Barbell Squat: Benefits, Muscles Used, and More

published by: Debbie Luna
Last Updated:
June 1, 2022

The cornerstone of many strength building or bodybuilding training programs, the barbell squat is referred to as the “king of lifts” due to its highly effective method of inducing training stimulus, as well as being one of the best lower body exercises possible.

With such a reputation, it is important for the exerciser to understand what exactly makes the barbell squat so special - and how they may utilize this particular lift in order to improve their workout sessions and achieve their goals.

The barbell squat is, as its name implies, a lower body compound exercise that utilizes a barbell; making its stimulus that of a free weight nature. 

Due to its accessibility and effectiveness, the barbell squat may be utilized in a variety of ways and methods that make it a near-essential in practically any training routine, so long as it is performed in the correct manner.

What is the Barbell Squat?

In more technical terms, the barbell squat is a closed kinetic chain compound movement with a targeted rate of perceived exertion (or RPE) anywhere between 5 and 10 on the modified borg’s scale.

barbell full squat

In terms of functionality, the barbell squat is considered to be one of the most critical movements in the development of athletic capacity, lower body strength, central nervous system adaptation and reduction of injury risk in certain capacities.

This is all in connection to the fact that the barbell squat at its core is a direct mimicry of one of the most basic movements of the human body, with additional resistance being added to such a movement serving to improve the function of said body in totality.

Why is the Barbell Squat So Common?

The barbell squat is considered a resistance training fundamental movement because of its efficiency and wide range of muscle groups activated to a significant extent; thereby resulting in greatly improved caloric expenditure, muscle group stimulus and time saved by the exerciser, as they no longer need to perform multiple leg exercises consecutively instead.

In terms of advanced athletic training or physical rehabilitation, analysis of the standard barbell squat can reveal deficits in an individual’s basic biomechanics or training regimen, with certain missed form cues or improper exercise mechanics pointing towards a muscle group imbalance or similar physical dysfunction.

As such, not only does the barbell squat act as an excellent tool for building lower body mass, stability and strength - but also as a method of ensuring that the exerciser or patient is having their needs and goals met by their prescribed exercise routine.

Due to its usage of a barbell, the barbell squat is also an excellent method of inducing progressive overload in the various muscles targeted through its performance, as micro-loading of plates or the usage of additional repetitions is rather difficult to achieve with other leg exercises meant to induce progressive overload.

What Muscles are Worked by the Barbell Squat?

Being among one of the most famous compound exercises, the barbell squat is capable of working a variety of muscle groups in varying capacities and intensities, with muscle groups undergoing more intense muscle group activation being dubbed primary mover muscles as they provide a larger amount of the force required to perform the exercise.

high bar squat

Succeeding muscle groups that are contracted in a dynamic capacity and otherwise aid in the performance of the primary mover muscles are also called secondary mover muscles; of which do not provide as much force as the primary mover muscles, but nonetheless are vital to the proper performance of the exercise.

Other muscle groups involved in the exercise in a synergistic or coactivating capacity so as to stabilize joints and the source of resistance are otherwise referred to as stabilizer muscle groups.

Primary Mover/Agonist Muscles

The barbell squat makes great use of the quadriceps femoris and hamstring muscle groups throughout the entirety of the exercise, with the gluteus muscle group also taking the role of a primary mover muscle if the depth of the squat is sufficiently low enough.

For the most part, exercisers following the standard foot width and whom are of ordinary mobility capabilities will activate the quadriceps femoris to the greatest extent among all other stimulated muscle groups - as it is the quadriceps femoris that is responsible for the majority of the movement throughout both phases of the repetition.

Secondary Mover/Agonist Muscles

Though not as effective at force output or recruited as intensely as the primary mover muscles, the secondary mover muscles involved in the barbell squat are constituted by the hip flexors, the various smaller muscles of the calves that are stretched during the bottom of the repetition, and the lower back muscles that maintain a neutral spinal curve.

The secondary mover muscles may also be occasionally utilized as stabilizer muscle groups during small portions of the barbell squat’s form, contracting them not only in a dynamic capacity but also in a static one.

Stabilizer Muscle Groups

Primarily responsible for ensuring the exerciser’s joints remain stable and that the weight is kept in a secure manner so the primary mover muscles may output force more efficiently, the stabilizer muscle groups of the erector spinae, abdominals, obliques (and calves to an extent) are all contracted in an isometric manner throughout each repetition.

Only small amounts of clinical evidence point towards stabilizer muscle groups undergoing muscular hypertrophy in any significant amount - though that is not to say that said stabilizer muscle groups are not otherwise developed in other manners, such as in the very capacity to act as a stabilizer muscle itself.

Benefits of the Barbell Squat

The barbell squat is, among other things, an exercise capable of imparting certain benefits that are otherwise difficult to achieve with the usage of other lower body exercises. 

This is most noticeable in the ability of the barbell squat to impart skeletal muscle development, burn fat and build strength to such an effective level that it easily outpaces many other exercises of its type -  among other benefits that are characteristic of the barbell squat’s nature as a resistance exercise.

One of the Most Effective Lower Body Exercises

Among the many leg muscle compound movements, few are as effective as the conventional barbell squat - both due to the fact that it conforms quite well with the natural biomechanics of the human body, but also due to its capacity to recruit muscle fibers in many of the largest muscle groups located in the lower body.

full squat side view

This will not only result in a significant increase in size and strength, but also muscular control and stability - aiding all sorts of exercisers in reaching their training goals, be it a return to ordinary physiological function from an injury or maximizing an athlete’s jump height.

Significant Caloric Expenditure

With such a wide range of muscle groups being activated to a high intensity, it is no surprise that the barbell squat is capable of burning fat at a rapid pace via significant caloric expenditure - a factor that is also aided by the increased heart rate of the high exertion normally involved in a set of barbell squats.

Exercisers wishing to significantly increase the amount of calories they burn during a workout may find that performing barbell squats at higher levels of volume per set can help them in reaching their goal.

Athletic Ability Improvements

The barbell squat is a mainstay of not only strength-based athlete training programs, but also in practically every other form of training program specifically meant to improve the athletic prowess of an individual in their given sport.

For sprinters wishing to improve their top speed, basketball players seeking to increase their jump height, or powerlifters training for their next meet; the barbell squat likely will play a central role in improving such physical capacities.

Form Cues and Mechanics of the Barbell Squat

One of the most common mistakes novice exercisers make when performing a barbell squat is that of knee valgus, wherein the knees will bend inwards during the concentric portion of the exercise. This can easily lead to patella dislocation, a loss of balance, or torn connective tissues if performed repeatedly.

squat incorrect knees

In connection to improper knee rotation, improper spinal curve such as rounding at the upper back or shoulders can lead to severe injury, requiring that the exerciser retain a braced core and neutral spine position throughout each repetition of the barbell squat as well.

During the eccentric or first phrase of the barbell squat, it is also important for the exerciser to ensure that both their hips and knees lower simultaneously, as one set of joints bending before the other will not only affect their form, but place unneeded and excessive stress on said joints.

squat hips too high

So as to recap; the main form cues and mechanics involved in the barbell squat are proper external knee rotation, retaining a braced core and neutral spine, as well as ensuring that the hips and knees move simultaneously so as to avoid injury.

Quite a few other form cues are present in the barbell squat that are equally as important - however, these aforementioned points are the most important, as they directly concern the exerciser’s risk of injury during the exercise.

How to Program the Barbell Squat

In the majority of training programs, the barbell squat acts in a central role, being responsible for the majority of the lower body training stimulus in each workout session.

While this is not always the case, the barbell squat is generally programmed with lower amounts of volume and higher levels of resistance for the purposes of inducing efficient and highly effective training stimulus in practically all leg muscle groups.

In a few instances, however, the barbell squat may instead act as a secondary compound exercise performed with less intensity as other compound movements that also activate the legs are used instead; especially during workout sessions that involve the barbell deadlift and its variants.

Generally, the barbell squat is performed in sets of repetitions between 3 to 20, though the higher end of this range is usually reserved for AMRAP (as many reps as possible) sets or advanced athletic endurance programs.

Common Mistakes to Avoid While Barbell Squatting

Excessive Resistance

Perhaps one of the most common mistakes exercisers make when performing a barbell squat is loading it with more weight than they could handle while maintaining proper form - eventually leading to injury and the development of improper form habits.

Exactly how heavy a repetition of the barbell squat should be will depend on many factors, but it is generally a good rule of thumb to err on the conservative side and to always “leave one rep in the tank” per set.

Lifting of Heels

Among the various form cues that make up a proper barbell squat, the exerciser lifting their heels at the bottom of the repetition is one of the most frequently encountered. Fortunately, it is not a mistake with serious ramifications for the most part.

Nonetheless, it is important for the exerciser to ensure that their heels always remain in contact with the ground so as to ensure that they stay properly balanced, as well as allowing them to achieve a wider range of motion during the exercise.

‘Dive-Bombing’

Another common mistake made by exercisers is allowing their body to descend too rapidly during the first portion of the repetition - thereby affecting their form and placing the knees and lower back at risk of injury as stabilizer muscles are taxed by the greater momentum.

A repetition of the barbell squat should be performed in a slow and controlled manner, with every muscle group being activated thoroughly throughout the entire squat repetition.

References

1. Hagen Hartmann, Klaus Wirth, and Markus Klusemann, ‘Analysis of the Load on the Knee Joint and Vertebral Column with Changes in Squatting Depth and Weight Load’, in Sports Medicine, (2013, Vol.43), pp.993-1008

2. Myer GD, Kushner AM, Brent JL, Schoenfeld BJ, Hugentobler J, Lloyd RS, Vermeil A, Chu DA, Harbin J, McGill SM. The back squat: A proposed assessment of functional deficits and technical factors that limit performance. Strength Cond J. 2014 Dec 1;36(6):4-27. doi: 10.1519/SSC.0000000000000103. PMID: 25506270; PMCID: PMC4262933.

3. Lucero, Rhys AJ, Andrew C Fry, Christopher D LeRoux, and Matthew J Hermes. “Relationships between Barbell Squat Strength and Weightlifting Performance.” International Journal of Sports Science & Coaching 14, no. 4 (August 2019): 562–68. https://doi.org/10.1177/1747954119837688.

Debbie (Deb) started powerlifting and Olympic lifting in High School as part of her track team's programming; She continues to train in order to remain athletic. Inspire US allows Deb to share information related to training, lifting, biomechanics, and more.
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