Eluding or minimizing the effects of the POW Block is probably one of the best tricks you can master when racing WFC or Grand Prix mode, especially when you start to try to get Stars on 150cc or Mirror Mode Cups.
There are actually a few ways to defend against POW Block in Mario Kart Wii:
1. In automatic mode when using the wheel, by flicking the remote/wheel up on the third pound (or shaking it wildly after the second). You'll still spin out, but you'll keep your momentum, meaning you can stay in the race! The small blue shockwave that will appear under you will indicate that you've escaped.
2. Driving in manual mode on the 3rd pound, hit the right trigger with the game cube controller ('B' on the Wii Wheel) to hop off the ground. Note that you have to be moving to hop, otherwise your vehicle will try and reverse, because this button has two functions. What this essentially does, its make your character hop off the ground and therefore dodge the power of the POW.
The timing on the first two of these take a little while to master but it is definitely worth it!
3. You can also avoid the hit if you're in midair after launching off a ramp or other big jump. Note Anything that is off the ground when a POW hits will not be effected by it. So half pipe jumps, ramps, cannons, etc. There is not much skill to this, more luck of timing.
Learn these techniques and you will be winning many more races!
Lastly, I would like to recognize and welcome my new co-author Jacon (Jason). He will be helping me add fresh and frequent content on Mario Kart and other Wii titles.