Laird Harrison

June 05, 2012

June 5, 2012 (San Francisco, California) — Runners are faster with "minimalist" shoes, but they can also injure themselves during the transition to this barefoot running style, researchers reported here at the American College of Sports Medicine 59th Annual Meeting.

One study showed that competitive runners shaved about 20 seconds off a 1-mile run by taking off their shoes. However, another documented 37 injuries in a group of 109 serious runners.

"If you do make this change, do so slowly and carefully," warned Paul DeVita, PhD, professor of kinesiology at East Carolina University in Greenville, North Carolina.

Barefoot running is becoming increasingly popular; advocates say it is more natural. Many shoe companies are making minimalist footwear that is lighter and less restrictive.

The presentation of research on barefoot and minimalist running attracted an avid audience at this meeting.

In one poster, 12 people ran on a treadmill for 6 minutes at 6 miles/h at a 1% grade. They ran the same trial barefoot and with shoes.

The runners consumed less oxygen when they were barefoot than when they were (oxygen volume, 34.5 ± 1.0 vs 36.1 ± 0.9 mL/kg per minute; P < .001).

In addition, when barefoot, pulmonary ventilation was lower (55.3 ± 4.0 vs 58.8 ± 4.2 L/min; P < .005), and strides became shorter (0.89 ± 0.02 vs 0.97 ± 0.01  meters; P = .001) and more frequent (181.0 ± 3.6 vs 166.4 ± 2.7 strides/min; P = .001).

Lead researcher Joel R. De Paoli, MS, from San Francisco State University, California, told Medscape Medical News that runners might move less efficiently when they wear shoes because their heels strike the ground first, breaking their forward momentum. "There is a likelihood that you land more on the forefoot when you run barefoot," he said.

In another study presented, conducted at Adrian College in Michigan, competitive runners tried Vibram Five Finger Bikila shoes. These shoes resemble gloves for feet and have a thin tread. They are supposed to simulate running barefoot while providing some protection.

The runners ran 1 mile faster with these shoes than with traditional running shoes (7.17 ± 1.04 vs 7.36 ± 1.06; P = .004). The researchers calculated that the weight of the shoe accounted for only 18% of the difference in speed.

A third study presented showed that many runners get hurt when they start running without shoes. In response to an Internet-based survey, 18 of 109 runners who were making the transition reported a muscle or bone injury, and 16 reported an injury on the bottom of the foot.

"I saw a lot of calf pain and tendinitis," lead researcher Allison Altman, PhD, told Medscape Medical News. She also documented a lot of blisters, but was surprised by how few people cut their feet.

Overall, the number of injuries was low, considering that up to 70% of runners have some kind of injury every year, she said.

Still, not everyone should assume they will run better without shoes, Christel Kippenhan, PhD, who studies biomechanics at Benmidji State University in Minnesota, told Medscape Medical News. She was not involved in any of these studies.

"You should not make everybody a forefoot runner," said Dr. Kippenhan, referring to the findings of De Paoli's team, which showed that barefoot runners are more forefront runners than conventionally shod runners.

Different running styles might work better for different people, she said. It could depend on the runners' weight, the size of their frame, and other factors yet to be determined. "I think we need more research to say one way or the other," said Dr. Kippenhan.

Dr. DeVita, Mr. De Paoli, Dr. Altman, and Dr. Kippenhan have disclosed no relevant financial relationships.

American College of Sports Medicine (ACSM) 59th Annual Meeting: Abstracts 1067, 2064, and 2063. Presented May 31, 2012.