Gabe Mirkin, M.D.
Fitness refers to your heart. To become fit, try to work up to exercising for thirty minutes three times a week. All you need to jump rope is a ten foot rope. The ends of the rope should barely reach your armpits when you stand on the middle of it. You jump from and land on your toes, so you don't need special shoes.
Be careful when you first start. You have to spin the rope about 80 times a minute to keep it from tangling, and jumping that fast requires that you be in good shape. Start out by spinning the rope forward so you can see it as it passes. Bend your knees to absorb the shock of landing and protect the force of your feet striking the ground. To keep yourself from falling, bend slightly forward at the waist.