Toning shoes, made popular by Sketchers, promote that they will tone your leg and buttock muscles and also lose weight. The shoes typically have a reversed arch. Instead of increasing your arch as is usually promoted by health experts, they do the exact opposite.
A reversed arch shoe is highly unstable and thus forces leg and buttock muscles to stabilize or balance you as you walk.
I have personally seen many people with increased tone as a result of walking with these type shoes. However, I have also seen the side effects.
Logically, there would have to be side effects. Most of us already know that it is natural and beneficial to have a normal arch. Many of us know that a lack of an arch is often the cause of foot pain. It can cause heel spurs, plantar fascitis and premature knee arthritis. Reversing our god given arch would have to be bad for us, wouldn't it ?
The reverse arch creates abnormal weight bearing and stress on the foot and leg.
Also, there is a normal sequence to gait as well. Every time we take a step, there is a normal order of muscles working together from heel strike through the foot, leg, thigh and buttock. That becomes abnormal with a reversed arch shoe, with potential consequences up to your hip and back.
I don't know of any health specialist that recommend these shoes.
There are class action suits against these type of shoes.
I've warned my clients for years about these type of shoes.
As usual, unnatural ways of losing weight and building muscles don't work in the long run.
The natural old-fashioned ways work just fine. Simply walking in normal shoes a few times a week works great.