Kinesio tape, developed by Dr. Kenzo Kase decades ago, claims to provide muscle and joint support without restricting movement.  And it's so popular that Kinesio's product website advocates a particular taping technique which practitioners need to learn on a special training course. 4000 in Britain are qualified in this 'art' of Kinesiotaping, but the big question is, does it really work? 

Sure, the actual research doesn't show any real benefit but Kinesio has a response for that:  Science has simply not caught up to what the many customers already know.  Delightful!
Steve Harridge, a professor of human and applied physiology at King's College London, said many athletes appeared to be wearing tape even when they had no injury, possible hoping for some preventative or enhancing effect.

"It may be a fashion accessory, and it may be just one of those fads that come along from time to time, but to my knowledge there's no firm scientific evidence to suggest it will enhance muscle performance," he told Reuters.
That's why it's a placebo effect.  And athletes are driven a lot by subtle changes that make miniscule differerences yet in world competition make a difference between first place and last.  So wear 'em if you want, just don't convince gullible poor kids it will make them better athletes.

Scientists skeptical as athletes get all taped up by Kate Kelland, Reuters