The attic door swings open.

Behind the ancient bumper pool table, beside the old Zim-Zam set and underneath the ugly pair of K-Tel skis lies a round, leathery object covered by two decades of dust. At first, it looks like an old, warn soccer ball or volleyball.

But to many fitness trainers around the world, that simplistic medicine ball is the answer to all their workout prayers.

Once an invaluable training tool for track athletes, fitness fanatics, and prizefighters, the medicine ball has been revamped from dormancy and is once again regarded as a workout favorite for many trainers.

The value of the medicine ball is that it targets your core strength or the area that includes your back and your abs. Strengthening your core will directly fortify the joints in your elbows, shoulders, and knees, thus providing more raw power for your arms and legs.

So to put that old training tool back to use, try these abdominal exercises with the use of the medicine ball:

LEG RAISES: Get flat on your back and place your arms by your sides. Holding the medicine ball between your lower legs, slowly raise the ball until your legs are arched upward at an angle of 45 degrees (or approximately two feet off the floor). Slowly bring your legs (and the ball) back toward the floor as you squeeze your abs, stopping just an inch or two before hitting the floor. Repeat the motion for as many repetitions as you can.

SIT-UPS: Bend your knees slightly, keeping your feet flat on the floor as you lie on your back. Holding the medicine ball directly out in front of you, slowly lift your shoulders off the floor, lifting your upper torso until its bent at a 45-degree angle. Slowly let your back drop down to the floor before repeating this motion as many times as you can.

For an upper-body exercise, try this exercise to strengthen the triceps and the chest with the use of the versatile medicine ball:

PUSH-UPS: Place your hands atop the medicine ball with the ball directly underneath your chest. Your hands, obviously, will be placed close together. Your legs should be straight back with your toes planted straight into the floor. Push your torso straight up from the ball until your arms are fully extended. Then slowly lower your upper body until it nearly touches the ball. Repeat this motion as many times as you can for a great chest and triceps workout.