Seeking better, stronger bodies, some exercisers squeeze themselves into compression clothes.
These snug-fitting socks, shorts, tights or shirts, which squeeze muscles as tightly as sausage casings, are said to improve performance during exercise and speed recovery afterward.
But a new study and several reviews of relevant research raise questions about whether the garments really function as expected and help people to exercise better and, if they do, whether it is the clothing or people's expectations doing most of the work.
The rationales for wearing compression clothing are logical enough.
"The garments supposedly increase blood circulation and thus oxygen delivery for improved sport performance," said Dr. Abigail Stickford, a postdoctoral researcher at the Institute for Exercise and Environmental Medicine at the University of Texas Southwestern Medical Center in Dallas, who led the new study of compression clothes.
The clothes also are thought to refine proprioception, which is someone's sense of how the body is positioned in space. Better proprioception should, in theory at least, improve the efficiency of movement and reduce the number of muscles that need to be activated, making exercise less tiring.
Meanwhile, the clothes also are believed to reduce
fatigue and soreness after exercise by literally squeezing the muscles with a kind of no-hands massage and, by increasing blood flow to muscles, helping flush out unwanted exercise-related biochemicals.
The evidence to support such benefits has been largely anecdotal, however.
So for the new study, which was published in January in The International Journal of Sports Physiology and Performance, Stickford, then a doctoral student at Indiana University in Bloomington, decided to perform a simple test of compression gear.
She rounded up 16 competitive male distance runners, some of whom regularly wore and swore by compression clothes, although most had not worn the clothing before. She equipped the runners with monitors and masks that would measure their gait, oxygen intake and other variables, and had them run on a treadmill at three increasingly swift speeds.
Then she had the men slip on calf compression sleeves.
The men repeated the treadmill tests.
Had the compression sleeves functioned as expected, the men should have used less oxygen and been more biomechanically efficient when wearing the sleeves, Stickford said.
But as a group, they were not. She found no statistically significant differences in their running efficiency or biomechanics when they wore the sleeves and when they did not.
"Based upon the results of this study, lower-leg compression sleeves are unlikely to improve endurance running performance," Stickford said.
Other studies of compression clothing have produced similar results.
FAVORABLE RESULTS
A particularly interesting 2013 study, for instance, showed that compression shorts do not increase blood flow to leg muscles after exercise, although enhanced blood flow is supposed to be one of the primary means by which the clothes speed recovery. Instead, the scientists found, exercise itself greatly increased post-exercise blood flow to muscles, but compression shorts did not further augment that flow and in fact reduced the amount of blood reaching the deepest leg muscles.
Still other studies, however, have been more positive about compression.
A review of more than 30 studies of the effects of compression clothing in sports performance and recovery, for instance, determined that "compression clothing may assist athletic performance and recovery in given situations." Those situations involve sports such as basketball or track and field that require explosive sprinting and leaping, although athletes in other sports, including weight training, have reported feeling less sore if they wear compression clothes than if they don't, the review found.
How the clothes work, though, remains mostly baffling -- and may owe something to input from the mind. "We can't blind people" in exercise studies about whether they are wearing compression garments or not, said Dr. Billy Sperlich, a professor of exercise science at the University of Wurzburg in Germany, who led the study of blood flow and also was a co-author of the recent review.
So people's expectations of what the clothes will accomplish may color their results.
Which does not mean that any resulting benefits are not real, Sperlich said. "Since beliefs are strong performance enhancers, I would recommend compression clothing to persons who believe in the performance-enhancing effect," he said.
There are caveats, though, for anyone who is considering wriggling into compression garments, he said. The clothes do need to fit correctly, he said, which means tightly.
"In our studies, about 50 percent of the subjects like compression, 30 percent are indifferent and 20 percent don't like the compression at all," Sperlich said.
The clothes also need to be worn for several hours after strenuous exercise sessions, he said, if they are to improve recovery, raising delicate issues about odors.
The good news is that no study to date has found any negative physiological effects from wearing compression clothing, Stickford said. So if you do decide to experiment, "there is not much to lose besides 40 dollars or so."
ActiveStyle on 03/02/2015