How to Perform the Squat

By Tony Boutagy

The squat is widely regarded as the king of the lower body strength exercises. There is no other equivalent in the gym that can develop flexibility, strength, activation of muscle tissue and hormonal response as well as the squat, or its derivatives. As with any advanced exercise, the correct technique is vital to getting the most out of the exercise and minimizing the risk of injury. Here is how a back barbell squat should be performed correctly.

Set up:

Set a barbell on the upper portion of the trapezius.
Grip the barbell as close as possible to the outside of the shoulders and tuck the elbows in and under the bar. Maintain this position throughout the movement, as it keeps the load as close as possible the centre of mass.
Elevate the chin slightly.
Set the feet hips width apart and turn the toes out 15 degrees.

Descent:

The knees first move directly forward as far as possible.
After the knee initiates the movement, the hips lower down as low as flexibility allows.
Keep the back as erect as possible with the chest up.
The body is lowered under control until the hamstrings make contact with the calves.
The knees should travel forward over the toes.
The heel should remain flat on the floor.

Ascent:

The hips and knees extend together to bring the body back to the starting position.
Keep the torso as upright as possible throughout the ascent.

The fitness industry, like most professions, has fads come and go and flavours of the month. A squat performed only through partial range is one of those ill conceived exercises, much like performing strength exercises while kneeling or standing on a Swiss ball, which most strength experts wished left the gym as quickly as they became popular.

There are two primary reasons why partial squatting has become the norm in the fitness industry – and I say fitness industry, because in strength and conditioning circles, a squat is not a squat unless you go all the way down. The first is that most people do not possess the flexibility and strength to be able to perform the exercise through the full range of motion, so rather than developing the appropriate prerequisite abilities, they resort to the half squat instead. The second reason is because most trainers are taught that you should never squat deeper than thighs parallel to the floor or to let the knee travel past the toes.

This concept is so commonly known and accepted, but I am still yet to see any scientific evidence at all that provides proof that performing the squat through a full range of motion with correct technique is dangerous to the knees. The evidence simply does not support such a viewpoint. At any rate, we would know if full squatting was dangerous to the knees well before the scientific community told us because every athlete that trains for the sport of weightlifting – which involves ballistic deep squatting with very heavy loads – would be in rehab for their knees! Additionally every Asian or baby who sits for prolonged periods in a deep squat position would be lining up for knee replacements. I have yet to see an obstetrician treat the newly born baby for patellofemoral pain on birth, which, according to some, should happen given that humans spend the first few months from conception living in a deep squat position in their mother’s womb! And if the knee shouldn’t travel forward of the toes, then walking up stairs would be extremely difficult!

A study by Salem & Powers (2001) looked at patellofemoral joint kinetics at three different depths of knee flexion: 70 degrees (above parallel), 90 degrees (at parallel), and 110 degrees (below parallel). The researchers discovered that ‘peak knee extensor moment, patellofemoral joint reaction force and patellofemoral joint stress did not vary significantly between the three squatting trials’. This study did not find any evidence that squatting through full range of motion increased stress on the patellofemoral joint. A recent review by Comfort & Kasim (2007) had the exact same conclusions. Despite these reasons, I never ceased to be amazed that such a myth can still be taught to personal trainers despite there being no evidence whatsoever to validate the belief.

The way I see it, if a trainee cannot perform a full squat, they are considered to be in the rehabilitative stage of training. This is because a full squat that is performed correctly indicates structural muscular balance in the lower limbs and sufficient flexibility of the ankles, knees and hips. If a trainee cannot perform a full squat with correct technique, specific flexibility and special exercises, such as split squats and step up variations, will be recommended to address the imbalances that prevent the client from full squatting.

The correct way to perform any squatting variation (back, front, dumbbell, or overhead) is to take the three working joints – the hip, knee & ankle – through their fullest range of motion. The lowest position is where the hamstrings make full contact with calves. This keeps the knee joint healthy and lubricated, improves knee stability, mobilizes the soft tissue and activates the available musculature fully. In the terminal range, the knee will be brought forward past the toes and full contact is made between the hamstrings and calves. This complete range of motion refreshes the joint with synovial fluid (via synovial flushing), recruits the available musculature and aids flexibility development.

Stopping the squat prematurely, for example, parallel or higher, or restricting the knees from traveling forward, causes a change in motion half way through an eccentric loading cycle and creates uneven distribution of muscle and joint forces. The position of most instability for the knee joint is 90 degrees. This is why trained sports physicians assess knee stability using the Drawer Test at 90 degrees knee flexion, and not in the deep squat position. The knee is highly stable at full extension and full flexion. Despite what is commonly thought in gyms, it is highly dangerous and contributes to destabilized knees, poor VMO development, over-developed vastus intermedius, inadequately recruited hamstring and gluteaus maximus, and incorrect joint tracking over the long term when one performs partial range squats.

Joints are designed to load and de-load, and for optimal lumbopelvic mechanics, the sacroiliac joint must tilt back and forth in a process called nutation and counternutation. Lack of mobility at the SI joint has been linked to low back pain. The deep squat position allows the SI joint to nutate and counternutate, keeping the SI mobile and healthy and activates the deep hip stabilizers, such as the piriformis, gemelii, obturators and the quadratus. All this is precisely what happens when the hamstrings make contact with the calves in the lowest position. This creates longevity in the joints, despite what is commonly taught to personal trainers.

There is much scientific support for the superiority of the full squat over a partial-range squat. For example, data from Sweden which has shown that the best predictor of knee injury is inadequate ankle flexibility. Put another way, athletes who could not perform a full squat had the highest incidence of knee injury. Swiss research has demonstrated that those athletes who could perform a full-range overhead squat suffered the least amount of knee injuries, groin strains and hamstring pulls. A study by Wilson et al. (1989) found that weightlifters had the best knee stability of athletes and non-athletes tested. The common feature of the three investigations was full squatting.

The obvious considerations to this ROM are injury history, painful knees (due to a variety of reasons from structural damage to tightness) and severe lack of mobility from the cervical spine down to the ankles. The primary point is this: if you cannot perform a full squat, you should not perform a squatting exercise at all. Split squatting and step up variations must be used until a full squat can be performed correctly with no pain. Again, despite what personal trainers have been taught by well-intentioned educators and physiotherapists, a half squat should never be used and the trainee should always be advised to take the knee forward during the movement rather than attempting to sit back and restrict forward knee movement. Research from Andrew Fry’s group showed that not allowing the knee to travel forward during squatting actually increased low back joint loading by over ten-fold! (Fry et al. 2003).

Functional anatomy:

During the concentric phase of the squat, both the knees and hips extend. The muscles that extend the knee are the quadriceps femoris (vastus medialis, lateralis and intermedius and the rectus femoris). The muscles that extend the hip are the gluteus maximus, semitendinosus, semimembranosus, the long head of the biceps femoris, and the posterior fibers of the adductor magnus. EMG and MRI research has shown that a full squat also recruits the stabilizing muscles of the ankle, knee and hip. Interesting, the range of motion of a squat makes a considerable difference as to which muscles are needed to contribute to joint movement. Caterisano et al. (2002) found that for the hamstring and gluteaus maximus muscle to be sufficiently recruited during a squat, a full squat depth was needed. Stopping the range of motion at parallel, or above, recruited those muscles very poorly. This uneven recruitment of thigh muscles, in part, explains why it is dangerous in the long term for joint health to perform a partial range squat.

Things to watch for:

Making sure the knee comes forward past the toes.
Correct knee tracking.
Maintaining the heel flat on the floor.
Lowering under control.
The lowest range of motion is the most potentially dangerous. A trainee must never bounce out of the bottom position, but rather exert special control in this phase of the lift.
If a trainee’s back round out before the thighs are parallel to the floor, that person is not qualified to perform a squat and should focus on other lower limb variation.
If a trainee’s back round out after the thighs are parallel to the floor, that person is qualified to squat and should be encouraged to squat even if the pelvis rolls under. This is a perfectly natural part of spinal movement during squatting.

Variations:

To change the resistance curve of the full squat, you can hold a dumbbell in each hand, position the bar on the deltoids or hold a bar at arms length above the head. One variation is not better than another, despite what some strength coaches say about the superiority of the front squat. All forms of the squat have their place in the overall conditioning of a client. They each have their advantages and disadvantages and should be periodized according to the client’s needs.
Destabilization training has its place in general preparatory training and in rehabilitation, but training on an unstable surface (wobble board, Swiss ball, BOSU etc) may alter and slow down the muscle activation patterns, leaving you more vulnerable to injury and reduced performance (Stone et al. 2007). Furthermore, destabilizing the movement forces you to lift less load, reducing the activity of the prime movers.