As part of its routine monitoring program, NAD requested substantiation for certain performance and establishment claims made by Reebok International, Ltd. in print and Internet advertising for its EasyTone women's footwear. NAD inquired regarding the following claims: "It's the shoe proven to work your hamstrings and calves up to 11% harder and tones your butt up to 28% more than regular sneakers just by walking;" "Discover up to 28% more of a workout for your butt. And up to 11% more toning in your hamstrings and calves;" and "Better legs and a better butt with every step." Reebok supplied a study of five subjects who were randomly assigned to wear EasyTone shoes, regular walking shoes, or no shoes on an indoor treadmill at a freely chosen pace for five minutes. The study concluded that EasyTone shoe condition suggest the potential exists for both greater muscle force generation and greater metabolic energy expenditure.

NAD determined that this was a very small scale study both in number of participants and duration of the study, and therefore was not reliable or representative of the target audience. Additionally, NAD found that the study results that suggest potential toning were insufficient to support unequivocal claims that consumers will "tighten and tone with EasyTone" and "get a better butt." Therefore, NAD recommended that the claims be discontinued.

TIP: Companies should establish product tests that are statistically significant at a high confidence level so as to assure its results are reflective of the audience that is targeted by the claim.