>>2166625ya bro its pretty well known that you use your shoulder straps to adjust your center of gravity either closer to your body for uphill or further for downhill. that doesn't change the fact that the weight should be mainly, once again, on your iliac crest, regardless of incline or decline: hence the hip belt. Of course you will have some weight allocated to your upper body, that was never in dispute. Nicer more modern packs will have load lifter straps to aid with this adjustment, and to better distribute the load across your shoulders (pic related).
