squats and your anatomy.

If your goal is to develop strength, gain muscle mass, or improve its functionality, the best stance is generally at biacromial breadth, that’s to say, at shoulder width.


Figure XXIII. Two different stance positions associated with the most classic bar placement for each stance.

If, on the other hand, your objective is to lift the maximum possible weight in the lift, you can increase the stance width.

This will limit the ROM you can perform and will also take you to the “limit” of the movement with lower degrees of flexion.

This will allow you to take advantage of the myotatic reflex and overcome the very hard sticking point of the squat at around 90º of knee flexion.

Open stance Squats

Figure XXIV. Greg Nuckols squatting with an open stance and low bar.

Normally, a more open stance tends to be better for more bulky lifters, with less lower-body mobility, with weaker back muscles, and when using a low bar. While the more closed stance favours people with good mobility and who use high bars, such as weightlifters.

Weightlifter squat

Figure XXV. Classic squat position for a weightlifter; closed stance and high bar.

Angle of the feet

Foot placement has always been a subject of debate, as it was said that outward facing feet increased stress on the knee joint and could be more damaging.

We now know that ideally the knees should be bent in line with the direction the foot is pointing, which will normally be rotated 15-20º outwards.


Figure XXVI. Acceptable and unacceptable range of knee-over-foot displacement.

There is an acceptable “range” where the knees can move, but systematically moving out of this range leads to short-term discomfort.

Lifters who use very open stances can rotate their feet even further, reaching 45º.

Very open stance

Figure XXVII. Example of a very open stance with > 20º rotation.

How to breathe while Squatting

There are several breathing techniques to use during the squat, but they all come down to increased intra-abdominal pressure, which is nothing more than a contracting of the core muscles to maintain a stable spine position when lifting.

If your back can’t withstand the transmission of forces, you won’t be able to execute a good squat, so work on your core!

Valsalva Squats

Figure XXVII. Graphic representation and key points of the Valsalva maneuver.

Valsalva Maneuver

The most popular technique is the Valsalva maneuver.

It consists of breathing in during the initial isometric phase, voluntarily closing the airways and increasing the internal air pressure during the eccentric and concentric phases (not breathing out). This raises the diaphragm, contracts the abdomen, and increases pressure on the front surface of the spine.

The air is exhaled in the final isometric phase and the cycle is started again before the next lift.

Youcan learn more about the Valsalva Maneuver in this article.


There are other techniques, such as bracing, that consists of coactivating the musculature of the lumboabdominal belt without restricting ventilation to the same degree as in the Valsalva maneuver, providing the same benefits without affecting blood pressure so intensely.


Figure XXVIII. Example of compression forces when using a brace technique.

Despite being a completely valid and useful technique, it requires training and a high degree of body awareness to be able to execute effectively; so I recommend you practice it first without loads and then gradually incorporate it into your squats.

Correct body tension when performing squats

It’s important that your entire body is under tension.

It’s common to find lifters who don’t activate the pelvic muscles enough, who don’t retract the scapulae, who don’t activate the abdominal muscles adequately

There are a number of tricks for this: one of the most famous is to “break the floor”, trying to externally rotate the feet once they’re supported to activate the muscles that externally rotate the hips to be more stable in the deep squat positions.

Simulated foot movement

Figure XXIX. Graphic representation of simulated foot movement for activation of the external rotators of the hip.

It’s also used to correctly position 3 support points of the plantar arch, which significantly affects squat performance.

Plantar arch

Figure XXX. The 3 support points of the plantar arch.

Make sure to keep the three supports of the above representation in firm contact with the ground so you can push and distribute the force correctly.

Your squat will instantly improve!

A good squat descent

Once we have a good starting position, we begin the descent.

There are two ways to start the movement: sitting “down” or sitting “backwards”. Sitting down is the movement you make when you squat.


Figure XXXI. Kinetics of a “sitting down” squat & Figure XXXII. Kinetics of a “sitting backwards” squat.

Sitting backwards is the movement you make when sitting on a chair.

The relationship is similar to that with the high and low bar:

  • The downwards sitting movement allows you to make a greater range of motion, so it’s more effective for training; the knees go well forward of the toes, although this can be a limitation for people with poor ankle mobility.
  • On the contrary, sitting backwards is more effective for lifters using a low bar, and its purpose is to move as many kilograms as possible in the lift.

Speed of the descent

As long as you’re able to control it, the faster the better.

Less time under tension, less muscle fatigue, and greater effect of the stretching-shortening cycle at the end of the movement to bounce back up like a spring.

You can slow down if your goals are more technical or you’re looking to generate more muscle damage for a specific reason in your training programme.


Figure XXXIII. Graphic representation of the rebound by CEA.

If going down too fast causes you to lose control… Don’t do it.

Squat depth

Squatting depth will depend on your goals.

If you want to lift the maximum possible weight in that lift, go down as far as you want or as far as your federation requires for the movement to be considered valid.

Depth Squats

Figure XXXIV. Classic depth in powerlifting (not enough, invalid movement).

If you’re looking for maximum development in training, go down to the point where your joint mobility no longer allows flexion and “bounce” back up (known as the ATG squat), due to activation of the myotatic reflex.

Weightlifting squat

Figure XXXV. Classic depth in weightlifting.

Greater range of motion translates into more significant improvements in all aspects (strength, hypertrophy, mobility, coordination…).

The less mobility you have, the wider the stance, the lower the bar, and the more you sit back… Less ROM.

Butt Wink, the devil?

Butt wink is the loss of neutrality in the lumbosacral section of the spine at the end of the eccentric phase.

Many lifters fear this position because it destabilises the neutrality of the spine and can increase the risk of injury.

What happens is that people get confused, this isn’t a dangerous butt wink:

Butt Wink

Figure XXXVI. Example of a non-pathological butt wink.

This is a butt wink that can be dangerous in the long run:

Pathological Butt Wink Squats

Figure XXXVII. Example of a pathological butt wink.

  1. The butt wink in the first image is nothing more than the correction of the curvature of the spine in the final phase of maximum flexion.
  2. The butt wink in the image below occurs because of a high tonicity in the psoas iliacus and the hamstring muscles, which produces a retroversion of the hip, caused by a lack of mobility due to poor dorsiflexion.
That’s why the girl in the picture works well up to 90º but from then on she loses neutrality: she needs to improve her ankle mobility to reduce hip flexion and keep her core more vertical.

The ascent

There’s not much to say on the ascent: keep your eyes looking forwards, a neutral position with the cervical curvature of the spine…

Squeeze and move upwards explosively!


Figure XXXVIII. Correct and incorrect position of the neck when squatting.

There’s no point in giving advice as there is none, anything that happens to you at this stage is due to poor positioning, a bad descent, or issues that need to be corrected with compensatory work.

The two most classic scenarios are:

Loss of knee neutrality

When the vastus externus of our quadriceps are weak, our feet are badly positioned, our weight is poorly distributed, or we don’t activate our hip external rotator muscles (gluteus and pelvitrochanteric), genu valgum (knock knees) occurs.

This is the adduction of the knee joint, which places great stress on the connective tissue surrounding the joint and dramatically increases the risk of injury.


Figure XXXIX. Graphic representation of knee valgus.

“Good Morning Squat”

This occurs when our knee extensor musculature is much weaker than our hip extensor musculature, causing the centre of gravity to shift forward, increasing the moment on the hip joint and putting you in a “good morning” position, which increases the risk of vertebral shear injury.

This is known as the Lombard paradox, and you can read more about it here.

Lombard squats

Figure XL. Graphic representation of the Lombard paradox.


Both situations require compensatory work, both muscular and technical, depending on the cause.

How to correctly execute a squat

Bar placementHighLow
Hand placementClosed
Wrist positioningNeutralPalmar flexion
Feet angle15-20º>20º
Support points3 points
Descent speedControlledFast
DepthMaximumMinimum required

Bibliographic Sources

  1. Hartmann, H., Wirth, K., & Klusemann, M. (2013). Analysis of the load on the knee joint and vertebral column with changes in squatting depth and weight load. Sports medicine (Auckland, N.Z.), 43(10), 993–1008.
  2. Nuckols, G. (2020). How to Squat: The Definitive Guide • Stronger by Science.

Related Entries

Review Squats

Technique - 100%

Important points - 100%

Deep squat - 100%

Tips - 100%

Recommendations - 100%

Conclusions - 100%


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About Alfredo Valdés
Alfredo Valdés
He is a specialist in metabolic physiopathology training and in the biomolecular effects of food and physical exercise.
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