Hi /fit/.
I don't frenquently lurk here, but im in need of your help now.

I want to become a martial artist, i have decided that i want to do this as a hobby and a way of life. I've been training wing tsun for the past 7 months and i have already a few years of boxing and judo.

My problem is as follows. I'm a short dude 1.65 tall (5.5f) and i have a tendency to become buff fast if i lift.
So i am wondering what would be the best way to gain functional strenght on the whole body, without growing "bigger", my main concern with becoming too buff is speed, and flexibility those two things are specially important for me because they are my sole advantage against someone that has a bigger reach than me, also in my kung fu style (wing tsun), being capable of producing relaxed strenght from structure rather than musculature is important so i can't be tense, if i'm tense i end up on the floor.

If anyone can answer this i would be happy, thanks in advance lifting gods.
also excuse my poor english, is not even my second lenguaje.