I personally skateboard and snowboard as much as I can and I can guarantee you that it actually helps a lot when you can isolate your legs from your arms, and get the maximum out of both to get the best pop even on completely flat water.

GET LOADED
You have to think about the pop like a coiled metal spring. At first you push the spring back, building force as it's getting compressed, and then releasing it all of a sudden. The very first thing to do is squatting down slightly by bending you knees, engaging your quadriceps and buildin' up the explosive power. It's the polar opposite of the old skool windsurfing jump, where you absorb the ramp on take-off. If you did that, say on a wakeboard, you'd never get any height, whereas if you spring in and out of the pop you're gonna get boosted and make better use of the speed and power you have from the boat, momentum or whatever's got you up-to-speed.