女生小视频

CYCLING gives you healthier bones鈥攂ut only if you have a bumpy ride.
Janet Shaw at the University of Utah, Salt Lake City, and her team measured the
bone density of two groups of elite male cyclists: road racers and mountain
bikers. They found that the off-roaders had denser bones (Bone, vol 30,
p 281) that would be less prone to breaks and fractures. The road racers鈥� bones
were no different to a control group of men who did not cycle competitively.
鈥淭he skeleton responds to things out of the ordinary,鈥� says Shaw. So the jolts
and scrapes suffered by the cross-country thrill-seekers probably explain the
difference.