Your daily activities shape your overall physical fitness. This is not a difficult concept, but when you explore it fully, the extent to which what you do transforms your body can be shocking. In a recent presentation, Cambridge University anthropologist Dr. Alison Macintosh described how the bones of those living in Central Europe became progressively weaker from around 5,300 B.C., as agriculture became more prominent in the region. In short, the transition from hunting and gathering had dramatic effects on our human bodies, and so, over time, we have become substantially less strong, less fit, and more, well, coach potato-like.

Human bones respond and adapt quickly to change. Bones gain in strength when placed under stress, adding or redistributing fiber based on where the strain caused by physical exertion is greatest. Scientists have demonstrated these adaptations by analyzing the skeletons of modern athletes, whose bones clearly show the intensity (and direction) of repeated strains unique to their sport. Past research has also amply documented the overall changes in human bone strength since the transition from hunting to agriculture, but Macintosh, of Cambridge University’s Department of Archaeology and Anthropology, wanted to gain a better understanding of cultural changes after that.

“I’m interested in how the skeleton adapted to people's specific behaviours during life,” she said in a press release accompanying her presentation at the 83rd Annual Meeting of the American Association of Physical Anthropologists. Even more, she wanted to use bone analysis to help her reconstruct how technological innovations and an increasing complex society (resulting from the advent of farming) created functional adaptations in our human bodies.

To explore this theme, Macintosh began a project in which she laser-scanned skeletons found in cemeteries across Central Europe. Overall, she covered a period of 6,150 years, going back to skeletons from 5,300 B.C. and moving through time to skeletons from about 850 A.D. Her technique included the use of a portable 3D laser surface scanner and she concentrated on the bones in the lower legs — the femora and tibiae, to be precise. What did she discover?

Over time, male tibiae became less rigid, while the bones of both males and females indicated a general drop in mobility. In effect, her skeleton studies showed how people began to carry out a greater variety of activities, many of which were less physically demanding than in the earliest period. Most importantly, Macintosh discovered pronounced gender differences.

“My results suggest that, following the transition to agriculture in Central Europe, males were more affected than females by cultural and technological changes,” she said. “As people began to specialise in tasks other than just farming and food production, such as metalworking, fewer people were regularly doing tasks that were very strenuous on their legs." Ultimately, skeletons show that a body more suited to sitting than laboring did not evolve overnight. Instead, this decline in fitness has been a steady march (crawl?) since the advent of agriculture.