I bought these for my husband after he got jealous about the pair I bought myself from Macy's.  These are some of the only flip flop style shoes approved by whatever the podiatry board is, and my husband has severe low back problems, so we don't mess around with bad shoes.

My husband loves wearing these and he has never worn mandals or flip flops before.  These don't look too silly when he wears them with his shorts and they are comfortable to wear all day.  I am not 100% sure I see any physical improvement in his tone, or mine for that matter but I guess the improvement might be subjective.  I don't think anyone can expect to buy these shoes as a replacement for a good work out but they would be complimentary to a healthy lifestyle overall.