Squat (exercise)

A squat is a fundamental strength exercise used to increase the size and strength of lower body muscles.

It also serves as a vital tool for developing core strength. The movement involves a trainee lowering their hips from a standing position and then returning to an upright stance. Because of its effectiveness, the squat is a staple in many recreational exercise programs. It is also one of the three primary lifts in the strength sport of powerlifting. In that sport, the squat is performed alongside the deadlift and the bench press.

The mechanics of a squat involve a specific sequence of joint movements. The exercise begins from a standing position. To initiate the movement, the lifter moves their hips back and bends the knees and hips. This action lowers the torso and any weight being carried. During this descent, the hip and knee joints undergo flexion. Simultaneously, the ankle joint undergoes dorsiflexion, which is the movement of the foot toward the shin. To return to the upright position, the hip and knee joints extend. At this stage, the ankle joint undergoes plantarflexion.

Several muscle groups work together to complete the movement. The primary agonist muscles, which are the muscles primarily responsible for the movement, include the quadriceps femoris, the adductor magnus, and the gluteus maximus. The squat also requires isometric use of the erector spinae and the abdominal muscles. These muscles work to stabilize the body. During the descent, the muscles around the joints contract eccentrically. This means they lengthen while under tension to control the weight. At the bottom of the movement, the muscles reach maximal contraction. This contraction helps to slow and eventually reverse the descent. As the lifter stands up, the muscles contract concentrically to drive the body upward.

Lifters can perform squats at different depths, which changes the nature of the exercise. The competition standard in organized powerlifting requires the crease of the hip to fall below the top of the knee. This is often called "parallel" depth. Squatting below this point is known as a full or deep squat. Squatting above this point is considered a shallow squat. There are other definitions for parallel depth used by some, such as having the femur parallel to the floor. While deep squats change the forces on the knee, making the relative safety of deep versus shallow squats difficult to determine, they are a common goal. High flexion in the knee can increase compressive forces on the menisci and articular cartilages.

There are many ways to hold the weight, which creates different variations of the squat. In a barbell back squat, the bar is placed on the upper trapezius muscle, known as a high bar squat. Alternatively, it can be held lower across the rear deltoids, which is a low bar squat.

Lifters often use a barbell pad to prevent the steel bar from pressing directly against the spine. In a front squat, the barbell is held across the clavicles and deltoids.

This variation also engages the muscles of the upper back, such as the trapezius. Other variations include the sumo squat, where the feet are placed wider than shoulder width, and the box squat, where the lifter sits on a bench at the bottom of the movement.

Historically, certain squats have been named after specific people or traditions. The Zercher squat is named after the 1930s strongman Ed Zercher and involves holding the bar in the crooks of the arms.

The Steinborn squat is named after Henry "Milo" Steinborn and is performed without a rack by lifting the bar from the floor to the back. The hack squat has roots in Germany, where it was once known as "Hacke." This name likely comes from the way Prussian soldiers clicked their heels together. This version was popularized in English-speaking countries by the wrestler George Hackenschmidt.

Advanced training often involves specialized equipment to alter the difficulty or safety of the lift. A power cage can be used to reduce the risk of injury. Some lifters use variable resistance squats by attaching chains or elastic bands to the barbell. This changes the resistance at different phases of the movement. For example, bands can reduce resistance in the lower, weaker phase to help a lifter overcome a "sticking" point.

Additionally, single leg squats, or unilateral squats, can be used to improve balance and address muscle imbalances. In a single leg squat, the weight required is significantly less; for an 80 kg lifter, lifting 40 kg on one leg is equivalent to lifting 160 kg with two legs.