One of the best ways is to consistently stretch your two calf muscles. When you strain or develop Achilles Tendonitis you have simply gone beyond its tissue tollerance. Often it's due to shorten muscle/tendon collagen complex and the Achilles Tendon (AT) simply can't keep up with the forces placed on it. For example...when you start a 1/2 marathon training program for the first time stretching your calf requires 2 stretches b/c there are 2 separate muscle that blend into the AT. First, stretch your calf w/ your leg completely straight. This will be addressing your gastroc muscle. Second, don't move your feet, simply bend that straight knee. This puts the gastroc muslces on slack (b/c it crosses the knee joint). Now you are stretching your Soleus muscle. Duratioin: 30 seconds for both the gastroc and soleus stretch, both legs. If you know you are tight, you should be stretching every time you exercises. Don't skip the bent knee or Soleus stretch either! It can be involved in so called 'shin splints' or clinically Medial Tibial Stress Syndrome. So, there are actually 2 reasons to stretch the Soleus muscle. Make sure not to over stretch, and don't create 'symptoms' in your AT. You want to only feel the stretch in your calf muscles. Stretching isn't the most exciting thing to do in the world, but it will may help keep you injury free....so you can continue having fun running or riding with your friends.