Tendons

The extensive collagen network of your muscle comes together towards the end of a muscle's belly, binding together to form a thick highly regularly arranged cord of collagen fibres, called tendon. Tendons transmit the forces generated by muscle to bone, to either brace or move your bones. In a healthy state, tendons are extremely strong structures.

Reflecting the accumulation of high forces generated by muscle further upstream, your tendons have an extremely high tensile strength (the strength to resist being pulled apart). The tensile strength of a tendon is related to its thickness and collagen quality and its arrangement. A tendon with a cross-sectional area of one square centimetre is capable of resisting up to one tonne of force. The strongest tendon in the body, the Achilles tendon (the thick tendon at the back of your heel), can withstand a loading of around 12.5 times the body weight when running flat out.

As a tendon approaches your bone it becomes increasingly denser and harder before imperceptivity blending into your bone. Because of the forces concentrated at them, tendons tend to run into a lot of trouble. Tendinopathy is one of the most common sources of acute and chronic pain affecting the general population of all ages as well as the sporting elite. In fact, it has been reported to be responsible for around 50% of all workplace maladies and sports injuries.