Stand with your feet shoulder width apart. Start the movement by bending your knees and sitting back with your hips. Go down as far as you can and quickly reverse the motion back to the starting position. Keep your head up and back straight throughout the move.
Lie face down with your arms extended out in front of you. Raise your arms, legs and chest a few inches off the floor and pause at the top of the rep. Squeeze your lower back and then lower to the starting position.
Grab the handles of the pull-up station with your palms facing away from you and your arms fully extended. Your hands should be around shoulder-width apart. Squeeze your shoulder blades together, exhale and drive your elbows towards your hips to bring your chin above the bar. Lower under control back to the start position.
Lie down on the floor with your knees bent and, if possible, hook your feet under something that will prevent them from moving. Place your hands behind your head and tense your core as you lift your torso up so your upper body forms a V shape with your thighs. Lower under control back to the start position.
Set up with your weight supported on your toes and hands beneath your shoulders, body straight. Take care to keep your core locked so a straight line forms between your head, glutes and heels. Lower your body until your chest is an inch from the ground then explosively drive up by fully extending your arms.