Take a fighting stance with your fists up in guard. Lift one knee up toward your chest - the chamber - then snap your lower leg out, kicking forward with the ball of your foot, toes pulled back. Re-chamber the knee just as fast, set the foot down, and kick with the other leg. The chamber is what makes it a kick: knee up first, snap out, snap back - never a straight-leg swing from the floor.

Works: quads, hip flexors, glutes, core

Breathing: Sharp exhale on the snap of every kick, inhale as the foot returns.

Common Mistakes: Swinging the whole leg up straight instead of chambering, leaning back heavily to get the kick higher, and dropping the guard as the leg goes out.

Make Easier: Kick low - shin or knee height is fine - keep the pace easy, and rest your fingertips on a wall or chair if balance is shaky.

Make Harder: Kick higher and faster without sacrificing the chamber, or move on to Side Kicks or Turning Kicks.