In Tennis Elbow, we discussed how the elbow is damaged and surveyed how that damage can be prevented and treated, and in Choosing Racquets and Strings to Prevent Tennis Elbow, we looked at the equipment factors players usually think of first. Here, we'll consider the smaller pieces--grips, overgrips, and balls--that may make a big difference in helping you avoid tennis elbow.
Grip size: While a grip that's too large or small will tend to force you to grab the handle too tightly and thereby increase strain on your forearm, a grip that's too small is likely to be worse, because it's more likely to try to turn in your hand. A grip that's less than 1/8" too small is easily remedied, though, because it can be fattened adequately by adding an overwrap, whereas an overly large grip would have to be shaved down at a pro shop. Adding multiple overwraps to make up for more than a 1/8" deficit isn't advisable, because it rounds off the bevel edges too much. See Finding Your Tennis Racquet Grip Size.
Overgrip to prevent slipping: Even with the right grip size, you're likely to end up gripping your racquet too tightly if the handle becomes slippery. A good overgrip can keep your grip dry and prevent slipping, which is safer both for your arm and for your racquet, as racquets are frequently broken by slipping out of the player's hand and slamming into the court or fence. See Photo Illustrated: How to Apply an Overgrip.
Standard balls: A lighter tennis ball would be better for your arm, but all new, standard tennis balls have essentially the same weight, 56.0-59.4 grams. A ball that has lost most of its fuzz will feel noticeably lighter to many players, but it will also change the game by, for example, responding less to spin. The opposite effect occurs when the fuzz on newer balls fluffs up excessively and becomes heavier by holding more moisture and particles of dirt or clay. Longer fuzz will also change the game by increasing the ball's response to spin and decreasing its speed. The best way to avoid overfluffed fuzz is to avoid hard-court balls on clay and on some very slow hard courts.
Alternative balls: If your arm can't take the shock of a standard tennis ball, you might want to try playing with a Soft Tennis ball, which weighs only 30-31 grams, or an ITF Stage 2 ball, which weighs only 47.0-51.5 grams. Soft Tennis is very popular in Asia, where, in addition to greater arm safety, players enjoy the longer rallies that result from a slower ball. The ITF Stage 2 ball is meant for introductory training, especially of juniors, but advanced players often find it fun too.
Babette Pluim, M.D., Ph.D. and Marc Safran, M.D. From Breakpoint to Advantage: A Practical Guide to Optimal Tennis Health and Performance. Racquet Tech Publishing, 2004.
Howard Brody, Rod Cross, and Lindsey Crawford. The Physics and Technology of Tennis. Racquet Tech Publishing, 2002.