Take a fighting stance with one foot back and your fists up in guard. Drive your rear knee up and forward hard, as though striking a target at waist height, rising onto the ball of your standing foot and pulling your hands down toward the knee as it comes up - then set the foot back down and strike again. Finish the set and switch legs. Hips drive the knee, hands pull down to meet it, and the guard snaps back up between reps.

Works: hip flexors, quads, glutes, core

Breathing: Sharp exhale with every knee strike, inhale as the foot returns.

Common Mistakes: Lifting the knee slowly instead of striking with it, leaning far back to get the knee higher, and leaving the hands up doing nothing instead of pulling down into the strike.

Make Easier: Slow the pace, drive the knee to hip height only, and rest a hand on a wall if balance wobbles.

Make Harder: Pick up the pace and drive the knee chest-high with every strike, or combine with Front Kicks or Elbow Strikes.