T Nation

Squatting Form, Re-think the Norm

Comparison of the angles and corresponding moments in the knee and hip during restricted and unrestricted squats.
Lorenzetti S, Gülay T, Stoop M, List R, Gerber H, Schellenberg F, Stüssi E.
Source
Institute for Biomechanics, ETH Zurich, Zurich, Switzerland. sl@ethz.ch
Abstract
The aim of this study was to compare the angles and corresponding moments in the knee and hip during squats. Twenty subjects performed restricted and unrestricted squats with barbell loads that were 0, ¼, and ½ their body weight. The experimental setup consisted of a motion capture system and 2 force plates. The moments were calculated using inverse dynamics. During the unrestricted squats, the maximum moments in the knee were significantly higher, and those in the hip were significantly lower than during restricted squats. At the lowest position, the maximum knee flexion angles were approximately 86° for the restricted and approximately 106° for the unrestricted techniques, whereas the maximum hip flexion angle was between 95° and 100°. The higher moments in the hip during restricted squats suggest a higher load of the lower back. Athletes who aim to strengthen their quadriceps should consider unrestricted squats because of the larger knee load and smaller back load.

Allowing the knees to translate anteriorly generally causes an increase in force at the knee, but decreased in the Hip and spine.
By keeping the tibia almost vertical, the force gets translated less into the knees and more into the hips and back.

For those of you with knee problems the second option may be more beneficial. For those with back and hip problems the first option may be better.