A few more volleys have been fired in the escalating Compression Garment Wars. Australian researchers have just posted a new study in the Journal of Strength and Conditioning Research that gives a thumbs-up to whole-body compression garments for the repeated-sprint activity typical of soccer and other field sports. Meanwhile, researchers at Indiana University have reached the opposite conclusion about the ability of compression leggings to help running endurance and jumping ability.
First the Australian study: they used full-body Skins compression suits — yep, that’s long sleeves and full leggings. The test was a treadmill simulation of the demands of a typical soccer game, with a mix of walking, jogging, running and sprinting for 45 minutes; the more distance you cover, the “better” you’ve done. They had volunteers do the test twice, once with Skins and once without, and found a “moderate strength likely improvement” in distance covered (5.42 vs. 5.88 km), and similar “likely” improvements in muscle oxygenation, but no changes in heart rate and VO2.
(This “likely” business means they didn’t find statistically significant differences — not surprisingly given the small sample size — but still have reason to believe that the difference is big enough to matter to athletes, if I understand correctly.)
Now, I believe the oxygenation stuff. No doubt that if you cram yourself into one of these suits, you are affecting your physiology in some way. (For example, as the authors note, similar previous studies have found that — surprise, surprise — full body suits “may have some thermoregulatory effects.” In other words, they make you hotter.)
But the question is, are these small physiological effects translating into meaningful performance changes? On the surface, you might think this study answers yes. However, it absolutely boggles my mind that anyone could write a paper like this and not even mention the possibility of a placebo effect. Really? You put one group in a $100 spacesuit, the other group in a cotton undershirt, and you’re surprised to see an 8% improvement in a very “soft” measurement with a 12% error bar? And then you conclude, with a straight face, that these things will make you a better soccer player because you’ll have more oxygen in your lower limb muscles, even though the increased speed was only seen during the jogging portions of the test and not the fast running or sprinting?
Okay, so on the other hand, two new studies from Indiana. One tested lower leg compression garments on 16 distance runners, and found no changes in muscle oxygenation, running economy, or mechanics. The other tested the upper thigh compression shorts that basketball players love, using three sizes (Goldilocks style: one that was a size up, one that was a size down, and one that was just right). Vertical jump was the same in all three cases.
The most interesting point in the Indiana studies may be the following:
Although overall the study found that the compression garment had no effect on running mechanics and economy, there was some variation. Four subjects had an average of greater than one percent increase in oxygen consumption — their economy worsened — while wearing the compression garment. However, four other subjects experienced a greater than one percent decrease in oxygen consumption — their economy improved — while wearing the compression garment. Laymon had her subjects complete a subjective questionnaire about their feelings toward compression garments before completing their tests. It turned out that the subjects who experienced improvement in their economy were more likely to have a favorable attitude toward compressive wear and believed that by wearing the compressive garment their racing would improve.
“Overall, with these compressive sleeves and the level of compression that they exert, they don’t seem to really do much,” [researcher Abigail] Laymon said. “However, there may be a psychological component to compression’s effects. Maybe if you have this positive feeling about it and you like them then it may work for you. It is a very individual response.
Two important points here. First, it looks like if you believe they work, then they will. (See my post last week confirming that superstitions boost performance!) Second, there’s significant individual variation. As I said at the top of this post, there’s no doubt that compression does something to the body. But these studies, and the others that continue to pile up, do nothing to convince me that we’ve figured out how to harness those effects in a useful way (at least for performance enhancement — recovery from soreness looks a little more solid at this point).