Not for their muscles, but maybe for their minds.


Gold medalist He Zi wearing what appears to be k tape (Reuters).

If you've been watching the Olympics (or a bunch of other sports), you've probably seen some athletes wearing tape on various parts of their bodies. I first noticed some of the Chinese divers with tape on their lower backs. Other athletes have it on their shoulders or legs. What is this stuff? And how does it work? Actually, let's step back: Does it work?

It's called kinesio (or just 'k') tape. Athletes use the tape as a kind of elastic brace that they say helps relieve pain. The tape and technique were developed by Kenso Kase thirty years ago in Japan. Since then, many companies have developed similar adhesive tapes and they are in something of a marketing war.

Unfortunately, the evidence that k tape does much of anything is scant. One positive and relatively sophisticated trial found some shoulder pain relief in using the tape. But that study had some serious methodological problems. A metareview published earlier this year of all the available studies on the use of the tape was less positive. It looked at 97 papers on k-tape focusing on 10 studies that actually had control groups. Here's what they found:

In conclusion, there was little quality evidence to support the use of KT over other types of elastic taping in the management or prevention of sports injuries.

The tape, they continued, "may have a small beneficial role" for some injured people in certain situations, but "further studies are needed to confirm these findings."

I think that's all fairly technical language for: This stuff doesn't really do anything. So why might athletes continue to use it? Well, sometimes lying to yourself can lead to good things. Thinking you are better than you are (for whatever reason) might actually *make* you better than you are. Here was the conclusion of Joanna Stark and Caroline Keating's 1991 study, "Self-Deception and Its Relationship to Success in Competition": "The results were consistent with the proposition that self-deception enhances motivation and performance during competition."

Psychologist Roy Baumeister made a similar point in a widely-cited paper with an elegant turn of phrase. He claimed there was an "optimal margin of illusion" that allowed for the best human functioning. It might be good to think your vertical leap is greater than it is, but it's depressing to know just how earthbound you might be and dangerous to think you can fly.

And so, perhaps that's what k-tape does for athletes. It gives them the illusion of an edge, which might turn out to be all they need to have one. Just because lucky socks can't be empirically tested on a control group doesn't mean they don't matter. Just ask anyone who wears lucky socks.