After comparing bone changes in people living in Europe over the past 33,000 years, the researchers found that the strength of both leg bones continued to decline from the Middle Stone Age 10,000 years ago to the Roman Empire 2,000 years ago, but the strength of the upper arm bone, which was not related to running, remained stable. It was during this period that agriculture began to rise and human beings gradually changed to a settled way of life. The rise of agriculture has led to lighter bones in modern humans, but the strength of the two later leg bones has barely changed. The researchers concluded that the effects of mechanization and urbanization on bone strength were not significant.
The most likely hypothesis for the researchers' conclusion is that from 33,000 years ago to 10,000 years ago, the human way of life has not changed significantly.