Start in a standing position with the feet together. Standing on the left leg, lift the right leg off the floor and bring the knee up toward the chest.
Lean your upper body forward and reach your right leg out behind you.
Bring the knee back up toward the chest and repeat. Perform for 30 seconds on one leg, then switch legs.
Add variety by moving the arms in a running motion or bringing the arms close to the floor, deepening the lunge.