US shoemaker Skechers is to pay $40 million to settle claims that it deceived consumers by suggesting its sports shoes could help tone their butts and lose weight, officials said Wednesday.

In an agreement similar to one last year against Reebok, the (FTC) said purchasers of the California-based firm's Shape-up, Resistance Runner, Toners and Tone-up shoe ranges can apply for refunds.

The Shape-ups ads featured stars including Kim Kardashian and Brooke Burke. In one which aired during the 2011 Super Bowl, Kardashian was shown dumping her personal trainer for a pair of Shape-ups.

"Skechers' unfounded claims went beyond stronger and more toned muscles. The company even made claims about weight loss and ," said David Vladeck, director of the FTC's Bureau of Consumer Protection.

"The FTC's message, for Skechers and other national advertisers, is to shape up your substantiation or tone down your claims," he added.

California Attorney General Kamala Harris added: "Consumers shouldn't be duped into paying more for products with false promises of weight loss and other benefits."

The settlement was part of a wider agreement resulting from an investigation involving 44 states and the District of Columbia.

Last September, sportswear giant Reebok, a unit of the German group Adidas, agreed to pay $25 million in customer refunds to purchasers of its EasyTone and RunTone .