Flare your trail foot to free the backswing turn
With one student, the instructor found the trail (right) foot pointing straight forward, which restricts the trail knee from moving and forces the club to travel up and steep instead of around the body. He opens/flares the trail foot so the knee can move, letting the body turn more around on the way back.
Channel: Danny Maude
Watch official source at 3:50Why this context matters
Aimed at senior/less-flexible golfers who feel they have lost distance.