The Back Extension on the ball is a great exercise for improving lower back strength.
		How it's done: Use a wall to anchor your feet Start with the ball placed so that the apex of the ball is near the upper thigh Place your arms across your chest Drop down over the ball until you approach the floor Maintain natural lumbar curvature Then raise up keeping head in line with the shoulder, torso, and hip Start out with 8-12 slow controlled reps
photos and animation by Karen Day