An abductory twist is a common finding during a gait analysis and can be due to a number of different things and is commonly associated with ‘overpronation‘. It is a sudden abduction of whip of the heel medially or in the direction of abduction just as the heel comes of the ground. This video shows what it looks like:
More videos here.
The causes is a foot that is pronating as the heel comes of the ground or a muscle weakness around the hips.
My advice if you have an abductory twist:
1. Get a gait analysis done by a clinician who is familiar with running
2. Find out the cause of the twit
3. Treat it.