Fat Monkey Statue, Sao Paulo, Brazil

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
Along the east coast of the US so called flip-flops are gaining popularity in being referred to as "Zories" zories are also known as jandals in New Zealand, infradito (between-toes) in Italy, chappal, Hawaii chappal, Qainchi (scissor-like) chappals in India and Pakistan, thongs in Australia, France, claquettes, Canada, slip-slopers (or just slopers) in South Africa, go-aheads in the South Pacific, ojotas or chancletas in Argentina,chanclas in Spain, sereppu or bata in Sri Lanka, chancletas or sandalias in Mexico, Central America and South America, japanke (lit. Japanese) in Croatia, Serbia and Montenegro, japonki (lit. Japanese (women)) in Poland, вьетнамки / v'yetnamki (lit. Vietnamese (women)) in Russia, chinelos in Brazil, kafkafim (כפכפים) in Israel, sayonares in Greece, tsokara in Greek Cyprus, vietnámi papucs (lit. Vietnamese slippers) in Hungary, žabky (lit. small frogs) in Czech and tsinelas or chinelas in the Philippines; parmak arası terlik(between toes slippers) in Turkey. In parts of Texas they are known as clam diggers because of the way they flip sand on a beach. In Hawaii, the Philippines, and several other places around the world, they are called "slippers".