Researchers from ETH Zurich and the University of Zurich deciphered the cellular mechanisms through which tendons can adapt to mechanical stresses. People who carry a certain variant of a gene that is key to this mechanism show improved jumping performance.
At the core of the newly discovered mechanism is a molecular force sensor in the tendon cells consisting of an ion channel protein. This sensor detects when the collagen fibres, that make up the tendons, shift against each other lengthwise. If such a strong shear movement occurs, the sensor allows calcium ions to flow into the tendon cells. This promotes the production of certain enzymes that link the collagen fibres together. As a result, the tendons lose elasticity and become stiffer and stronger.