People with bone wasting conditions could do with a good shaking, according to US scientists. They found that sheep that spent time standing on a vibrating plate developed much stronger bones than those that did not.
“The animals would line up to go on this thing,” says Clinton Rubin at the State University of New York. “And if you used your imagination, they looked like they were smiling.” Scientists previously thought that bones were only strengthened when subjected to the kinds of strains produced by activities like walking or running. But Rubin says that even when a person stands still, the bones in their legs are subjected to small cycling strains – due to muscle activity – that could have an effect on bone cells.
To check, Rubin rounded up a herd of sheep and set about shaking them. Each sheep stood on a plate which vibrated imperceptibly – producing tiny strains in the sheeps’ limbs at 30 cycles a second. After a year’s treatment of 20 minutes, five days a week, Rubin measured how much bone the sheep had gained in their legs. “We saw that this produced tonnes of bone – a 35 per cent increase.”
Rubin says that the technique might work for people with osteoporosis and Peter Augat, at the University of Ulm, Germany, says the idea of treating people who can not walk easily is appealing – if it works.
“We tried to repeat the study in people and were not able to reproduce these results – sheep may be more susceptible to these strains,” he says. Augat’s study measured women after subjecting them to similar strains twice a week for six months.
Rubin adds that the technique could even be adapted to help prevent astronauts losing bone mass while in space. “They get around two percent bone loss per month – which means they are losing bone about 12 times faster than people with osteoporosis on Earth,” says Rubin.
Allen Goodship at the University of London has tested a similar idea on the Mir space station. The cosmonauts exercised on a resistive step machine, but one footplate was adapted to produced additional high frequency vibrations in the bones; the other leg was the control.
In one cosmonaut, the bone densities of the untreated heel and shin bones fell by up to seven per cent during the flight but the treated leg lost no bone. However, the beneficial effect did not reach as high as the hip.
Journal reference: Nature (vol 412, p 603)