Lark has competed at a semi-professional level in XC skiing, road cycling, and mountain biking. His passion for fitness and teaching extends back to his early days cycling, skiing, playing tennis and running in the countryside of Western Massachusetts. His certification as a Strength and Conditioning Specialist allows him to train you like a professional athlete. Visit 
This little ribbed rubber tube works better than any other therapy I have seen for tennis elbow or tendonitus of the wrist. I don't often pitch products, and I have nothing to gain from pitching this one. In fact, I have given a few of these away to clients, so I'm actually in the hole. But I believe in this product so much that I have to share.
Standard therapies for tennis elbow include icing the elbow, taking over-the-counter anti-inflammatory medication, and altering or ceasing whichever activity is giving you this repetitive stress injury. (If you're a tennis player, perhaps you need to aim the ball less and hit through with more hips, for instance.)
As a strength coach, I like the Thera-Band FlexBar as a daily, light exercise you can perform while at your desk to strengthen the forearm and wrist so it has a higher tolerance before it begins to hurt. If you happen to type for a living, I highly suggest the FlexBar. It is also great for gentle stretching and range-of-motion wrist exercises, as well as a deep conditioning arm massage. Just five minutes a day, incorporating all of the above, will make a world of difference. And ideally, this all happens before the onset of any pain.
If you're already experiencing elbow or wrist pain, consult your doctor or physical therapist and proceed cautiously. Incidentally, these bars also make very nice self-foot massagers.
Yellow — easiest resistance
Red — slightly more resistance
Green — even more
Blue — the thickest, provides the most resistance