Tips for choosing medicine balls

Versatility, portability, power—these are just a few of the things that make medicine balls a popular part of so many people's strength-training routines. Start toning and building your core with the right balls using these features to guide you.

Weight: Enhance performance and athletic ability using these general guidelines:

• Go lighter for speed training and improving reflexes
• Choose heavier balls for strength training and improving core stability
• Start with a ball that's 30-50 percent of your one-repetition maximum. For example, if you curl a 30-pound barbell, look for a ball in the 9- to 15-pound range.

Size: Match the size of the ball to your functional training exercises for maximum success.

• Large: Best for multi-joint moves like overhead throws
• Medium: Best for overall weight training
• Small: Best for working your core