Are Squats a Hip-Dominant or Knee-Dominant Exercise?

Technique

You can do squats with loaded barbells, an unweighted bar, dumbbells, kettlebells, resistance bands, a Smith machine or other weight machines -- or just with your own body weight, which is probably the best way to start. You want to flex your knees fully so you can drop your backside as low to the floor as possible. The quads, glutes and hamstrings, with help from the plantar flexors in the ankle, do much of the work to drop you down and help you rise back up.

Hips, Knees -- and Ankles

Although it may seem that the knees are doing mountains of work along the way, generally the hips -- extended by the glutes and related muscles -- are actually dominant during the squat, creating the needed twisting forces, or torque. “Yes, hip/trunk extensor torques tend to be larger than knee extensors or plantar flexors in a standard squat,” notes Duane V. Knudson, a biomechanics professor at Texas State University. “This will usually be the case unless you have a machine or do unusual (front) squats with minimal trunk lean.” For regular squat exercises, the glutes experience greater turning force -- “net moments” in biomechanics-speak -- and are typically stronger than the quads, which extend the knee, Knudson notes.

Variables

Different types of squats demand different contributions of the major players of the lower body: the glutes, quads and ankle flexors. The powerlifting squat, with the barbell low behind the shoulders, demands greater force from the hip joint, which is stronger than the knee joint, notes kinesthesiologist James Griffing of the exercise website ExRx.net. The front squat -- barbell held atop the collarbone instead of the shoulders -- asks more of the knees, as does the sissy squat and lever barbell squat. The bodybuilding squat, with the barbell high on the shoulders, distributes torque evenly between knee and hip.

Benefits

Squats can be “one of the safest and most functional exercises you’ll ever perform,” notes Incledon in her book “Strength Training for Women.” Get a friend or workout buddy to give you feedback on your form, particularly making sure you don’t elevate too quickly and damage your knees. Because squats work so many large muscle groups and encourage joint flexibility, they encourage functional and sports-specific strength. If you’re an athletic Nestie, learn the split squat -- one leg forward, one back -- and the one-legged box squat as soon as you can. These have a good record in helping girls and women avoid anterior cruciate ligament injuries.