Begin in a push-up position. Explosively alternate bringing each knee towards your chest and back.
Start in a seated position with heels on the floor and slightly leaning back. With your hands out in front of you, alternate arms tapping the floor on either side. Keep your core engaged and make sure your back is straight and not hunched.
Lie flat with your legs straight up in the air. Slowly reach up towards your toes.
Plank Toe Taps:
Start in a plank position. Lift your left foot, tap your toe out to the side and then return to center. Repeat with your right leg.
Sit down in the crab position. The body weight is on the hands. Brace your abs and alternate your legs kicking in the air. Don’t let your butt touch the ground.
Modify: Start with a lower speed and without jumping, slowly alternate lifting your legs in the air.
Source : www.myfitnessutopia.com