Hike a Bike

[madcohn]

I race XC in the 15-16 expert category, and I'm very looking forward for next year, especially because of the Juniors Worlds.
I'm looking constantly for ways to improve my speed on the race course.
I'm improving all the time my technical abilities, I'm doing chin-ups, pushups and sit-ups inorder to be overall stronger. My bike is not very light but it's ligher than 11kg and I'm slowly making it lighter.
I thought yesterday about Hike a Bike sections in some courses...
Is it useful to practice running Hike a Bike sections?
I mean a half-hour/hour that all you do is just run with your bike in hard sections...
Does someone here do it or maybe heard of someone who does?
Do the pros practice this?