Shin Splints
Definition: Inflammation of the tendons on the inside of the front of the lower leg. (Sports-medicine specialists don't like to use the term "shins plints" because it commonly refers to several lower-leg injuries.
Symptoms: An aching, throbbing or tenderness along the inside of the shin (though it can radiate to the outside also) about halfway down, or all along the shin from the ankle to the knee. Pain when you press on the inflamed area. Pain is most severe at the start of a run, but can go away during a run once the muscles are loosened up (unlike a stress fracture of the shinbone, which hurts all the time). With tendinitis, pain resumes after the run.
Causes: Tired or inflexible calf muscles put too much stress on tendons, which become strained and torn. Overpronation aggravates this problem, as does running on hard surfaces, such as concrete sidewalks.
Beginning runners are the most susceptible to shinsplints for a variety of reasons, but the most common is that they're using leg muscles that haven't been stressed in the same way before. Another common cause of shin splints among beginners is poor choice of running shoes, or running in something other than running shoes. Runners who have started running after a long layoff are also susceptible to shins plints because they often increase their mileage too quickly.