Start from standing and step your left leg behind you and to the right so your thighs cross, bending both knees to 90 degrees as if you were curtsying. Make sure your front knee is aligned with your front ankle.
Return to standing, and switch sides to complete one rep.
Do eight reps (a curtsy lunge to the left and right equals one rep) or count 16 total reps (a curtsy lunge to one side equals one rep).