It's also the most talked about, with cures and remedies ranging from copper bracelets to cortisone shots, with acupuncture and tiger balm somewhere in between.

What can you do to prevent tennis elbow? Plenty. Knowledge is power, and if you take the next few minutes to learn why this repetitive stress injury happens and how to avoid it, you'll develop into a stronger, safer, more effective player. Class is now in session:

DON'T OVERDO IT. Technically, tennis elbow is an inflammation of the tendon (tendonitis) where it attaches to the muscles in the forearm that extend your fingers and wrist. The repetitive stress of hitting too many tennis balls, too hard, with weak arm muscles, poor form or ill-fitting equipment causes degenerative changes (little tears) in the tendon. That in turn produces local swelling and pain and — ouch! — next thing you know you're reaching for the Aleve. The good news is, like all overuse injuries, you can prevent tennis elbow if you understand the basics of self-care.

TRAIN FOR NET GAIN. The smartest way to prevent tennis elbow is to train and get fit before you play. Tennis alone will not make you strong or flexible or give you endurance. There's too much starting and stopping and too little steady exertion, especially when every third shot flies over the fence. Get smart. Condition yourself off court with a variety of aerobic activities — biking, running, whatever mix you like — at least three to five times a week, at least 30 minutes per session.

Strength training — targeted exercises, using free weights or machines — is crucial. Have you seen Rafael Nadal in action? Believe me, he didn't get that gorgeous body practicing his drop shot.

And don't forget to balance your strength training with mindful stretching. Always warm up before you play, because fluid, flexible muscles can withstand the repetitive stress of high-speed tennis much better than muscles that are tight and tense.

TAKE SOME LESSONS. Write this on the blackboard 100 times: Poor playing technique is a major cause of tennis elbow. Punching at the ball, a lame serve, a weak backhand and lack of follow-through all increase the stress on your muscles and tendons. The better your form, the lower your risk, the higher your score.

CHECK YOUR RACQUET. Get a pro to make sure your racquet fits you properly — not too big, not too heavy. Focus on your grip size. Too small a grip leads to muscle fatigue. So can holding the racquet too tightly. Too large a grip makes for a weaker stroke. Avoid high string tension and low racket flexibility, which transmits too much force directly to your forearm muscles.

STRETCH AND STRENGTHEN. Strong, flexible forearms are a huge help in preventing tennis elbow. Clicking the keyboard just won't do it. Start with these and learn more:

— SQUEEZE: Grip down on a tennis ball with your arm extended out in front of you, wrist straight, thumb on top. Squeeze as hard as you can, contracting your fingers and forearm muscles, and hold 5-10 seconds. Breathe. Release and repeat 10 or more times. Do it every day, no excuses, watching TV or waiting for the bus.

— CURL. Hold on to a 2-5 pound weight. If that's too heavy to start, switch to a can of peas and add weight gradually. Now relax your forearm on a table with your hand (holding the weight) hanging over the edge, palm down. Slowly flex your wrist 10 to 20 times. Then turn your hand over so the palm faces up, and flex some more. Switch arms, and repeat.

— STRETCH. To increase flexibility in your forearm extensors, extend your arm in front of you, palms down. Use your other hand to push the extended hand up into a vertical position, fingers pointing to the sky. Hold for 10 to 20 seconds; repeat 10 times. Then push the hand down so that the fingers point toward the floor. Hold for 10-20 seconds; repeat 10 times. Switch arms, and begin again.

ENERGY EXPRESS-O! COMMIT TO SELF-CARE

"The difference between involvement and commitment is like ham and eggs. The chicken is involved; the pig is committed." — Martina Navratilova

Marilynn Preston — fitness expert, personal trainer and speaker on healthy lifestyle issues — is the creator of Energy Express, the longest-running syndicated fitness column in the country. She has a website, http://marilynnpreston.com and welcomes reader questions, which can be sent to MyEnergyExpress@aol.com.