Stand with feet hip-width apart and hands on hips. Keeping shoulders relaxed and abs drawn in, take a big step forward with your right leg, bending both knees 90 degrees. Keep your right knee over your right ankle, left knee approaching, but not touching, the floor. Straighten both legs as you push back up, then bend knees again and repeat for reps. Bring right leg back to starting position and switch legs. Repeat for reps. When you're ready for more of a challenge, perform lunges while holding a 5- to 10-pound weight in each hand.