Through the Paces: Testing Three Fabrics

Icebreaker

Consumers Digest enlisted researchers at Monfort Family Human Performance Laboratory at Colorado Mesa University in Grand Junction, Colo., last October to help us to evaluate whether performance-apparel T-shirts perform as advertised.

Exercise physiologists Brent Alumbaugh and Guy Leadbetter recruited six runners from CMU’s women’s cross-country team. We purchased three types of T-shirts—Asics’ Ecoline synthetic tee ($11), Icebreaker’s SuperFine Tech Lite wool ($36) and Under Armor’s Charged Cotton ($25).

Because these fabrics are designed to wick (or pull) away moisture and keep exercisers cool, our main objective was to find out whether any of these shirts keep exercisers cooler than the others do. We also recorded heart rate, perceived exertion and the weights of the shirts before and after a 30-minute run to find out whether one shirt absorbed more sweat than the others did. Alumbaugh and Leadbetter recorded skin temperatures by using a thermal camera.

Each participant completed four 30-minute runs on a treadmill in an 82-degree, temperature-controlled chamber. The only difference between the four runs was the apparel that the runner wore. In the control trial, runners donned only a sports bra and shorts.

The trials took place on different days, and the results were unequivocal: None of the shirts performed any better than did the others or even better than just wearing a sports bra.

No statistical significances emerged between the average skin temperatures throughout the trial, and none of the shirts retained more moisture, by weight, than did the others.

“All of the shirts seemed to be acting about the same,” Leadbetter says. “None of them can claim they’re better at wicking or keeping a person cool, but they’re all allowing runners to stay comfortable.”

Researchers measured skin temperatures on the front and the back of the torso at three intervals: before the run, 15 minutes in and then after 30 minutes. After 30 minutes, the skin temperature on the backs of our testers was slightly lower when they wore one of the shirts than when they wore only a sports bra. But temperatures on the front were slightly cooler with just the sports bra.

The results didn’t surprise Delia Roberts, who is a fellow at American College of Sports Medicine.

“It’s problematic to offload excessive heat, but for these women, who are probably accustomed to 30 minutes of running, [the length of this workout] is nothing,” she says. “You might not see any differences until you have a big enough physiological challenge where it becomes problematic to get rid of that heat load.” In other words, only athletes who push their body to its limit will notice a difference in performance when they wear this clothing.

The average skin temperatures on the back were lower overall than were the averages on the front. William Sands, who is director of Monfort, chalks up that difference to the fit of the shirt. A looser shirt is more likely to billow and allow for air flow, Sands says.

“The back has a little arch, so there’s more air space there, and when they run, the shirt sort of waves like a sail, creating some air flow that can facilitate evaporation,” and thus cool down the runners’ backs, Sands says.

All three shirts earned high marks for comfort. Study participants raved about the softness of the Charged Cotton, others told us that they preferred the lightness and breathability of the merino wool; the synthetic fabric got high marks for its light weight.

Granted, our evaluation was a small sample, and we examined these shirts in only one condition. But our experiment suggests that there isn’t much magic in any of these heavily hyped fabrics. The three manufacturers of the shirts in our study didn’t respond to our requests for comment by press time. Performance apparel might help you to stay comfortable, but we found no reason except fit or appearance to select one over the other. And we definitely didn’t find any reason to pay $25 for a performance-apparel T-shirt.