Toning shoes are a class of footwear that are claimed to give the body and extra tone-up or workout. They have design features such as rocker soles that make the muscles work harder when using them. This is how they get the name of ‘toning shoes’. They are probably not as popular as they have been in the past but still widely used.
As to if the shoes actually achieve what they claim regarding the ‘tone up’ and its associated health benefits, it is open to debate and has been the subject of litigation. There are plenty of skeptical analyses of the shoes and there effects as well as some rational ones. Certainly a lot more research is needed to determine who would and would not benefit from such shoes.