One sports medicine doctor explained to me why squats were considered to be bad for the knee. Since sports medicine doctors only see people with injuries, one can guess why they may have developed this belief. The individuals they treat certainly do not a constitute a random sample, let alone a representative population, as any scientist knows is essential to even attempt to formulate inferences. Torque Force Contrary to propaganda to the contrary, prominent weight training authorities demonstrate the squat with the knees flexing forward at the same distance as the hips flex backwards. Fredrick Hatfield, Ph.D., the first man to squat over 800 lbs, recommends the knees to extend over the feet with the back more upright for quadriceps development.
Torque force is necessary for the muscles and joint structures to adapt to the respected overload.
If the knee does not travel forward during the barbell squat, the quadriceps muscles are not significantly exercised. On the other hand, injury may result if the knee or lower back experience greater torque forces than what they are accustom. Try this simplified qualitative method in determining relative torque forces in the knee and hip joints. First take a photograph of the barbell squat in a full decent with a perspective perpendicular to the joints plane. Draw a line of force through the resistance on its center of gravity, straight up and down, parallel to the force of gravity.