Slenamond, I am so glad you started this very interesting thread. I believe you will look leaner and not bulky. I, too, am 5'1", and, like you, looking leaner is what I am hoping for.
I pre-ordered STS in August, 2008 because I really need assistance with weight training, and I believe STS would provide gym-style results that I could achieve at home. I will begin when Cathe begins on 2/16. This entire thing is so exciting for me!
I have working out consistently for 2 yrs now and have lost over 50 lbs by personal coaching and living a Leanness Lifestyle, and have kept the weight off for over 1 year now, still counting. It is is difficult, but I'm learning that consistency is the key, of course along with eating clean and minimizing processed and fatty foods. My Coach recommended Cathe's DVD's to me.
Right now my goal is to burn more fat and develop more lean muscle. I went to a bodybuilding show with my Coach in November and was VERY impressed by the physiques I saw in the female fitness competition and my new goal is to get more muscular and leaner. Those women in the competition had HOT BODIES and did not look bulky or overly-muscular at all, and THIS motivated me a great deal! Now I can never see myself entering a contest of that sort, but I DO want to have more muscle!
Slenamond, I don't think you have to fear "bulking up". I am just learning that muscle is slimming, and we do not have the male hormones in our bodies to get bulky in the sense you may be speaking of. The reason that muscle is shapely, is because a pound of muscle takes 1/3 of the space in the body as one pound of fat.
A study published in 2000 in the Journal of Applied Physiology suggests that a woman weighing 150 lbs. at 33% bodyfat following a moderately strenuous training regimen focused on strength and endurance could gain about 2 lbs. of muscle in 6 months (or a 2% increase in muscle). I'm told that women in good physical condition can expect to gain 4-6 lbs of muscle in a year of consistent and progressive resistance training - not the rate of muscle growth to fear "bulking up"!
I am expecting to observe my first real muscle growth after 2-3 months of consistent and progressive resistance training, which is EXACTLY why I am excited about STS! I really love the way Cathe and the others in her videos look!
Also, remember, as we age we actually LOSE muscle, so resistance training takes on that much more importance for our health!
Good luck! I am certain you will find the results you want by eating clean and using STS!
Don't get me wrong - I think Cathe and the girls have awesome shapes but I am concerned that doing the STS is going to make me bulk up too much for my shape.
I am 5'1" (very short) and I think I build muscle pretty easy although I still have a some fat around those muscles that I need to lose! I want to look longer and leaner not bulky.
Are my worries un-justified?
Thanks for the input.
I bet we'll see some great results. 
