Kiwi experts are not surprised a manufacturer of toe-sock running shoes has revealed there is no scientific proof that wearing its product has added health benefits.
Vibram, the makers of FiveFingers running shoes which are designed to mimic the effect of running barefoot, settled a $4.35 million class action lawsuit in the US over the false claims.
As part of the settlement, customers who purchased pairs of the shoes may be eligible for a partial refund and the firm has promised it will not make any more claims without scientific evidence to back them.
The firm continues to deny wrongdoing, but as part of the settlement agreed to remove claims that the shoes are effective in strengthening muscles or reducing injury.
"Vibram will not make ... any claims that FiveFingers footwear are effective in strengthening muscles or preventing injury unless that representation is true, non-misleading and is supported by competent and reliable scientific evidence," the federal settlement said.
Auckland podiatrist Simon Speight said the legal action did not come as a surprise as popular theories promoted structured shoes that cushioned the feet for protection. "They are consistent with harm-causing features of footwear," he said. "Running shoes by their very nature of design are there to prevent injuries from happening and to improve performance.
"All of our theories for the most part restrict movement in the foot, that's what tends to help."
Shoe Clinic director Neville McAlister said his nationwide chain of stores have never stocked the products on advice from podiatrists.
"The podiatrists that we deal with end up getting a lot of business through [toe-shoes] because people go running in it and get injured."
He said fans of the shoes claimed they were mimicking the physical conditions of "the evolution of man".
"In the cave days they ran on clay or dirt, they weren't ever running on concrete which has no shock absorbing properties and sends jarring up the legs.
"People also didn't sit in an office chair like they do now which tightens up the hip flexors."
He said most people needed some kind of specialised support from their shoes, which was achieved through cushioning and structure.
Vibram is known for its shoe soles, especially for hiking footwear. It first produced the five-toe "minimalist" shoe in 2006 and big brands Nike, Adidas and New Balance followed suit with similar designs.
In 2007, they were named by Time magazine as one of the year's best health inventions, and a 2009 book, Born to Run, by Christopher McDougall, helped enhance the popularity of the shoe.
Scarlett Johansson, Danny Glover, Kate Hudson and James Cracknell have all experimented with the shoes.
- additional reporting by Harriet Alexander from the Sunday Telegraph