The surprisingly versatile, compact bench offers numerous core-strengthening exercises.

The simple, effective challenge of a free weight workout remains one of the most efficient ways to build strength and muscle mass. The Universal decline bench, from parent company Nautilus, offers a wide variety of core workouts, from sit-ups to twists and more. Users can choose from two decline positions, while eight-inch padded foam rollers keep feet comfortably and safely in place. The bench measures 17 by 23 by 45 inches (W x H x D) and has a 200-pound maximum user weight.