Stand on a six-inch platform or step so that the forward, lunging foot will undergo an exaggerated downward acceleration. Start with erect posture and feet directly under the shoulders; step down and forward with one foot. After the forward foot makes contact with the ground, move into a squat position so that the thigh of the forward leg becomes almost parallel with the ground. The upper body may incline forward slightly as this happens. Emphasize action of the gluteal muscles and hamstrings to reverse the squat and return the forward leg onto the platform, under the trunk. Complete one rep by returning to the start position.
3. Low-Back Extension with a Twist
Lie on the stomach with arms by the sides, hands extended toward feet, and palms touching the floor. Contract the back muscles to lift and twist the upper body to one side during the first rep. Return to the starting position and then lift and twist the torso to the other side during the second rep. Continue alternating sides for the desired number of repetitions. Be sure to fully untwist the upper body each time the trunk moves back toward the ground so that the stomach and chest, not the sides, touch the ground. Perform these movements rhythmically and smoothly while maintaining good control.