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).

Figure I. Deep back squat.

Fundamentals of the squat as a movement

Biomechanics

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.

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.

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.

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

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

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

Performed in sequence, this is the complete movement:

Figure VI. Kinematics of a front squat with dumbbells.

Load

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).

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

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

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

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.

Ankles

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.

Figure VIII. Examples of different dorsiflexion ranges.

Knees

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

• Quadriceps

Figure IX. Example of knee extension through quadricep action.

Hips

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

• Hamstrings.
• Gluteus maximus.
• Adductors.

Figure X. Example of hip extension.

Spine

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

• Spinal erectors.

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:

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.

Core

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.

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.

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…

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?

Correct position of the bar in a squat

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

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.

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

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).

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.

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.

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.

Both set ups will fatigue you before the lift.

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…

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.

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.

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.

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.

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.

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.

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.

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.

Bracing

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.

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…

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.

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

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:

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.

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.

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.

Figure XXXV. Classic depth in weightlifting.

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:

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

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

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.

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.

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.

Figure XL. Graphic representation of the Lombard paradox.

How to correctly execute a squat

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.

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