Toning or unstable footwear were all the rage in the 2000's. The promotors of those footwear used to make unbelievable claims for the shoe. claims varied from enabling weight loss to getting rid of cellulite to sculpting the buttocks to fixing low back pain. The shoes were built with a rocker on the sole aimed at increasing muscle activity to obtain those presumed benefits. Unfortunately, the evidence did not stack up and there was a lot of lawsuits from disgruntled consumers and many manufacturers were forced to negotiate multi-million dollar pay outs with the Federal Trade Commission.
While all that is in the past you can find some of these types of footwear available and they still do have some support from those people who are knowledgeable about the footwear. Toning shoes do alter the way that you move and for some people that could potentially lead to an improvement in some things like low back pain. Equally, it could make some people with low back pain feel worse. There is a lot of effort being geared towards studying precisely what the footwear actually do and precisely who will benefit from them and who might be hurt by them. Different people are going to respond in different ways to them.
Foot doctors seem to especially like these types of toning shoes due to the type of patients that they see. The rocker sole nature of the shoe means they are particularly great for those with a sore great toe joint, as with these shoes the big toe doesn't have to move as much. However, while that might be useful for that joint it does put more force on the ankle joint so could possibly create or make worse issues at the ankle joint. It was issues like this that led to the litigation issues in the past and need to be taken into consideration by anyone suggesting or using these shoes. They do have their uses and they may help for the right people with the right condition.