Crunches can also be done on an exercise ball and many feel it is more effective than standard crunches. You sit on the ball and place your feet on the floor about a foot apart. Roll back carefully on the ball and place your feet on the floor about a foot apart. Roll back carefully on the ball until you are lying with your back flat on the mat. Relax your abdominal muscles and then repeat. Remember to breathe during the exercise. Gravity resistance Some elliptical machines fold up to save space when not in use. They generally fall in the mid to higher price range compared to other types of home fitness equipment uses an adjustable metal frame and a gliding board or bench to perform exercises. The user lies on the board in various positions, and by pulling on a cable and pulley system, the weight of their body creates the resistance they will experience. Power rod equipment typically requires less space than a traditional home gym and is usually less expensive. The materials are not as durable,