I just joined curves and three sessions in I can feel I have worked my muscles(well stiff)...It's the effort you put in that makes the difference. I also walk to and from work and around London so getting an overall work out...But curves is great and everyone seems nice and it is a two minute walk from my house...I never have to wait for machines ...I love the bit inbetween the machines where you jump or walk on the spot until the next machine..I normally dance like a maniac because the music is good...and the fact that it is only half an hour means I get to go after work then go home and cook dinner and eat at a reasonable time instead of how I used to at other gyms