This video shows you how to do interval exercises to build muscle in your legs. Darin Steen, creator of the Fat Loss Lifestyle 12-Week Body Transformation Program, shows you how to do the king of all leg exercises... The Squat! Not just any squat, the smith machine back squat. It is the most effective and safe exercise for massive leg development that you will ever see! For safety purposes make sure you use a weight belt when doing this exercise. Keep your feet shoulder width apart, squat down, and explode up through your heels. Right after the squats you hit the treadmill nice and slow to boost recovery.