A Biomechanical Comparison of Back and Front Squats

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A Biomechanical Comparison of Back and Front Squats in Healthy

Trained Individuals.Gullett JC, Tillman MD, Gutierrez GM, Chow JW.

J Strength Cond Res. 2008 Nov 8. [Epub ahead of print] Links

The strength and stability of the knee plays an integral role in

athletics and activities of daily living. A better understanding of

knee joint biomechanics while performing variations of the squat

would be useful in rehabilitation and exercise prescription. We

quantified and compared tibiofemoral joint kinetics as well as muscle

activity while executing front and back squats. Because of the

inherent change in the position of the center of mass of the bar

between the front and back squat lifts, we hypothesized that the back

squat would result in increased loads on the knee joint and that the

front squat would result in increased knee extensor and decreased

back extensor muscle activity. A crossover study design was used. To

assess the net force and torque placed on the knee and muscle

activation levels, a combination of video and force data, as well as

surface electromyographic data, were collected from 15 healthy

trained individuals.

The back squat resulted in significantly higher compressive forces

and knee extensor moments than the front squat. Shear forces at the

knee were small in magnitude, posteriorly directed, and did not vary

between the squat variations. Although bar position did not influence

muscle activity, muscle activation during the ascending phase was

significantly greater than during the descending phase.

The front squat was as effective as the back squat in terms of

overall muscle recruitment, with significantly less compressive

forces and extensor moments. The results suggest that front squats

may be advantageous compared with back squats for individuals with

knee problems such as meniscus tears, and for long-term joint health.

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Carruthers

Wakefield, UK