WASHINGTON — Suddenly, the Ice Bucket Challenge doesn’t seem so silly.

The newest viral challenge asks the question: Can you reach around your back and touch your belly button?

It started in China on Weibo — the Chinese equivalent to Twitter — and has been mentioned hundreds of millions of times on both microblogging sites.

Most of the participants are young female users.

Fitness, nutrition, and psychological experts worry that focusing on a stunt that encourages being extremely skinny is potentially damaging to a person’s psyche.

What makes matters worse — being skinny doesn’t make the #bellybuttonchallenge any more doable.

Longer arms and flexibility increase a person’s ability to perform the task, as much as having a small waistline.