Upon reading several threads based on the squat I have seen this piece of advice several times "in order to perform a squat in good form you should concentrate on using your glutes and hamstrings (when referring to the concentric portion)." What is really meant by this? Simply to sit back and transfer the stress through the hips rather than the knees? The hamstrings don't play a part in the concentric phase because they are responsible for knee flexion. The concentric phase of the squat involves hip extension (glutes) and knee extension (quads). The hamstrings should only come into play on the eccentric portion of the squat. Someone please correct me if I'm wrong. This is only for my own knowledge, not that it makes a huge difference in actually performing the technique.