Farming is hard work, and prehistoric women in Central Europe—who tilled and harvested fields, ground grain, and hauled crops without help from modern equipment—likely had the muscles to prove it, according to a new study spotted by Discover.

Published in the journal Science Advances, the study compared the arm and leg bones of modern female athletes to those of female farmers from Central Europe during four different eras spanning 5500 years—the Neolithic Era, the Bronze Age, the Iron Age, and the Medieval period. Using laser scans and molds, Cambridge archaeologist Alison Macintosh and a team of scientists were able to examine the bones' shapes and rigidity, as these factors indicate how much muscle they once had around them. They measured these observations against CT scans of female Cambridge University rowers, endurance runners, and soccer players, as well as those of non-athletes.

Not only were the Neolithic women's leg bones comparable in strength to those of the rowers, the arm bones were 11 to 16 percent stronger. (When sedentary students were factored into the mix, this difference in strength was as high as 30 percent.) Strength also ranged among prehistoric women, suggesting that women specialized in specific forms of manual labor.

These findings contradict the theory that prehistoric women performed domestic work instead of manual labor. Around 10,000 years ago, humans began shifting from hunting and gathering to farming. This didn't just change their eating habits—it also changed their bones, as skeletons stretch and twist in response to stresses. Because men were running less, their shinbones became straighter and less stiff. But women's shinbones remained largely the same over the time periods, prompting some scholars to conclude that they performed less strength-intensive tasks. The paper's authors say that theory underestimates women's activity in prehistoric societies.

Plus, Discover points out, studies of prehistoric behavior often compare female skeletons with male ones—an unfair comparison, considering that men's bodies respond differently to strain.

"We felt it was likely a huge oversimplification to say [prehistoric women] were simply not doing that much, or not doing as much as the men, or were largely sedentary," Macintosh told Science.

[h/t Discover]