Grass Flip Flops

In 2008, Auburn University researchers found that wearing thong-style flip-flops can result in sore feet, ankles and legs. The research team, who presented their findings at the annual meeting of the American College of Sports Medicine in 2008, found that flip-flop wearers took shorter steps and that their heels hit the ground with less vertical force than when the same walkers wore athletic shoes. When wearing flip-flops, the study participants did not bring their toes up as much during the leg’s swing phase, resulting in a larger ankle angle and shorter stride length, possibly because they tended to grip the flip-flops with their toes. This repeated motion can result in problems from the foot up into the hips.
Regional names
In India, flip-flops are referred to as "chappal." Along the east coast of the US flip-flops are sometimes referred to as zories. They are known as jandals in New Zealand, thongs in Australia, Plakkies and slip-slops (or just slops) in South Africa, and go-aheads in the South Pacific. In parts of Texas they are known as clam diggers because of the way they flip sand on a beach. In Brazil called chinelo, sandália or Havaianas. In the Philippines they are mostly called tsinelas. In Hawaii and several other places around the world, they are commonly called slippers. In Greece they are known as sayonares (σαγιονάρες), probably from the Japanese word sayōnara, that means goodbye, because of their Japanese origin. In Poland they are commonly called japonki which indicates their Japanese origin. In Russia and Ukraine they are sometimes called lapti. Americans call them flip-flops.