With spring track season now underway for over 3 weeks, in New Jersey, we thought it would be good to explain the difference between shin splints vs. stress fractures of the lower leg.A shin splint is an inflammation of the tissue running along the bone in the shin. Shin splints develop when the muscles and tissues tear due to the repeated pounding of running. This is usually caused by inflexible calf muscles in the back of the lower-leg, improper shoe choice, shoes that are not providing enough cushion, or ramping distance too quickly. A stress fracture is a very small crack or group of cracks that forms in the bone itself, similar to the white crease that would develop if you bent a credit card a few times.The major difference in differentiating between a shin splint and a stress fracture is usually what we call “point tenderness”. With a shin splint, if you run your fingers along the shin, it will usually hurt all along the bone as you pass your fingers down the leg. With a stress fracture, there is usually one specific spot (or multiple spots) that hurts really badly. These spots are usually about the size of dime. The rest of the area will be much less tender. In addition, people with stress fractures will also have pain with walking, sitting and even sometimes complain of pain that wakes them up from sleeping at night.Stress fractures are much less common than shin splints. In most cases, a shin splint is a more likely explanation for shin pain, especially in new runners.A bit of bad news in diagnosing stress fractures, because they are very small cracks they may not show up on an x-ray. A bone scan or MRI are often the only way to actually see them. This often leaves a definitive diagnoses up to the doctor’s judgment, rather than hard and fast pictures. If you have a stress fracture, you will need to stop running until it heals. Referring back to the credit card with the crease analogy, if you keep running on a stress fracture the stress fracture can become a complete fracture just as if you keep bending the credit card it will go from a white crease to completely snapping in half. So when that stress fracture appears, you either stop running on it and let it heal or if you keep on running then the bone itself is going to break and you’ll have a real fracture to deal with — which is a far more serious problem.If you do have a stress fracture, then the best method to keep training is aqua jogging or aqua running. This means running in a swimming pool, usually wearing a flotation belt. It isn’t a lot of fun or very interesting (imagine swimming laps by in the jogging position and going much more slowly than a swimmer). But it is very effective at keeping up your cardio and maintaining running muscles in the legs, with zero impact on the lower-leg. Swimming is also a great way to keep up fitness, because again it is non-impact on the lower-legs.If you find yourself in this situation, first see a physician. If you are diagnosed with a stress fracture, then you’ll need to come up with a non-running training plan while you are recovering. If it is shin splints, then you’ll likely need some rest or practice modification (limited running, biking, etc), stretching, possibly new shoes and if prescribed by your physician the use of various therapeutic modalities (ice, ultrasound, electrical stimulation).