【黃新傑】評論

The relationship between bone remodelling and mechanical loading is usually assumed to follow the so-called Mechanostat Theory4. It states that bone mass is reduced below a lower threshold of mechanical tissue stimulus and increased above an upper threshold leading to a range where no net change occurs, called a ‘lazy zone’ or a ‘dead zone’5,6,7,8,9,10. Many studies were conducted to figure out the response of bone to mechanical loading and thus to support the Mechanostat Theory. It was generally found that bone mass decreased in animals where hind limb bones were immobilized11,12 or in participants of long-term bed rest studies13 and astronauts14,15. On the other hand, bone mass increased when increased loading was applied to bone in vivo as shown in animal experiments, for example, in the turkey ulna16, mouse tibia17 and mouse caudal vertebra18. Such an increased bone mass was also found in human,https://www.nature.com/articles/ncomms5855