At the Movement Assessment Technologies we use squats daily in the rehabilitation and development of movement competency in our patients and clients. We often modify squats in the position of the feet or upper body to create different stresses and loads through the system depending on what an individuals goal is.
One under utilized modification to the squat is "depth" and knowing what reactions occur through the knee. This little info-graphic may give you an idea on where load can be focused depending on depth. Consider this next time you are rehabilitating a patient or want to develop greater muscular capacity.
Shapour, J. (2015). The Effect of Altering Knee Position and Squat Depth on VMO : VL EMG Ratio During Squat Exercises Journal: Physiotherapy Research International.
Nagura, T. (2002). Mechanical loads at the knee joint during deep flexion. Journal of Orthopaedic Research, 20(4), 881-886.
Caterisano, A. (2002). The effect of back squat depth on the EMG activity of 4 superficial hip and thigh muscles. The Journal of Strength & Conditioning Research, 16(3), 428-432