How to carry a MTB on one's backpack? Sometimes I want to ascend a steep (say, 50%) slope, where is impossible to ride and awkward to push/pull the bike.

I tried various ways of carrying the bike:


Lifting it just 10 cm above the ground - good for very short sections
Lifting it with one hand to shoulder height - good for short sections; the arm gets tired quicky
Holding it above my neck with two hands; the arms get numb quickly
Putting it on my backpack; the back starts to ache at random places, as if warped


I imagine the last idea, with resting the bike on the backpack, is the only usable one for long sections (say, 30-60 minutes walking). Am I right?

Which way can I secure my bike on my backpack, so the back ache (and supposedly damage) is minimized?



Update: I had a half-full 35-litre backpack at the day I had this problem. I am willing to fill my pack with light bulky stuff if needed, but I don't want a bigger pack: 35 L seems enough for maximal journeys I want to do; any bigger and it starts to be annoying.
My friends and I have hiked a lot while carrying our bikes. What I've found that works best is:


go to the non drive side of the bike
drop the non drive side pedal down
left hand on the left fork lower
right hand on the non drive side crank arm
lift whole bike and place bottom tube behind your neck


This works because:


bike is central on top of you and you can easily remove one or both hands whenever necessary
you don't get dirty because the drive side is away from you


To lift the bike, your hands should go to the two red spots:



Also see How to shoulder a bike?