but i don't know wat to do for resistance training
Good news brother, what helps with MMA, will for the most part help for parkour.
We recommend either gymnastics holds + squats and deadlifts, or
Starting Strength. Decide whether you want to use weights or not, then read up on it a bit. If something doesn't make sense, come back & ask.
Since you're already doing a lot of skills training, I'd recommend focusing on strength for now. You should be able to work endurance well enough during MMA, BMX, and parkour. It's much harder to gain strength doing those things. Once you get strong, you can back off to maintenance levels and strength and push endurance if you'd like. Work strength though. Imagine being a bantamweight fighter that can squat the body weight of a heavyweight.
Read the sticky and check out
Eatmoveimprove like the others suggested.
