Split Squats

Stand as if for a lunge: step one foot back about 2-3 feet. Squat down. When the back knee just brushes the floor, the front knee should be vertical over the foot. If the front knee is ahead of that foot, spread the feet further.

Keeping the feet in position, the head up, the chest lifted, and the abdominal muscles tight, slowly lower yourself until the back knee brushes the floor, then slowly stand up. Let the effort come from the glutes and hamstrings of the front leg.