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Hillam et al. Skull and leg bones experience wide variations in physiological strain



DOI:10.1038/bonekey.2016.10

This interesting study in one young adult male investigated the level of bone strain induced by exercise and activity in the cranial bones and the tibia.

Hillam et al. implanted small strain gauges within the parietal bones and tibia of a 29-year old healthy volunteer. The strain gauges provided accurate readings as the subject was asked to perform a range of different activities, including eating a banana, biting onto a dental occlusal force meter, pulling faces, walking, performing squats with a 25 kg weight, jumping from 0.45 and 1.3 m, and heading a weighted exercise ball.

As expected, the strains recorded on the two different bones varied markedly. The strain on the tibia was greater than 0.2% during the most vigorous jumping activities. In the skull bones, the maximum parietal strains recorded were 0.0192%, while the subject was heading the exercise ball. Other activities such as eating, biting and grimacing resulted in much lower rates of strain change; these rarely exceeded 0.01% in the parietal bones and were five-fold lower than the rates measured in the tibia.

Editor’s comment: Bone peak strains and strain rates in the tibia were found to be substantially higher than in the cranium of a young male subject performing a broad spectrum of physical activities. Although this is an n=1 study, it makes a rather convincing argument that the set points of the mechanotransduction algorithm involved in bone remodeling are site-specific and dominated by genetic factors.


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