1) Train low impact, race high impact.
If you are planning to run for miles or go up and down rugged trails then you need to spend some time preparing for that course, but you can still train your body without placing a lot of impact on your joints and tendons. You can be prepared for the endurance challenge on race day without needless extra strain on the cartilage and connective tissue. Including swimming rowing cycling or elliptical machines and your work out can be very intense yet still protect your joints from high impact. Vary your training routine in order to not put yourself at risk for overuse injury before the race even begins.
2) Keep your muscles pliable.
Everyone has had a cramp or muscle spasm before, but when you train routinely without appropriate recovery between workouts your muscles can develop into a chronic strain pattern and can be so locked-up that they cannot relax and it can even affect the circulation to the muscles. This is especially symptomatic around the central nervous system, particularly the neck and back. Appropriate warm-ups are nice for 3 to 5 minutes prior to a workout, but nothing is more important than a recovery routine that involves taking the muscles back out to length and getting your joints back to full range of motion without restriction. This is best done on a daily or every other day basis and usually separated from your work out. The muscles are typically very flexible right after the work out but that night or the next morning the lactic acid has built up resulting in stiffness and soreness. Take that as a signal your body is recovering and growing muscle but it’s also reminding you to stretch!