Medicine balls are tools that can be used in various range-of-motion, rehabilitation and strength-building exercises. The balls can be used safely by men, women and children. The size of medicine balls preferred by most women range from 4 to 10 inches, depending on your body type, training goals and strength level. Choosing the appropriately-sized ball will provide a comfortable, safe and effective workout.

Sport Training

Select the exercises first, then the size and weight of the medicine ball. If you are using a medicine ball to strengthen your softball pitch, use a ball with a smaller diameter. A soft, 4-inch ball will fit into the palm of your hand and allow you to develop arm strength for throwing a softball. If you are using a medicine ball to strengthen your overhead throw for basketball, use a larger medicine ball to match the diameter of your basketball. If you're a volleyball player, select a volleyball-sized medicine ball for your exercise routines.

Body Type and Ball Size

The size of your medicine ball also depends on the size of your body. If you have small hands and a small frame, use a medicine ball that is 4 to 6 inches in diameter. The smaller-diameter balls usually are also lighter. If you have medium to larger hands and a larger body structure, you may be able to use medicine balls that are larger in size -- such as 10 inches -- and heavier. In addition, as a woman, your upper body strength is generally less than a man's, so you should start with a lighter ball when performing upper body exercises and gradually work your way up to the heavier balls.

Speed Training

If you are using a medicine ball to train for speed, The American College of Sports Medicine suggests selecting a smaller-diameter ball. These lighter-weight and smaller-sized balls will allow your joints to safely move through the quick motions required for speed training. If you are using a medicine ball for strength and speed, where your movements will be slightly slower, choose a medium- or larger-sized ball. Begin with a lighter ball and build up to the heavier ball; if you lose control of the ball, it's too heavy.

Training Routines

Your training routine may require more than one medicine ball. For upper-body exercises, use a lighter-weight, smaller-sized medicine ball. For your lower-body training, you may be able to hold a larger-sized ball. If you will be performing single-arm exercises, a smaller ball will be easier to hold. Jump USA suggests a 6-pound medicine ball, which is approximately 8 inches in diameter, for a woman's workout.