HOW: Stand in between two sturdy objects like boxes, benches, or chairs. Something that is sturdy and won’t flip as you put your weight down into them. Place a hand on each object and with your arms straight, push down into them lifting your legs up. Keep your legs out in the front. From here, slightly bring one leg up and one leg down at the same time. Alternate doing that on both sides for the prescribed amount of reps.
FEEL: You should feel your core muscles working and your shoulder muscles working while holding your body up.
COMPENSATION: Keep your elbows locked out and at your side, don’t have them in front or behind your body. Don’t bend your knee or let your leg drop.