There is a certain amount of injury risk with any exercise program. Runners and sprinters have to be especially careful because of the intensity associated with the exercise activity or sport. Decrease your risk of injury by doing the following:
1) Don't over-train. Research shows that the lowest number of running injuries occur when you run three days a week. Each added day increases your chance of injury. Also, don't run too many miles in a week. Those who run 20 miles or less a week experience the lowest number of injuries.
2) You need rest between exercise days and walk breaks during long runs.
3) Proper warm-up. Dynamic stretching (using your muscles to warm-up your muscles) has been shown to prepare your body best for strenuous activity. A sample dynamic warm-up could be a 5-10 minute jog, prisoner squats, cone/ladder drills, lunges, etc. Static stretches would be done after your workout.
4) Speed training increases your chance of injury. Proper warm-up is critical. Speed training can be done 2 days a week (not consecutive days) as part of the athlete's overall training program.
If you feel sharp pain during any run or exercise, stop immediately and seek medical help if needed.