The full quote/excerpt
Paper after paper, study after study, have shown that chairs give us back problems because they shorten our hip flexors, give us weak backs, of course it makes us sedentary. We take years off our lives probably by sitting in chairs, but we like them because they’re comfortable. You go to an African village, you find me a chair with a back. That’s a rare thing out there.
This item is about:
“Foot strike patterns and collision forces in habitually barefoot versus shod runners,” Lieberman et al, Nature, 2010.
One article on PainScience.com cites this item as a source: