(A) Start with one foot in corner, head up, and back straight. Shoulders and elbows should be at 90 degrees with fingers pointing up.

(B) Move your hips, abdomen and chest into the corner all in line and at the same time until a stretch is felt. Do not stretch into pain.
If pain is felt, back off. It is important to do this exercise on both legs. So repeat with the other foot in the corner now.