Shin splints are among the most frequent injuries to sideline runners-especially those who are just starting out or returning to the sport after a long layoff. But runners aren’t the only ones to feel the pain. Any activity that involves jumping (think: plyometricsHIIT workouts, CrossFit, etc.) can cause shin splints. Here’s what’s really happening and how to keep your legs feeling strong and healthy.

What They Are

Damage to the tibia and shinbone is a result of repetitive impact from running and moves likes sprints and jumps, according to John Gallucci Jr., D.P.T., president of JAG Physical Therapy. “This muscle breaks down and becomes inflamed. During the healing process, it forms scar tissue where one of the calf muscles adheres to the tibia, causing pain and tightness.” If you’re a victim of shin splints, you’ll feel a dull, achy pain on the inside or front of your shin that gets worse over the course of your training session and lingers after. In severe cases, you may feel a stabbing sensation.

Why it Happens

In short: weak feet. “The job of the posterior tibialis [the muscle immediately behind the shin] is to slow down the twist of the foot while running, walking, and cutting,” explains Jay Dicharry, a physical therapist and author of Anatomy for Runners. But when the muscles in the feet are weak, a higher load of force is placed on the muscles in the shin. You’re also more susceptible to shin splints if you have flat feet, adds Gallucci.

How to Prevent It

For runners: Add mileage slowly, don’t change surfaces too often, and get new shoes every 300 to 400 miles. For gymgoers, start with fewer sets of high-impact moves
and work your way up. Post-workout, roll out your feet on a lacrosse ball, perform the stretches at right, and reduce inflammation by icing the affected area for five minutes or so. (If you do have shin splints and the icing and stretches don’t help, then seek medical attention.)

2 Stretches to Keep your Shins Healthy

1. Seated Stretch

Sit on floor with both legs extended in front of you. Point toes forward and toward the floor, together or one leg at a time. Hold the stretch for 30 seconds.

2. Staircase Stretch

Stand with front of both feet on a step, heels overhanging step. Lightly hold railing or wall for support. Slowly lower right heel down, feeling the stretch along your calf. Hold about 30 seconds, then switch legs.