What causes it: Inflammation of the plantar fascia, a thick band of tissue that runs along the bottom of your foot from the heel to the toes.

CNN: Why your feet hurt

More than 2 million Americans suffer from debilitating heel pain stemming from inflammation of the plantar fascia, a fibrous band of tissue that supports the arch of the foot.

FORBES: The Big Hurt

He was ruled out for the third time in four games after an exam Thursday of his strained heel also revealed a plantar fascia tear in his right foot.

WSJ: Nuggets beat Nets to win 18th straight at home

Stress fractures, tendonitis or plantar fasciitis, a hard-to-heal tissue inflammation that feels like needles driven into your foot, are likely to result for runners who dash out the gate barefoot without gradually working up to it.

CNN: Running debate: Bare or in shoes?

"The plantar fascia is in a relaxed position when you're sleeping, " says Jacqueline Sutera, a podiatric surgeon in New York City.

CNN: Why your feet hurt

Barefoot runners risk getting athlete's foot and plantar warts, says Stephen Morse, a professor of epidemiology at Columbia University's Mailman School of Public Health.

WSJ: Barefoot Jocks Keep Gym Members on Their Toes

"I know it's hard to come back from, but I'm on it a lot earlier than I was last time, " said Noah, who missed 18 games with plantar fasciitis during the 2009-10 season.

WSJ: Bench carries Nets past Bulls, 93-89