Abductory twist. The abductory twist is the rapid media movement of the heel at the time of heel off if there are increased pronation moments occurring during the time of late mid stance this will prevent the subtalar joint from supinating as rapidly as it needs to and therefore also prevent the tibia from externally rotating as fast as it should. When combined with the pelvis which is externally rotating about the latest stance foot will create an increase in elastic strain energy within the transverse plane which will then be resolved into this abductory twist motion of the heel whipping medially at the time of heel off due to the frictional friction from the heel being suddenly released at the time of heel off here we see the abductory twist occurring in the left foot at the time there and this is caused by this combination of late midsstance pronation moments in combination with the transverse plane movements of the pelvis about the foot.
Abductory twists may also be evidenced to by concerned wear patterns in the forefoot and leather sole shoes which occurs do the rotational motions of the foot relative to the ground. This is Dr. Kevin Kirby on abductory twist.