Feeling a stabbing pain near your heel when you step out of bed in the morning or when you get up from your desk? You might have developed plantar fasciitis, one of the most common foot injuries facing athletes today. “It’s the complaint that brings patients to a podiatrist’s office the most often,” says Megan Leahy, D.P.M., podiatrist at the Illinois Bone & Joint Institute in Chicago.

In fact, about one in 10 people will develop plantar fasciitis during their lifetime.

WHAT IS IT?

Plantar fasciitis is an inflammation of the plantar fascia, the ligament that runs along the bottom of the foot. Normally this tissue absorbs shock and supports the arch of the foot, but if it is overstretched or strained, small tears in the tissue can lead to inflammation, causing pain and discomfort—especially where the fascia meets the heel bone or at the arch on the bottom of the foot. Most of the time, plantar fasciitis won’t affect you during exercise—you likely won’t feel it until you get home from the gym and are walking around your house or when you get out of bed first thing in the a.m. And the more you walk around on it, the better it starts to feel.

HOW DOES IT HAPPEN?

Both athletes and sedentary individuals can develop plantar fasciitis, notes Leahy, since it can be brought on by weight gain, a sudden increase in intensity of activity, or even wearing wornout shoes. Runners are among those who suffer the most often, especially if they are suddenly adding more weekly mileage to their routine. But even frequent HIIT workouts can be to blame, since the pounding of some high-intensity exercises creates more stress through the foot. Other activities that place stress on heels can also create problems, adds Leahy.

But it’s not just your workouts that can cause trouble. Consider your footwear choices: “Constantly squeezing into narrow shoes can prevent the front part of the foot from moving,” explains biomechanist Katy Bowman, author of Whole Body Barefoot: Transitioning Well to Minimal Footwear. That means the smaller muscles of your feet, which should be helping to support the arch as well as dealing with the changing terrain as you walk, are weak, which in turn can stress the plantar fascia. Your toes may also be clenching as you walk, which can further stress the bottom of your feet.

BY KRISTIN MAHONEY