Probably the athlete who has stimulated the most questions is Kerri Walsh, the star beach volleyball player who, along with Misty May, is the favorite to win the gold medal in beach volleyball. She has been playing with kinesiotape on her shoulder throughout the Olympics, although she notably did not have any on last night during her semifinal match against Brazil.
Before researching the answer, my anecdotal experience from residency training was that while kinesiotape is limiting in it's ability to actually restrict motion, but it is useful as a proprioceptive cue. The theory behind this is sensory substitution. In this case, it is substituting tactile sensation to compensate for inadequate proprioception, which I will elaborate on below.
Proprioception refers to the ability to know where your body is in space. For example, if you close your eyes, you can flex and extend your elbow and know the position of your elbow- that's proprioception. Proprioception is important in sports activities, because to function at a high level, an athlete needs to properly place their limbs in a location to optimally contract their muscles to deliver a movement quickly and forcefully. A few examples where this can be especially important:
1. The knee- when an athlete lands, the knee needs to be optimally located to allow for smooth tracking of the patella (knee cap) along the groove of the femur (thigh bone). Improper positioning (usually of the femur) can cause abnormal tracking of the patellofemoral joint, causing patellofemoral syndrome.
2. The shoulder- the shoulder is one of the most mobile joints in the body, and requires an intricate interaction between multiple muscles (including the rotator cuff muscles, serratus anterior, trapezius, levator scapula, and several others). A typical pattern may include using the rotator cuff muscles to pull the head of the humerus into the glenoid fossa of the scapula (shoulder blade), co-contracting the serratus anterior and lower trapezius to position the scapula into the optimal position, and then contracting the teres major and latissimus dorsi to position the humerus throughout the range of motion. From just that description, one could see how the coordination of the muscles at the optimal time and in the optimal proportions could be challenging.
So, how does kinesiotape theoretically help? Well, the tape is a semi-rigid tape that stays relatively loose and comfortable when the joint is moving throughout the proper range of motion, but becomes uncomfortably tight when moving the joint outside of that ideal range, creating tension on the skin. This helps use the tactile sensation of the pulling on the skin to substitute (or reinforce) the proprioception of the joint. In combination, this helps reinforce the optimal positioning and movement of the joint.
So, back to the readers question- does it work?
Anecdotally, it is a useful reminder to maintain posture. I've used it experimentally, just for kicks, to see if I could remember to keep my back straight while lifting. It did help, although it could also be annoying every time I tried to sit down. So, there is the balance between reminding one of proper positioning, and an annoying tugging of the skin.
What is the evidence?
A search on pubmed on the term "kinesiotape" yields one article:
Res Sports Med. 2007 Apr-Jun;15(2):103-12.This article looked only at range of motion, not the more complicated question of athletic performance. It found it helped to some extent.
The effect of kinesio taping on lower trunk range of motions.
Yoshida A, Kahanov L.
I then checked out the kinesiotape website: http://www.kinesiotaping.com/
To their credit, they have a grant process available, where they will supply tape to interested researchers to help conduct studies. They also have links to a few studies that are germane to the reader's questions:
J Orthop Sports Phys Ther. 2008 Jul;38(7):389-95. Epub 2008 May 29.This study looked at 42 participants with presumed rotator cuff pain, and randomized them into 2 groups, one of which used kinesiotape. The results aren't overwhelming, but the kinesiotape group did have some increased range of motion.
The clinical efficacy of kinesio tape for shoulder pain: a randomized,
double-blinded, clinical trial.
Thelen MD, Dauber JA, Stoneman PD.
There are a few other studies cited for other conditions listed on the website.
So, back to the key questions:
1. Does kinesiotape work, in general?
Maybe. I don't think the evidence is overwhelming, but absence of evidence is not evidence of absence. I think it probably does offer some sensory substitution that is useful as part of an integrated physical therapy program in training an athlete to use their joint through an optimal range of motion.
2. In the specific case of Kerri Walsh, does it help?
Maybe. She's been playing pretty well, although it is interesting that many of the teams have aggressively challenged her defensively. Also, she ended up pulling it off for her semifinal match against Brazil. With an athlete like Kerri Walsh, who may be the best ever in her sport, it is difficult to attribute any one component of her success to any one intervention. Probably the largest benefit is providing her the confidence to play all-out.
3. Would I prescribe it?
Yes. I have prescribed it. My closest friend from training (the late Jim McLean) used it regularly for his patellofemoral syndrome, and he attributed it to being of the keys to him running marathons again.
Please share with me your thoughts.