Photo: Martha Edwards

If you're spending the warm summer months on the courts playing tennis, good for you -- not only is tennis fun, it's a great way to get fit too. But if you're not used to swinging your racket, or you've been hitting every day, a case of tennis elbow can leave you relegated ball boy.

Caused by overuse of the tendons in the arm, it's more than just a painful nuisance -- it can seriously hamper your summer fun. And it's not just caused by tennis -- painting, gardening or any repetitive arm movement can lead to the condition. Luckily, a recent study found that for those afflicted with tennis elbow, an $8 rubber bar may help get them back on the courts.

The FlexBar is a rubber handheld therapy device that you use basically by bending and twisting. Sounds too simple to be effective, right? Don't be fooled -- it really does work.

Findings from the Nicholas Institute of Sports Medicine and Athletic Trauma found that using the Flexbar improved pain, tenderness and strength in tennis elbow sufferers by 76 percent, compared to 12 percent who underwent traditional therapy only. In fact, the improvement in FlexBar patients was so drastic that they actually stopped the study early so they didn't have to prolong the suffering of participants in the control group.

Of course, don't try this at home -- consult a professional if you have tennis elbow, but if you're itching to pick up your racket again, consider giving the FlexBar a try.