A new study by researchers at Auburn University, Auburn, Ala, has determined that wearing thong-style flip-flops can result in sore feet, ankles and legs. Led by biomechanics doctoral student Justin Shroyer, the research team presented its findings during an annual meeting of the American College of Sports Medicine in Indianapolis.

“We found that when people walk in flip-flops, they alter their gait, which can result in problems and pain from the foot up into the hips and lower back,” Shroyer said. “Variations like this at the foot can result in changes up the kinetic chain, which in this case can extend upward in the wearer’s body.”

At the AU College of Education’s Department of Kinesiology, researchers recruited 39 college-age men and women for the study. The participants wore thong-style flip-flops, as well as regular athletic shoes, and walked a platform that measured vertical force as the walkers’ feet hit the ground. Additionally, stride length and limb angles were measured by video.

Under the direction of Wendi Weimar, PhD, associate professor of biomechanics and director of the department’s Biomechanics Laboratory, the research team discovered that flip-flop wearers’ steps were shorter, and that their heels hit the ground with less vertical force than when the same walkers wore athletic shoes. Wearing flip-flops, the participants in the study did not bring their toes up as much during the leg’s swing phase, which resulted in a larger ankle angle and shorter stride length; this is possibly because they tended to grip the flip-flops with their toes.

The research, however, does not suggest that flip-flops should never be worn. Their short-term benefits include helping beach-goers avoid sandy shoes and giving athletes post-game relief from their athletic shoes. In light of this, flip-flops are not designed to properly support the foot and ankle during all-day wear, and need to be replaced every couple of months, just like athletic shoes.

“Flip-flops are a mainstay for students on college campuses but they’re just not designed for that kind of use,” said Shroyer.

[Source: www.auburn.edu]