davidtaylforth if your hitting a lip / jump you dont need to lift up.... gravity does it for you when you hit the jump. Like I said watch some films of the pro's! not pulling up was the biggest thing I learnt, it lets you focus on the trail and your body position............
Well I guess it depends on your style etc. and yes you can just clear jumps by relaxing and floating over but this isnt as much fun.
If you want to jump properly then you need to pump the bottom of the take off and pull up, generally the harder you pull the higher you go. This is surely correct (unless i ride like an oddun') as I rode my BMX at the trails only about 2 hours ago, and I definitely pulled up on the take off.
If you watch some films of the pros you'll see they do pull up. How do you think Chase Hawk boosts so high? By riding into the jump and letting gravity do it for him?