Squat (exercise)


A squat is a strength exercise in which the trainee lowers their hips from a standing position and then stands back up. During the descent, the hip and knee joints flex while the ankle joint dorsiflexes; conversely the hip and knee joints extend and the ankle joint plantarflexes when standing up.
Squats are considered a vital exercise for increasing the strength and size of the lower body muscles as well as developing core strength. The primary agonist muscles used during the squat are the quadriceps femoris, the adductor magnus, and the gluteus maximus. The squat also isometrically uses the erector spinae and the abdominal muscles, among others.
The squat is one of the three lifts in the strength sport of powerlifting, together with the deadlift and the bench press. It is also considered a staple exercise in many popular recreational exercise programs.

Form

The squat begins from a standing position. The squatting movement is initiated by moving the hips back and bending the knees and hips to lower the torso and accompanying weight, then returning to the upright position.
Weight is often added and is typically in the form of a loaded barbell. Dumbbells and kettlebells may also be used. When a barbell is used, it may be braced across the upper trapezius muscle, which is termed a high bar squat, or held lower across the back and rear deltoids, termed a low bar squat. Various torso bracing techniques are used wherever the bar is placed on the back to prevent direct contact with the spine, which can cause pain and injury. This can be a problem for new squatters who squat in a high bar style as they may not have enough muscle mass to form a cushion for the bar and prevent it from applying pressure directly to their spine.
Squats can be performed to varying depths. The competition standard is for the crease of the hip to fall below the top of the knee; this is colloquially known as "parallel" depth. Although it may be confusing, many other definitions for "parallel" depth abound, none of which represents the standard in organized powerlifting. From shallowest to deepest, these other standards are: bottom of hamstring parallel to the ground; the hip joint itself below the top of the knee, or femur parallel to the floor; and the top of the upper thigh below the top of the knee. Squatting below parallel is considered a full or deep squat, while squatting above it qualifies as shallow. Though the forces on the ACL and PCL decrease at high flexion, compressive forces on the menisci and articular cartilages in the knee peak at these same high angles. This makes the relative safety of deep versus shallow squats difficult to determine.
As the body descends, the hips and knees undergo flexion, the ankle extends and muscles around the joint contract eccentrically, reaching maximal contraction at the bottom of the movement while slowing and reversing descent. The muscles around the hips provide the power out of the bottom. If the knees slide forward or cave in then tension is taken from the hamstrings, hindering power on the ascent. Returning to vertical contracts the muscles concentrically, and the hips and knees undergo extension while the ankle plantarflexes.
Common errors of squat form include descending too rapidly and flexing the torso too far forward. Rapid descent risks being unable to complete the lift or causing injury. This occurs when the descent causes the brace to relax and tightness at the bottom is lost as a result. Over-flexing the torso greatly increases the forces exerted on the lower back, risking a spinal disc herniation. Another error is when the knee is not aligned with the direction of the toes, entering a valgus position, which can adversely stress the knee joint. An additional common error is the raising of heels off the floor, which reduces the contribution of the gluteus muscles.

Muscles used

Agonist muscles
Stabilizing muscles
Various types of equipment can be used to perform squats.
A power cage can be used to reduce risk of injury and eliminate the need for a spotting partner. By putting the bar on a track, the Smith machine reduces the role of hip movement in the squat and in this sense resembles a leg press. The monolift rack allows an athlete to perform a squat without having to unrack and step out of the rack.
Other equipment used can include weight lifting belts, which allow the athlete to achieve higher intra-abdominal pressure, and heeled shoes or shoe inserts which allow for a deeper squat. Wrist straps are another piece of recommended equipment; they support the wrist and help to keep it in a straightened position. They should be wrapped around the wrist, above and below the joint, thus limiting movement of the joint. Heel wedges and related equipment are discouraged by some as they are thought to worsen form over the long term.
Chains and thick elastic bands can be attached to either end of the barbell in order to vary resistance at different phases of the movement. This may be done to increase resistance in the stronger upper phase of the movement, in order to make the difficulty more consistent throughout the movement. Bands can also be used to reduce resistance in the lower, weaker phase by being hung from a power rack and the barbell being increasingly supported by them as it is lowered. This can help someone to overcome a 'sticking' point. A squat performed using these techniques is called a [|variable resistance squat].

Variants

The squat has a number of variants, some of which can be combined:

Barbell

  • Back squat – the bar is held on the back of the body upon the upper trapezius muscle, near to the base of the neck. Alternatively, it may be held lower across the upper back and rear deltoids. In powerlifting the barbell is often held in a lower position in order to create a lever advantage, while in weightlifting it is often held in a higher position which produces a posture closer to that of the clean and jerk. These variations are called low bar and high bar, respectively.
  • *Sumo squat – A variation of the back squat where the feet are placed slightly wider than shoulder width apart and the feet pointed outwards.
  • *Box squat – at the bottom of the motion the squatter will sit down on a bench or other type of support then rise again. The box squat is commonly utilized by powerlifters to train the squat.
  • Front squat – the barbell is held in front of the body across the clavicles and deltoids in either a clean grip, as is used in weightlifting, or with the arms crossed and hands placed on top of the barbell. In addition to the muscles used in the back squat, the front squat also uses muscles of the upper back such as the trapezius to support the bar.
  • Hack squat – the barbell is held in the hands just behind the legs; this exercise was first known as Hacke in Germany. According to European strength sports expert and Germanist Emmanuel Legeard this name was derived from the original form of the exercise where the heels were joined. The hack squat was thus a squat performed the way Prussian soldiers used to click their heels. The hack squat was popularized in the English-speaking countries by early 1900s wrestler George Hackenschmidt. It is also called a rear deadlift. It is different from the hack squat performed with the use of a squat machine.
  • Overhead squat – the barbell is held overhead in a wide-arm snatch grip; however, it is also possible to use a closer grip if balance allows.
  • Zercher squat – the barbell is held in the crooks of the arms, on the inside of the elbow. One method of performing this is to deadlift the barbell, hold it against the thighs, squat into the lower portion of the squat, and then hold the bar on the thighs as you position the crook of your arm under the bar and then stand up. This sequence is reversed once the desired number of repetitions has been performed. Named after Ed Zercher, a 1930s strongman.
  • Steinborn squat – named after the traditional strongman Henry 'Milo' Steinborn, and performed without a rack, the barbell begins on the floor. The lifter picks up one end, and lifts until it's nearly vertical, before bending to position it against their back, as if in a back squat. They then lower their hips, allowing the top of the bar to lower until the bar is straight across their back, with their body in the bottom of a squat. Normal back squats can be performed from this position.
  • Deep knee bend on toes – it is similar to a normal back squat only the lifter is positioned on their forefeet and toes, with their heels raised, throughout the repetition. Usually, the weight used is not more than moderate in comparison to a flat footed, heavy back squat.
  • Single leg squat - The single leg squat, also known as a unilateral squat, involves squatting with one leg instead of two. Usually the leg which is held off the ground moves behind the person as they squat, but alternatively the person may position it ahead of themselves. Bilateral split squats which significantly increase the work performed by the front leg are sometimes erroneously referred to as single leg squats due to this emphasis. Single leg squats can be used to strengthen a person's stabilizer muscles more so than two legged squats and improve their ability to balance. They can also be used to remove muscle imbalances in the body by ensuring that, when performed alternatively, the right and left leg do the same amount of work. In comparison to two footed squats, the barbell weight only needs to be half of what it would be, minus the lifter's weight for the legs to perform the same amount of work i.e. for an 80 kg lifter, lifting 40 kg using only the left leg, means the left leg is lifting the equivalent of what it does in a two footed squat with 160 kg. This means that the single leg squat can be used in rehabilitation programmes where there is a need to avoid heavier loading of the back.
  • Loaded squat jump – the barbell is positioned similarly to a back squat. The exerciser squats down, before moving upwards into a jump, and then landing in approximately the same position. The loaded squat jump is a form of loaded plyometric exercise used to increase explosive power. Variations of this exercise may involve the use of a trap bar or dumbbells.
  • Variable resistance squat – In keeping with variable resistance training in general, a variable resistance squat involves altering the resistance during the movement in order that it better matches, in percentage terms, the respective 1RM for each strength phase the person is moving through i.e. more resistance in the higher stronger phase and less in the weaker lower phase e.g. 60 kg in the lower phase and 90 kg in the higher phase. Such an alteration of resistance can be achieved by the use of heavy chains which are attached to either end of the barbell. The chains are gradually lifted from the floor as the barbell is raised and vice versa when it is lowered. Thick elastic bands which are more stretched in the higher phase and less stretched in the lower phase can also be used. Combining heavier partial reps with lighter full reps can also help to train the stronger and weaker phases of the movement so the percentage of 1RM lifted for each phase respectively is more similar. Training with variable resistance squats is a technique used to increase speed and explosive power.
  • Partial rep – Partial rep squats only move through a partial range of movement when compared with full squats which move through a full range of movement. Full range for a squat usually means the higher stronger phase of a squat's strength phase sequence, but may also refer to just squatting for the lower weaker phase. When partial squats are used to strengthen the higher ROM this usually involves significantly increasing the weight in comparison to the weight used for a full squat. The percentage lifted of the stronger higher phase's 1RM can therefore be increased and not limited by the requirement to move through the weaker lower range of movement e.g. a person lifts 100% of his 1RM for the higher stronger phase which is 150 kg. If he did a full squat he would only have been able to do about 66% of his stronger phases 1RM because his 1RM for a full squat, including the weaker lower phase, is 100 kg. Training with heavier partial squats can help to improve general strength and power. It can also be more beneficial for sports and athletics as that ROM is more likely to be required in those activities i.e. it is rare to need to perform a full squat in sport, whereas partial squatting happens frequently. Partial squatting with a heavier weight than a full squat allows for can also help to improve a person's 1RM for a full squat. When partial squatting only the lower phase this is usually to strengthen that relatively weak phase of the lift in order to overcome a sticking point i.e. a point a person gets "stuck" at and finds it difficult to progress past. It is commonly recommended that partial squats are best used in conjunction with full squats.