One thing that will help prevent getting tendonitis is a proper diet. And one of the basic components of good, anti-inflammation promoting nutrition is getting enough vegetables with every meal. Vegetables do a lot to push your body toward the alkaline side of the pH-scale, and can counteract (to a certain degree) the effects of eating too much acidic (and potentially inflammation-producing) red meat.
Of course, it’s helpful to know what is and isn’t a vegetable. Recently, the US Congress showed just how difficult making this determination can be by deciding that pizza is now legally to be considered a vegetable.
Apart from the blatant political self-serving–and the complete disconnect from reality that politicians apparently experience–no one should be fooled into believing that pizza will actually serve to replace a vegetable. But if you suffer from tendon inflammation, adding more (real) vegetables into your diet is a good step to take. Another would be adding a good supplement or two, which you can read about here.