STARTING POSITION:
Lie on the floor face down and place your hands slightly wider than shoulder width apart while holding your torso up at arms length. Support your weight on your toes and hands. Keep the shoulders far from the ears retracting your shoulder blades. Contract your pelvic floor and core while keep your body straight. Raise your right foot towards the roof. Your knee should be extended.
MOVEMENT:
Start lowering yourself by bending your elbows until your chest almost touches the floor while you inhale. Press your upper body back to the starting position strengthening you body while you exhale. Repeat the movement for the specified amount of repetitions and then switch sides and repeat with the other leg. Make sure your shoulder blades are always retracted.
TIPS: The exercise key is quality over quantity. The trick is to perform the exercise using proper form.