Yarg! said:
I work a body part once every 7 days... Then again, I do lots of reps/sets, so it all balances out at the end. I seem to get alot of good results doing this, and working out the fast and slow twitch fibers seperately (heavily modified 5 by 5 ). I love this technique, and I will stick with it untill I find something better.
There ya go.
I'm on a cliche roll here so I'll continue: some like to say pain is weakness leaving the body.
In a similar vein, we could say weakness/smallness is a disease, and training is the cure
I often think of training like medicine. Medicine's something we can measure (dose); training's measurable too, w/ sets, reps and so on. We can take too much or too little medicine, just as we can over or undertrain.
So in effect, what you are doing is giving yourself a very large dose 1x/wk. instead of a moderate dose 1.5x/wk., small doses 2-3x/wk., etc.
Generally, I do think that a number of smaller doses work somewhat better than singularly huge ones. I mean, once you've done two sets of deep, high rep squats to failure, then 2-3 heavy sets of SLDL or Romanians, you've given your thighs plenty of stimulation to grow.
At that point, would throwing in leg extensions et al. really yield much more growth? And since taking a higher dose risks [or is] ODing, it'll be that much longer before your "bloodstream's" ready for another dose--that much longer before you can grow again.
That's just food for thought, really; it's always nice to consider the possibilities one has at hand, and it heartens me to hear people ask "why?" a lot. (Yep. I don't have kids yet

LOL. That'll show me!

)
Anyway, that's also a rather moot point in your case, since what you're doing's working well (good to hear, btw). I think in the long run, the differences between training something 2x/wk. vs. 1x/wk. isn't necessarily huge, anyway. I gained well training each bodypart once per week myself.