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Biomechanical Analysis of the Back Squat

Purpose

The purpose of the back squat is to increase strength in the hip and knee joints. The muscle groups involved are the plantar flexors (soleous and gastroc), knee extensors (quadriceps), hip extensors (glutes and hamstrings), and the trunk extensors (erector spinae).

Variations

There are two main variations of the barbell back squat, Olympic (high bar placement) and powerlifting (low bar placement). The Olympic, or high bar, squat requires a narrow stance, bar placed on top of the trapezius muscles, and forces a forward shin angle, emphasizing the quadriceps. The powerlifting, or low bar, squat has a wide stance, the bar resting across the back over the rhomboids and rear deltoids, which emphasizes the hips and low back. Below are pictures showing joint angles and bar placement:

Olympic (High Bar)

Powerlifting (Low Bar)

Below are a summary of the differences in the two types of back squat:

High Bar

• Greater knee flexion increases work done by knee extensors (quadriceps)
• Decreases trunk extensors (erector spinae) and hip extensors (hamstring) work

Low Bar

• Greater hip flexion increases work done by trunk extensors (erector spinae) and hip extensors (hamstrings)

Technique

For Both

• Tight core
• Tight upper back
• Unlock the hips before knees
• Chest erect

For Low Bar

• Sit back so that hips are at 45 degree angle at "bottom" postion (thigh parallel to ground)
• Shins are perpendicular to the ground

For High Bar

• Sit straight down over heels
• Shins slightly forward with knees no further forward than toes
• Hips are lower than knees in the "bottom" position

Common Mistakes

• Knees fold in (valgus stress)
• Upper back separates (poor upper back strength and trunk extensor strength)
• Not squatting to, or below parallel, shows signs of poor glute and hamstring strength

Application

High Bar Squat

• Good for quad and core development
• Applicable for sprinters (drive phase)

Low Bar Squat

• Good for eccentric loading of the hamstrings and low back development
• Important for football and other contact sports
• Many sports start in similar to "bottom" position of low bar squat