Squats, along with deadlifts, are some of the best compound exercises for the upper and lower body. Squat varieties differ based on the stance, width, bar placement, and squat depth.
A deep squat requires conditioning and training because not all individuals have the physiology that permits a full, deep squat. An individual can perform deep squats only as low as the exercise form permits at any given time. Squat depth will increase over time as the muscles and joints increase in both strength and mobility.
This article will discuss the benefits of deep squats and the factors affecting squat depth. It will also clarify some of the notions and misconceptions surrounding this concept.
What is a "Deep Squat"?
The common recommendation for squat form is maintaining a shoulder-width distance between the feet. It is also recommended to keep the crease of the hip along the knee line. This is referred to as a parallel squat.
A deep or full squat goes beyond parallel and goes into dorsiflexion of the ankle. Essentially, as soon as the crease of the hip is below the height of the knees (below parallel) you are deep squatting.
Muscle Engagement from Full Squatting
The main reason people increase squat depth is because doing so engages major joints of the lower body: hips, knees, and ankles. Full squats also engage the lower posterior chain better, primarily the glutes and adductors.
Two studies of squat depth help to validate these claims:
The first was published in 2013 and had 17 men perform barbell squats three times per week over a 12 week period.
These 17 men were divided into two groups:
- First Group: Trained full squats (120 degree knee flexion)
- Second Group: Trained quarter squats (60 degree knee flexion)
The muscle growth in the full squat group was significantly greater than the quarter squat group.
In the second study, a group of 10 men trained barbell squats twice a week for 10 weeks.
These 10 men were divided into two groups:
- First Group: Trained Full Squats (140 degree knee flexion)
- Second Group: Trained Half Squats (90 degree knee flexion)
An MRI was used to analyze the muscle volume of the quadriceps, hamstrings, gluteal muscles, and adductors.
The full squats saw greater muscle growth than the half squats in the glutes and adductors.
It's worth noting that in both studies, both groups experienced similar growth in their quadriceps. Where-as neither saw growth in their hamstrings.
This tells us that barbell squatting primarily utilizes the quadriceps and increasing squat depth results in greater gluteal and adductor activation.
Factors Affecting Squat Depth
The depth at which you squat requires certain biomechanical aspects. These biomechanical aspects are often a factor of physiological features that either permit or inhibit people from performing a full squat in perfect form. The most prominent physiological feature is leg length.
Leg length directly affects the depth of the squat. People with long legs have to exert greater effort in performing squats because of the greater range of motion required to complete the movement. It also affects their biomechanics; The tendency to lean forward to balance his/her weight when squatting.
Another physiological factor that can affect squat performance is the hip socket. The hip socket is the point where the pelvic socket and the femur head meet. This socket is different for every individual; Some people have a deep hip socket, while others have a shallow hip socket.
A deep hip socket, referred to as Celtic hip, is best for rotational movements but can become burdensome and painful when performing deep squats. A shallow hip socket, on the other hand, can accommodate deep squats well without any pain at any level of the exercise.
Thus, for people with deep hip sockets, performing deep squats can also become dangerous because of the possible abrasion between the femur head and the pelvic socket.
Other lower body joints that can affect squat depth are the hip, knees, and ankles. Weak lower body joints can lead to compensatory movements, which can lead to lower back injuries.
Compensatory movements occur involuntarily when the major muscles and joints that are responsible for performing said movement become overburdened due to lack of strength and flexibility and require help from other supportive muscles and joints on the body. This can ultimately lead to transferring the burden of the squat onto the lower back, which is sub-optimal and can become a cause for lower back injury.
A form of compensatory movement includes "buttwink" or pelvic dumping which occurs due to inflexible hips.
Heels moving upwards and excessive forward lean are also forms of compensatory movement that are a result of weak calves or ankles and weak quadriceps muscles, respectively.
Common Misconceptions About Deep Squats
It is a common misconception that full deep squats can increase the risk for knee injury because it increases the pressure on the knee extensor and ligaments including the ACL and the PCL. There is little evidence to prove that deep squats can increase knee injuries, especially among Olympic lifters who do full deep squats when performing clean-and-jerk and snatches.
According to G. J. Salem and C. M. Powers of the Department of Biokinesiology and Physical Therapy of the University of Southern California, performing parallel and deep squats made no significant difference in their impact on the knees. M. E. Steiner and W. A. Grana also wrote in the American Journal of Sports Medicine that the deep squat can increase knee stability.
In terms of the pressure on the knee ligaments, the research also showed that the ACL and PCL endured more pressure during parallel squats. Other research also showed that parallel squats have the highest compressive force on the knees and performing squats beyond the knee help to relieve pressure.
Dr. Rafael Escamilla is a professor on Physical Therapy at California State University and his study on knee biomechanics showed that parallel squats are best for engaging the quadricep muscles. He also wrote that increased squat depth can provide several benefits for muscle and strength gains but also comes with a risk for back injuries.
Furthermore, it is also perceived that deep squatting can cause more muscular imbalances than parallel squats because of its greater engagement of the rectus femoris over the posterior chain of the lower body. Glute activation is at its peak during parallel squats and diminishes as the crease of the hips exceed below the knee line. However, other research has shown that deep squats engage the glute muscles up to 25% more compared with parallel squats while retaining the engagement of the hamstring muscles.
Full squats involve greater recruitment of joints and muscles as compared with parallel squats due to the increased range of motion. Despite its pressure relief on the knees, insufficient strength in the joints and muscles can result in compensatory movements that can compromise on form leading to the diminished natural curvature of the spine.
Thus, deep squats may provide a marginal increase in lower body muscular engagement but it also comes with increased risk for back injury. In terms of weighing the risk and benefits, squatting slightly below parallel is best for providing the maximal activation of the glutes to reach hypertrophy while minimizing the harm on the knees and back.
How Low Should You Squat?
A deep squat is not necessarily the best squat variety for all people. Due to the various factors that affect squat performance such as mobility, strength, and physiology, the benefits of greater depth vary on an individual basis.
Deep squats are therefore not the only form of squats that will provide significant benefits for muscle growth and strength gain. Finding the best squat stance, bar placement, volume, and frequency that is most appropriate is therefore individualized.
Depth is not the most important factor in terms of effectiveness. Performing deep squats that are not suitable for an individual's musculature, features, and physiology can cause discomfort and inhibit the overarching benefits of the exercise.
It is important to remember to avoid stretching the squat to the point that the exercise becomes painful. This is usually a sign that certain aspects of the squat are inefficient, leading to compromises in form.
Deep squats provide significant benefits for promoting growth in muscle size, strength, and stability. However, it also comes with significant risks on the lower back, especially for individuals who do not possess the necessary muscle and joint strength and endurance to perform full squats with optimal form.
Thus, it is best to listen to the body and only perform squats as deep as your squatting form permits.