Tennis elbow may be tennis's worst problem, afflicting roughly half of all recreational players at some point in their lives. In Tennis Elbow, we discussed the nature of the injury and surveyed how it can be prevented and treated. Here, we will look closely at choices in tennis equipment that can improve your likelihood of avoiding this painful condition.
On all but the gentlest tennis shots, the impact between racquet and ball produces shock and, unless you meet the ball exactly on your racquet's centerline, torsion (twisting force). How much these forces are transferred to your arm depends largely on the physical properties of the racquet, strings, and ball.
Racquet weight and balance: Racquet weight and balance make the biggest difference in how much potentially harmful force from the racquet-ball impact is transferred to your arm. Your arm likely is safest with a relatively heavy racquet (at least 10.5 ounces strung, preferably at least 11) that's not balanced overly head-light (within 5 points of even). More weight absorbs more shock, and more weight in the racquet head provides more resistance to torsion. Torsion is particularly stressful to your forearm muscles and the tendons that get damaged in tennis elbow. In addition to helping prevent tennis elbow, resistance to torsion enhances control, as your racquet is less prone to turning to an unintended angle as it launches the ball.
Racquet stiffness: A more flexible frame absorbs slightly more of the shock of the ball's impact, but it also vibrates with greater amplitude after impact. For many players, frame vibration is quite uncomfortable, but it hasn't been proven to cause tennis elbow or other injuries. Shock, however, is known to cause injury. Given only these considerations, a flexible frame would seem to be more certain to reduce the risk of injury, but a flexible frame also reduces control and power, and requiring the player to string tighter (for more control) or swing harder (for more power) would likely increase the risk of injury more than frame flexibility can decrease it. See How to Choose the Best Racquet for Control and Power for much more detail on how racquet specs influence arm safety, control, and power.
String tension, gauge, and resiliency: Looser, thinner, and/or more resilient strings are definitely easier on your arm, as they stretch more and thus spread the force of the ball's impact over a longer period of time, which reduces the peak shock. The main disadvantage of looser strings is less control. Thinner strings may slightly increase spin, but they and more resilient strings tend to break sooner. The most durable strings, made of Kevlar and similar materials, are also the stiffest, and they're much tougher on your arm.
For changes you can make in your grip size, overgrip, and type of ball to help prevent tennis elbow, see Choosing Grips, Overgrips, and Balls to Prevent Tennis Elbow.
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.