Pummeling grains for up to five hours a day gave prehistoric women the kind of muscular arms a girl only dreams of today. That's according to researchers at Cambridge University, who used CT scans to compare the upper arm and shinbones of 83 modern women with those of 94 women who lived in Europe 7,400 to 1,200 years ago, during the Neolithic period, Bronze Age, and Iron Age. The research is now highlighting a hidden history of "rigorous" but "underestimated" labor performed by women over thousands of years, researcher Alison Macintosh tells the Guardian. According to her study in Science Advances, Neolithic women had similar leg bone strength as modern women, but their arm bones were 30% stronger than those of modern non-athletic women and 11% to 16% stronger than those of Cambridge's champion female rowers.
It's no wonder why: Ancient women farmed before the invention of the plow. Their duties likely included planting and harvesting crops, grinding grains into flour, making pottery, tending livestock, "processing milk and meat, and converting hides and wool into textiles,'' Macintosh says, per the BBC, explaining in a release that bones evolve over time "to accommodate repeated strain." Strength for women eventually declined, likely as new technologies were introduced. During the Bronze Age, women's arm bones were 9% to 13% stronger than those of the rowers. By the Middle Ages, a woman's upper arm bone was about as strong as that of a modern woman, says Macintosh, whose previous research identified a similar trend in the leg bones of men over time. (See how female brains differ from male brains.)