The MBT or Masai Barefoot Technology are the first of the shoes in the toning shoes category and as such are the market leaders. The MBT shoes are designed to be unstable and create a toning or exercise effect.

MBT Resources:

http://www.clinicalbootcamp.net/do-mbt-shoes-work.htm

http://www.podiatry-arena.com/podiatry-forum/showthread.php?t=50133

http://www.podiatry-arena.com/podiatry-forum/tags/index.php?tag=/masai-barefoot-technology/

http://www.toningshoestoday.com/tag/mbt/

http://www.footstore.com.au/do-mbt-shoes-work/57/