On the other hand, anatomic traits that lead to a more forward leaning squatting posture include: no heel elevation, restricted ankle dorsiflexion mobility, longer femur length, shorter torso length, narrower stance width, less abduction, a lower bar position on the back, greater gluteal strength and increased intent to target the hip extensors. (fitnessandpower.com)
The most common reasons for knee valgus include insufficient ankle dorsiflexion range of motion, poor hip mobility, poor gluteal strength and development and muscle poor coordination in the lower body in general. (fitnessandpower.com)
In one very influential study, Behm & Sale (1993) tasked subjects to perform ankle dorsiflexion training either isometrically or isokinetically (300 degrees / s), but where both programs required the subjects to «move as rapidly as possible regardless of the imposed resistance.» (strengthandconditioningresearch.com)