I noticed the challenge just in swapping over to a Burn Sets XTrain video the other day (I posted about it in another forum). Faster pace, shorter rests - yikes! But I agree, i think change is good.
One other thing I might put out there as far as getting "bulky" goes - keep in mind the purpose of STS 2.0, at least, is hypertrophy as well as strength. The purpose of hypertrophy is to increase the size of your muscles.
Now, I'm not concerned any of us women will turn into hulking body builders, but yes, with hypertrophy your muscles get larger which then will add some "bulk" to our bodies.
As Deb mentioned, too, some of the other factors could just be water retention, diet, etc.
That said, I've definitely noticed my biceps getting bigger and my traps and shoulders are starting to get more defined. Can't really see my back, but I'm sure that's getting more muscular, too. All the while, I'm fitting into my pants a whole lot better now, which means I'm slimming down at my waist. And once again, all without tons of cardio - whodathunkit? (You'd think I'd NOT be surprised by this having known for years and years that more muscle = a higher metabolism, but I can't help it - I always get side-tracked by people saying cardio is the best for weight loss.)
