The United Kingdom's Advertising Standards Authority has banned print and TV advertisements for Reebok Eastytone Curve shoes, saying research the manufacturer submitted was either too limited or failed to substantiate its claims that the shoes improves muscle tone. Reebock was ordered to stop running the ads.

The magazine ad featured headline text that stated “Reetone [sic] with every step. Get up to 28% more of a workout for your bum. And up to 11% more for your hamstrings and calves”. Underneath was an outline of a woman with the text “28% gluteus maximus”, “11% hamstrings” and “11% calves” written next to the corresponding parts of her body.

The TV ad featured women walking, dancing, jumping, spinning around and standing, with the camera fixed on their bottoms and legs; all were wearing trainers. The voice-over stated “Reebok EasyTone. Helps tone legs and bum more than regular trainers. Reebok EasyTone with balanced ball inspired technology. Better legs and better bum with every step”.

The U.K's Advertising Standards Authority received two complaints challenging the efficacy claims for the product and alleging they were misleading and could not be substantiated.

Reebok submitted third party studies they had commissioned to support their claims, but the ASA disagreed.

“Because we considered that we had not seen robust, scientific evidence to support the efficacy claims made in the magazine ad (a) or the TV ad (b), we concluded that the claims had not been substantiated and were therefore misleading,” reads the ruling by the ASA. “The magazine ad (a) must not appar again in its current form and the TV ad (b) must not be broadcast again in its current form.”

The ASA considered that the claims “Reetone with every step. Get up to 28% more of a workout for your bum. And up to 11% more for your hamstrings and calves” in ad (a), and “Helps tone legs and bum more than regular trainers … Better legs and better bum with every step”, alongside the images of the women doing different activities, in ad (b), would be understood by consumers to mean that wearing EasyTone trainers regularly, during everyday activities, would result in a noticeable improvement in muscle tone, which would continue over time.”