ADVERTISEMENTS for shoes that are meant to help people lose weight and add muscle tone have been ubiquitous this summer. “Get in shape without ever setting foot in a gym” is the trademark slogan for Skechers Shape Ups, which say they are designed to “firm calf and buttock muscles” and “reduce cellulite and tone your thighs.” Other manufacturers make similar claims for their products, which fall into a category called “functional footwear.” Generally speaking, these shoes work by creating a slightly uneven platform for the foot, theoretically forcing the leg, buttock and back muscles to exert more energy while walking or at rest. “You are always toning with EasyTone — even when you are standing,” Reebok says of its new line.

But can a pair of shoes really do all this? “Functional shoes do what they say they do, but there’s a huge variance in effectiveness between models,” said Louise Van Osten, a certified pedorthist in Ramsay, N.J., who owns a store in the Foot Solutions chain, which specializes in functional footwear.

Serious athletes often look down on these shoes, which are clearly not aimed at them, but at people who want to get in some exercise while they go about their busy lives. Kathleen Boyd, at left, a working mother from Eastchester, N.Y., is one such person. She takes brisk morning walks on the Bronx River Bike Path every other weekday for 45 minutes, and once each weekend for up to two hours, sometimes carrying weights. She tested five types of functional shoes, leaving her weights at home.

By SARAH TOLAND