Scientific study of soldier loads has been conducted within this decade by folks at Natick Labs/ Soldier Systems Center. Those interested might try to gain contact with OFIG at Natick, part of the Army's RD&E Command under Army Materiel Command. I suspect the results, part of which I know was based on field research with troops on the ground in AF, are probably much better than anything that SLAM anecdotally recounts. I have no better POC information than this link.