If you’ve ever trained for a marathon or long-distance race, you know the closer you get to race day the gnarlier your feet get. Aesthetics aside, mangled feet can seriously hinder your performance—especially blisters.

“Multiple methods of blister prevention have been tried [in the past],” says emergency medicine physician Grant Lipman, MD, “including powders, antiperspirants, lubricants, tapes and adhesive pads.”

Unfortunately none of these methods are able to hold up. Lipman saw this first-hand when he was working as a doctor for endurance athletes running 25 to 50 miles a day. So, with his own trial and error, nearly 40 years of blister prevention research, and anecdotal evidence from military doctors treating recruits, Lipman and Stanford University Medical Center hit the ground running to find and test a reasonable solution that withstands serious mileage.

In his study, published in the Clinical Journal of Sport Medicine, Lipman and his colleagues recruited 128 runners participating in the 155-mile, six-stage RacingThePlanet ultra marathon event, which spans the Gobi Desert and arid landscapes across Jordan and Madagascar. Trained medical assistants applied paper tape to just one of the runners’ feet—chosen at random—so the untaped areas of the same foot served as the control.

The tape was applied in a single layer to participants’ blister-prone areas or, if they had no blister history, to randomly selected areas on the foot before the race. The medical assistants followed the runners for 155 miles over seven days and reapplied tape over the course of the race.

For 98 of the 128 runners, no blisters formed where the tape had been applied, while 81 of the 128 developed blisters on the untaped areas. Seriously—it worked that well.

“It’s kind of a ridiculously cheap, easy method of blister prevention,” Lipman said in a press release. “You can get it anywhere. A little roll costs about 69 cents, and that should last a year or two.”

Better yet, because it’s also used as surgical tape, it’s only mildly adhesive so if you do get a blister, the tape won’t tear open the skin.

Have an obstacle course race, IRONMAN, or mountain ultra marathon coming up? Take care of your feet so you can make it to the finish line blister-free. (And read how this training tip can give you a leg up on the competition.) And, even if you’re not training for such a Hurculean feat, taping your feet can save you serious discomfort during trail runs, hikes, and long runs too.