"Muscle strength and flexibility characteristics of people displaying excessive medial knee displacement"- Bell et al ', Archives of Physical Medicine and Rehabilitation '07.
Pretty cool. The authors took subjects who's knees exhibited medial knee displacement during a squat. They then gave them heel lifts to see if it corrected. If it did, they studied their lower extremity strength and compared it to those who did not display medial knee displacement. They had GREATER hip extension and external rotation strength than those with normal squat kinematics! They went on to make recommendations for ankle strength/ROM.
So much for "training the glutes and hamstrings to fire better". Just teach them to squat and land better period- don't try to 2nd guess the body as to what muscle is firing how much and when. And it always amazes me how quickly adolescents adapt with a minimal amount of intervention. Just take the time.