Feel the thigh fold to check your body separation
The lunge twist exercise trains separation through a feel. As you lunge and twist, you feel a fold in your thigh; the instructor says that same fold is what you feel in your golf posture when you separate your upper body from your lower body correctly during the swing. Feeling that fold in your thigh shows that your separation is getting better.
Channel: Golf with Aimee
Watch official source at 5:11