Post by UKarchaeology on Sept 30, 2015 17:07:25 GMT
* Researchers analysed a sample of 1,842 individuals from across Europe
* Samples dated from the Upper Paleolithic through to the 20th century
* Bones were studied for strength relative to body size and mobility
* Large decline in strength occurred at the start of the Neolithic (7,300 and 4,000 BC) that continued through the Iron/Roman period (2,250 to 1,650 BC)
It is a problem often blamed on our modern lifestyles and reliance on machines, but it seems it was the spread of farming that really caused our bones to weaken.
Scientists have long known that our hunter-gatherer ancestors had stronger and more robust bones than modern-day humans, but have struggled to pinpoint exactly when this change happened.
Now new research studying a sample of bones covering 30,000 years has revealed that the decline in bone strength began with early food production during the Neolithic period.
Professor Ruff analysed a sample of bones taken from 1,842 individuals from across Europe (plotted above) to study changes in skeletal robusticity - bone strength relative to body size - and mobility. These samples covered a period from the Upper Paleolithic through to the 20th century, spanning the past 30,000 years
It then continued for several thousands of years as agriculture intensified.
Agriculture - while still labour intensive - meant people moved around far less than in hunter gatherer societies and also gave greater opportunity for leisure time.
The use of animals by early farmers would also have reduced the strain on their bones.
Most significantly, this proves farming practices in general made us more sedentary as people moved around far less, and this trend began long before the introduction of mechanisation and industrialisation.
Subsequently, the rise of machines - which began in earnest with the industrial revolution - played a smaller role than first thought.
The latest study, Gradual decline in mobility with the adoption of food production in Europe, was published by Professor Christopher Ruff and his colleagues from Johns Hopkins University School of Medicine.
Professor Ruff analysed a sample of 1,842 individuals from across Europe to study changes in skeletal robusticity - bone strength relative to body size - and mobility.
These samples covered a period from the Upper Paleolithic through to the 20th century, spanning the past 30,000 years.
'Increased sedentism during the Holocene has been proposed as a major cause of decreased skeletal robusticity in modern humans,' explained the researchers.
Farming led the ancient Egyptians to flourish around 5,000 years ago (above) but also weakened their bones
The study found a large decline in bending strength of the femur and tibia at the start of the Neolithic (7,300 and 4,000 BC), and continued through the Iron/Roman period (2,250 to 1,650 BC). Declines in the strength of the lower limbs, and strength of the humerus were found to be much smaller and less consistent (shown)
This chart reveals which time period each bone sample originated from. The findings suggest farming practices in general made us more sedentary, and this trend began before the introduction of mechanisation and industrialisation. But, the rise of machines played a smaller role than first thought
'When and why declining mobility occurred has profound implications for reconstructing past population history and health, but it has proven difficult to characterise archaeologically.'
In the recent study, the team evaluated trends in relative strength of the upper and lower limb bones.
They found a large decline in anteroposterior bending strength of the femur and tibia at the beginning of the Neolithic (7,300 and 4,000 BC), and continued through the Iron/Roman period (2,250 to 1,650 BC).
Declines in the bending strength of the lower limb bones, and strength of the humerus were found to be much smaller and less consistent.
'Together these results strongly implicate declining mobility as the specific behavioural factor underlying these changes' continued the team.
'Mobility levels first declined at the onset of food production, but the transition to a more sedentary lifestyle was gradual, extending through later agricultural intensification.
Research from University of Cambridge, covering a period of more than 7,000 years of human evolution, recently revealed modern-day skeletons (pictured bottom) are lighter and more fragile than those belonging to our hunter-gatherer ancestors (pictured top). They studied hip joints on ancient femurs
'This finding only partially supports models that tie increased sedentism to a relatively abrupt Neolithic Demographic Transition in Europe.
'The lack of subsequent change in relative bone strength indicates that increasing mechanisation and urbanisation had only relatively small effects on skeletal robusticity, suggesting that moderate changes in activity level are not sufficient stimuli for bone deposition or resorption.'
The findings are published in the journal PNAS.
Professor Ruff's research follows an earlier study, from the University of Cambridge, which used X-rays and CT scans to study ancient samples of human femur bones, along with femora from other primate species.
In particular, they focused on the inside of the femoral head - the ball at the top of the femur which fits into the pelvis to form the hip joint.
This joint is one of the most load-bearing bone connections in the body.
There are two types of tissue that form bone. The cortical or 'hard' bone shell on the outside, and the trabecular or 'spongy' bone on the inside.
This trabecular bone is a honeycomb-like mesh inside the cortical shell that allows flexibility, but is also vulnerable to fracture.
The bones studied covered four distinct archaeological human populations representing mobile hunter-gatherers from 7,300 years ago, and more recent, sedentary agriculturalists.
All were found in the same area of Illinois, and were therefore likely to be genetically similar.
The trabecular structure was found to be very similar in all populations, but the hunter-gatherers had a much higher amount of actual bone relative to air.
'Trabecular bone has much greater plasticity than other bone, changing shape and direction depending on the loads imposed on it; it can change structure from being pin or rod-like to much thicker, almost plate-like. In the hunter-gatherer bones, everything was thickened,' said lead researcher Dr Colin Shaw.
This thickening is the result of constant loading on the bone from physical activity as hunter-gatherers roamed the landscape, seeking food.
Bone mass was found to be around 20 per cent higher in the foragers - the equivalent to what an average person would lose after three months of weightlessness in space. Pictured is an early Neolithic (approximately 4000 - 5000 BC) 35 to 40-year-old male used to illustrate ancient skeletons
This exertion would result in minor damage that caused the bone mesh to grow back stronger and thicker throughout life - building to a 'peak point' of bone strength, which counter-balanced the deterioration of bones with age.
Bone mass was around 20 per cent higher in the foragers - the equivalent to what an average person would lose after three months of weightlessness in space.
And after ruling out diet differences and changes in body size as possible causes, researchers concluded a drop in physical activity are the root cause of degradation in human bone strength across millennia.
They believe the findings support the idea that exercise, rather than diet, is the key to preventing heightened fracture risk and conditions, such as osteoporosis, in later life.
The next step for Dr Shaw's research team will be to look at how different types of loading and mobility shape bodies and bones by cross-referencing archaeological records with testing on modern ultra-marathon runners, and athletes (Mo Farah pictured left). An ancient farmer is illustrated right
(pics & source at: www.dailymail.co.uk/sciencetech/article-3086398/Farming-Neolithic-food-production-caused-legs-weak.html )
* Samples dated from the Upper Paleolithic through to the 20th century
* Bones were studied for strength relative to body size and mobility
* Large decline in strength occurred at the start of the Neolithic (7,300 and 4,000 BC) that continued through the Iron/Roman period (2,250 to 1,650 BC)
It is a problem often blamed on our modern lifestyles and reliance on machines, but it seems it was the spread of farming that really caused our bones to weaken.
Scientists have long known that our hunter-gatherer ancestors had stronger and more robust bones than modern-day humans, but have struggled to pinpoint exactly when this change happened.
Now new research studying a sample of bones covering 30,000 years has revealed that the decline in bone strength began with early food production during the Neolithic period.
Professor Ruff analysed a sample of bones taken from 1,842 individuals from across Europe (plotted above) to study changes in skeletal robusticity - bone strength relative to body size - and mobility. These samples covered a period from the Upper Paleolithic through to the 20th century, spanning the past 30,000 years
It then continued for several thousands of years as agriculture intensified.
Agriculture - while still labour intensive - meant people moved around far less than in hunter gatherer societies and also gave greater opportunity for leisure time.
The use of animals by early farmers would also have reduced the strain on their bones.
Most significantly, this proves farming practices in general made us more sedentary as people moved around far less, and this trend began long before the introduction of mechanisation and industrialisation.
Subsequently, the rise of machines - which began in earnest with the industrial revolution - played a smaller role than first thought.
The latest study, Gradual decline in mobility with the adoption of food production in Europe, was published by Professor Christopher Ruff and his colleagues from Johns Hopkins University School of Medicine.
Professor Ruff analysed a sample of 1,842 individuals from across Europe to study changes in skeletal robusticity - bone strength relative to body size - and mobility.
These samples covered a period from the Upper Paleolithic through to the 20th century, spanning the past 30,000 years.
'Increased sedentism during the Holocene has been proposed as a major cause of decreased skeletal robusticity in modern humans,' explained the researchers.
Farming led the ancient Egyptians to flourish around 5,000 years ago (above) but also weakened their bones
The study found a large decline in bending strength of the femur and tibia at the start of the Neolithic (7,300 and 4,000 BC), and continued through the Iron/Roman period (2,250 to 1,650 BC). Declines in the strength of the lower limbs, and strength of the humerus were found to be much smaller and less consistent (shown)
This chart reveals which time period each bone sample originated from. The findings suggest farming practices in general made us more sedentary, and this trend began before the introduction of mechanisation and industrialisation. But, the rise of machines played a smaller role than first thought
'When and why declining mobility occurred has profound implications for reconstructing past population history and health, but it has proven difficult to characterise archaeologically.'
In the recent study, the team evaluated trends in relative strength of the upper and lower limb bones.
They found a large decline in anteroposterior bending strength of the femur and tibia at the beginning of the Neolithic (7,300 and 4,000 BC), and continued through the Iron/Roman period (2,250 to 1,650 BC).
Declines in the bending strength of the lower limb bones, and strength of the humerus were found to be much smaller and less consistent.
'Together these results strongly implicate declining mobility as the specific behavioural factor underlying these changes' continued the team.
'Mobility levels first declined at the onset of food production, but the transition to a more sedentary lifestyle was gradual, extending through later agricultural intensification.
Research from University of Cambridge, covering a period of more than 7,000 years of human evolution, recently revealed modern-day skeletons (pictured bottom) are lighter and more fragile than those belonging to our hunter-gatherer ancestors (pictured top). They studied hip joints on ancient femurs
'This finding only partially supports models that tie increased sedentism to a relatively abrupt Neolithic Demographic Transition in Europe.
'The lack of subsequent change in relative bone strength indicates that increasing mechanisation and urbanisation had only relatively small effects on skeletal robusticity, suggesting that moderate changes in activity level are not sufficient stimuli for bone deposition or resorption.'
An earlier study by Cambridge University found that mankind is shrinking in size significantly.
Experts say humans are past their peak and that modern-day people are 10 per cent smaller and shorter than their hunter-gatherer ancestors.
And if that's not depressing enough, our brains are also smaller.
The findings reverse perceived wisdom that humans have grown taller and larger, a belief which has grown from data on more recent physical development.
The decline, said scientists, has happened over the past 10,000 years. They blame agriculture, with restricted diets and urbanisation compromising health and leading to the spread of disease.
The theory has emerged from studies of fossilised human remains found in Africa, Europe and Asia.
The earliest, from Ethiopia, date back 200,000 years, and were larger and 'more robust' than their modern-day counterparts, said Dr Marta Lahr, an expert in human evolution.
Experts say humans are past their peak and that modern-day people are 10 per cent smaller and shorter than their hunter-gatherer ancestors.
And if that's not depressing enough, our brains are also smaller.
The findings reverse perceived wisdom that humans have grown taller and larger, a belief which has grown from data on more recent physical development.
The decline, said scientists, has happened over the past 10,000 years. They blame agriculture, with restricted diets and urbanisation compromising health and leading to the spread of disease.
The theory has emerged from studies of fossilised human remains found in Africa, Europe and Asia.
The earliest, from Ethiopia, date back 200,000 years, and were larger and 'more robust' than their modern-day counterparts, said Dr Marta Lahr, an expert in human evolution.
The findings are published in the journal PNAS.
Professor Ruff's research follows an earlier study, from the University of Cambridge, which used X-rays and CT scans to study ancient samples of human femur bones, along with femora from other primate species.
In particular, they focused on the inside of the femoral head - the ball at the top of the femur which fits into the pelvis to form the hip joint.
This joint is one of the most load-bearing bone connections in the body.
There are two types of tissue that form bone. The cortical or 'hard' bone shell on the outside, and the trabecular or 'spongy' bone on the inside.
This trabecular bone is a honeycomb-like mesh inside the cortical shell that allows flexibility, but is also vulnerable to fracture.
The bones studied covered four distinct archaeological human populations representing mobile hunter-gatherers from 7,300 years ago, and more recent, sedentary agriculturalists.
All were found in the same area of Illinois, and were therefore likely to be genetically similar.
The trabecular structure was found to be very similar in all populations, but the hunter-gatherers had a much higher amount of actual bone relative to air.
'Trabecular bone has much greater plasticity than other bone, changing shape and direction depending on the loads imposed on it; it can change structure from being pin or rod-like to much thicker, almost plate-like. In the hunter-gatherer bones, everything was thickened,' said lead researcher Dr Colin Shaw.
This thickening is the result of constant loading on the bone from physical activity as hunter-gatherers roamed the landscape, seeking food.
The bones studied covered four distinct archaeological human populations. The trabecular, mesh-like structure was found to be similar in all populations, but hunter-gatherers (left) from 7,000 years ago had a much higher amount of actual bone relative to air than agriculturalists (right) just 1,000 years later
Bone mass was found to be around 20 per cent higher in the foragers - the equivalent to what an average person would lose after three months of weightlessness in space. Pictured is an early Neolithic (approximately 4000 - 5000 BC) 35 to 40-year-old male used to illustrate ancient skeletons
This exertion would result in minor damage that caused the bone mesh to grow back stronger and thicker throughout life - building to a 'peak point' of bone strength, which counter-balanced the deterioration of bones with age.
Bone mass was around 20 per cent higher in the foragers - the equivalent to what an average person would lose after three months of weightlessness in space.
And after ruling out diet differences and changes in body size as possible causes, researchers concluded a drop in physical activity are the root cause of degradation in human bone strength across millennia.
They believe the findings support the idea that exercise, rather than diet, is the key to preventing heightened fracture risk and conditions, such as osteoporosis, in later life.
The next step for Dr Shaw's research team will be to look at how different types of loading and mobility shape bodies and bones by cross-referencing archaeological records with testing on modern ultra-marathon runners, and athletes (Mo Farah pictured left). An ancient farmer is illustrated right
(pics & source at: www.dailymail.co.uk/sciencetech/article-3086398/Farming-Neolithic-food-production-caused-legs-weak.html )