I did a bit of research into Toning Shoes, which seemed to be all-the-rage at the time. I mean, who wouldn't want a toned bum and legs?! After reading various articles though, it became apparent that the toning effect was pretty dubious. However, there were a couple of sites I found such as http://best-earth-shoes.blogspot.co.uk/2012/08/how-toning-shoes-can-easily-decide-to.html which suggested some toning shoes could reduce stress on the knee joints and reduce back soreness.
I thought I'd give them a go, and tried a couple of different brands.
I found these type the best. They have air cushions in the sole, which makes every step quite bouncy. Also, I didn't feel unstable in them, unlike other brands. I would totally recommend them for anyone who feels like they're dragging their legs. Having that extra lift with every step has meant I get fatigued slower, and I've felt my stride getting longer.
However, there are questions about their safety, and there's a law firm in the US that specialises in toning shoes accidents http://www.toningshoesinjury.com/ (!), but I took this with a pinch of salt. After all, in the US it seems normal to sue someone for every little accident. Plus, I don't wear them often, so I can't see why they would have any long-term side effect.