With spring around the corner, runners of all abilities are gearing up to race in their local 5Ks, 10-milers, half-marathons, and marathons. But as training volume increases, so do injuries.

During the months of March, April, and May, stress fractures of the feet are very common. With the Boston Marathon in April and the Broad Street Run in May, runners seek help to avoid deferring their race bibs.

About four to eight weeks before an endurance race such as the Broad Street Run, runners ramp up their mileage. The long runs get longer and the total quantity of weekly miles rises. This repetitive stress on the feet can wear on the bones and lead to small cracks called stress fractures, which cause pain and swelling. If ignored, the stress fracture can progress into a more complicated break, requiring a longer recovery time and force the injured athlete to withdraw from a race.

In addition to running volume, other training-related causes of stress fractures include shoes that do not fit properly, changing the style of the shoe (i.e. minimalist vs neutral), changing the heel-to-toe drop, changing training terrain, and muscle imbalances that alter one’s running gait. In this article we focus on run volume.

What is a stress fracture? A stress fracture is different than the type of fracture most people think about. Take a piece of wood and snap it in half. This is a fracture. But if you take a piece of metal, such as a wire coat hanger, and bend it repetitively, small microscopic cracks will begin to develop. This is similar to a stress fracture.

In a stress fracture, the break (fracture) does not go entirely through the bone. So, how does this happen? Every time someone exercises, the bones are stressed and start to break down. However, during rest or lower volume days, the bone builds back up. Occasionally, when someone starts training for a race, running volume increases faster than the bone is able to repair and rebuild itself. The bone becomes inflamed and, like the wire coat hanger, eventually cracks. Stress fractures are seen in patients of all athletic abilities.

Diagnosis and treatment. Most stress fractures of the feet can be seen on an X-ray. They are often treated by wearing a boot for roughly four to eight weeks. (The duration is dependent on the severity of the stress fracture.) If a stress fracture is untreated, it may break the whole way through the bone and require surgery.

How to prevent. As a rule of thumb, the volume of running should increase no more than 10 percent a week. That volume can be measured in quantity of time spent running or the number of weekly miles. There are lots of different training plans and training methods to get to the finish line. But the key point in the various plans is starting to train well in advance of race day and allowing time for the body to properly prepare itself for such an event. The longer the distance of the race, the longer the training time should be leading up to it.

What to do if you have symptoms: If you start experiencing pain and/or swelling of a foot while running or after a run, take a few days of rest. If rest does not make the symptoms go away completely, have it evaluated by a medical professional. You may have a stress fracture of the foot. Don’t risk missing your race. Get foot pain checked out early before it becomes a bigger problem with a longer healing time.

Kristen Frank, PA-C, is the lead physician assistant for Rothman Institute Urgent Care in Marlton and in Limerick.