Katherine suffers from rheumatoid arthritis in her hands, and has found that wearing tight bracelets or wrapping fingers with tape often reduces the amount of pain she feels. My uncle used to wear a copper bracelet, presumably for the same reason. My mother wraps her legs with compression bandages when her varicose veins cause her legs to hurt. She would also similarly wrap our legs as kids when we had growing pains. Athletes have been known to compress injured areas with tape or support braces. In the Olympics, volleyball players were seen with taped fingers and shoulders. In the far east, acupuncture was developed to relieve pain. All of these treatments for pain have one thing in common. They involve touch stimulus of the area at or near where the pain exists.
The subject of pain relief was restimulated for me last fall when I was introduced to the gate control theory of pain in a neurobiology class. At the simplest level, the notion is that normal touch known as somatosensation can interfere with nociception, the sensation of pain. This made me rethink why Katherine found pain relief from wearing bracelets. This prompted me to think further on all of the similar methods of pain control I had encountered as well as the tendency for someone that is exerting themselves to not feel low level chronic pain. From an evolutionary perspective it seems reasonable that feeling pain is generally not good when demands are being placed on the body. People have been taking advantage of this characteristic ever since.
The original theory was developed in the 60s when it was well accepted that pain was part of the somatosensory system. Now, the there are those that think nociception is exclusively part of the interoceptive system, also known as the visceral or autonomic nervous system. This is the system that helps us to maintain the environmental balance in our bodies. It tells us to eat and what to eat, drink, sleep, breathe, warm up by shivering and finding warmth, to cool down by sweating and seeking shade, and much more. It basically maintains our bodies. It does this in part by producing input into our higher thought through emotion and is affected by emotional feedback.
This leads me to an interesting experiment published in 1997. If 1/3 of the neurons leading into a section of the somatosensory cortex(SI) of a monkey were visceroreceptive, it is clear that there is some overlap. Considering that there isn’t extensive communication between the SI and emotion centers such as the insula, it seems likely that the inhibition of nociception by somatosensory probably occurs in the spinal cord as the gate theory suggests.
The next question of importance is what is the mechanism at work with Kerri Walsh’s Kinesio tape? They, like many before them, attribute their success to a special property of their proprietary method. In this case, they think it is from improved circulation. They even have a published study. From looking at the “sham” treatment on the third (390) page, it is evident that they aren’t differentiating their treatment from the gate control theory of pain. The “sham” isn’t producing tension, thus it isn’t significant stimulus to have gate control kick in.
I would go further and say that this is a poorly performed study for two reasons. First, their “sham” treatment is likely to not produce the placebo effect. A reasonable person might be inclined to laugh at such a crude tape job. Second, if I wanted to show a more significant improvement from one treatment over another, I would assign that treatment to more seriously injured individuals. If one looks at table 1 on the fifth (392) page, the KT group is the more injured group. My opinion of JOSPT is not high to say the least.
At the end of the day, the point is that Kinesio Tape is likely just a new incarnation of a trick that is probably thousands of years old. The difference is that maybe we are approaching the day where we will understanding the underlying mechanisms.