Air Squats

This fast-paced squat will set your bottom half on fire in a jiffy.
Air Squats
  1. Stand with your feet shoulder-width apart.
  2. Perform a squat, lowering your body until your thighs are parallel to the floor. Be sure to keep your back straight and knees behind your toes.
  3. Immediately push up from your heels, straighten your legs and squeeze your glutes.
  4. 4. Quickly lower into a squat again, and repeat.