I read about this in the journal Nature a couple of days ago.
http://www.nature.com/nature/journal/v444/n7122/abs/4441023a.html
Seems to make sense and it means that with this new design 60 lbs will only require the energy cost of carrying a 48 pound pack. It is also discussed on the Nature podcast. The inventor, who is at UPenn, thought the design might show up on the market in 1-2 years.
http://www.nature.com/nature/journal/v444/n7122/abs/4441023a.html
Seems to make sense and it means that with this new design 60 lbs will only require the energy cost of carrying a 48 pound pack. It is also discussed on the Nature podcast. The inventor, who is at UPenn, thought the design might show up on the market in 1-2 years.