The researchers who conducted the study believe that this change occurred when the humans discovered and engaged in agriculture, thus reducing their mobility.
The recent findings help the scientists better understand how these changes contributed to the modern human’s susceptibility to bone illnesses like osteoporosis. Also, the experts want to understand why is it that humans who stress their bones by exercising have stronger bones and are richer in minerals like calcium.
Professor Christopher Ruff, an expert in functional anatomy and evolution at the Johns Hopkins University School of Medicine and one of the researchers who conducted the new study, explained that there is plenty of evidence that ancient humans’ bones were a lot stronger than modern ones’.
Also, it is known that exercise helps prevent bone loss.
However, professor Ruff said that it’s not clear whether the bones started to lose their strength over the past 30,000 years or this shift was a result of the discovery modern activities like agriculture, changes in diet, domestication of horse, urbanization or any other lifestyle changes that helped the modern humans transform into what they are today.
The researchers analyzed numerous arm and leg bones from human ancestors that lived throughout the 30,000 years time span.
The studies revealed that the bones of the European humans started to grow weaker gradually as they discovered agriculture and adopted it. This made the humans settle down and lead a more sedentary lifestyle than what they had before.
The analysis also showed that factors like moving into cities did not have an impact on the humans’ bones.
In order to come to these conclusions, the scientists took molds of bones that belonged to humans living in Europe in the last 33,000 years.
The researchers also used a portable X-ray technology to can the bone samples and analyze the major bones of the legs and arms.
Professor Ruff explained that his team compared the lower limbs with the upper ones to determine whether the changes in bone strength occurred due to mobility or were caused by other factors like nutrition.
According to the analysis, the bones started to lose strength sometime between the Mesolithic period- approximately 10,000 years ago- and the age of the Roman Empire -2,500 years ago.
The researchers published their findings in the journal Proceedings of the National Academy of Sciences.
Image Source: livescience