Injuring Tendons as We Age
The risk of tendon injuries increases with age but scientists have never fully understood why. Now research led by Queen Mary University of London has discovered a specific mechanism that is crucial to effective tendon function. The finding could reveal why older people are more prone to tendon injury.
A release from the university notes that tendons, such as the Achilles, connect muscle to bone and are “loaded” repeatedly during movement. When exposed to particularly high loads, injury can result. Because tendon injury is common in horses as well as humans, the team — working together with scientists from the University of Liverpool, University College London and the University of East Anglia –used tendons from deceased horses to understand injury risk and demonstrate the loading mechanism in action.
The researchers found that fascicles – the subunit that makes up tendons – are coiled like a spring, or curved helix. They have shown that the helix structure enables tendons to stretch and recover, with results suggesting that damage to the helix stops the tendon working properly.
The release quotes co-author Dr Hazel Screen as saying, "The helical shape of the fascicles seems to be critical in maintaining tendon elasticity. Repetitive loading causes the fascicles to unwind and be less effective, triggering them to become damaged or leading to injury."
The team also showed how aging affects the helix. Co-author Dr Chavaunne Thorpe said: "The findings suggest that the helix structure is altered with age resulting in a decreased ability to withstand further loading and so making aged tendons more prone to injury."