jet, <br> I'm not implying having all the weight at the top. I'm thinking along the lines of 2/3 in the upper half, and 1/3 below. I wear my shoulder straps loose, so the upper part of the rucksack doesn't touch my back. This gives me more ventilation, and I wear a viscose towel around my lumber region to absorb the sweat. This also gives better support to my waist. I can carry 15 kgs easily enough this way.