The windlass mechanism of the foot is an extremely important element in the normal functioning of the foot. It is the foots own natural arch supporting mechanism. The windlass mechanism consists of the plantar aponeurosis or plantar fascia. This powerful ligament attaches to the bottom of the heel bone and to the bases of the toes, so straddles the arch of the foot. During gait, when the heel comes off the ground, the toes flex, pulling on the plantar fascia and winding it around the metatarsal head (the ‘windlass’). This tightens the plantar fascia and supports the arch naturally. There are a number of different dysfunctions of the plantar fascia that can affect the windlass mechanism (see this).
What impact do toning shoes have on this windlass mechanism?
Quite frankly, they actually interfere with it. As most of the toning shoes use designs that incorporate a rocker bottom, the toes do not need to flex during gait, so the windlass mechanism is not ‘tightened’ up and the foot’s natural arch supporting mechanism is not engaged. In a lot of cases, this will not be absolute and there may well be some partial activation of the windlass mechanism. This will depend of the exact toning shoe used and the natural gait of the person using it, so it will be individual.
Is that a problem or not?
It might be or it might not be. It is going to depend on a lot of other factors. It is going to have to be one of trade-offs. For example, what are the benefits of wearing the shoe versus the negative of the windlass mechanism not working. It could well be that part of the ‘toning’ effect for the muscles being made to work harder comes as the muscles need to support the arch more as the windlass mechanism does not support it. There is certainly no research that has looked at the effect of the toning shoes on the windlass mechanism or the consequences of the potential interference with it.
However, those with problems of windlass dysfunction, may need to approach the use of toning shoes with caution as any worsening of their windlass mechanism function could potentially be problematic. More can be found on the problems of the windlass mechanism at Run Research Junkie.