I think that where the weight is carried is very significant. Years of humping a 60 to 120 pound ALICE pack - before the advent of the interceptor or SAPIs - always sucked, no matter how much training preceded it. Patrolling in 85 pounds of gear distributed around my torso was nothing.

I agree that reducing ESAPI weight would be a significant step in reducing overall weight. But I also think that even if we reduced the amount of weight on the torso to zero, things aren't going to change all that much for the guy humping a ruck in the mountains of Afghanistan. Let Soldiers patrol those mountains with just a rucksack and no vest/plates/load-carrying equipment/etc and they're still going to develop the muscular-skeletal problems discussed. Figure out a way for them to patrol with the standard equipment that Soldiers have in Iraq, but no ruck, and I think the problem goes away.

Unfortunately, for the Soldier in Afghanistan, I don't see any way to supply him with water, food, batteries, and ammunition without requiring him to carry it.