| Tendon Stiffness, Recoil and Accelerations |

Tendon ‘stiffness’ has nothing to do with our understanding of the word when we talk about flexibility, or range of motion. In this sense ‘stiffness’ is a mechanical property describing the relationship between the force applied to the muscle-tendon complex (MTC) and the change in the length of the unit. So if a greater degree of force is needed to produce a given amount of stretch, we can say the muscle-tendon complex (MTC) is stiffer. Correspondingly, the exertion of less force to produce the stretch means the muscle-tendon complex (MTC) is more ‘compliant’

In sport, stiffness is not necessarily a bad thing. Tasks which require high accelerations, require high muscular contractions and high tendon recoils. A stiff tendon provides this type of recoil needed to transfer energy from muscle to bone. MTCs involved in short ranges of movement, such as the ankle and knee in running, will benefit from being stiff, while MTCs that are involved in large ranges of movement, such as many athletic hip or shoulder movements, will benefit from being compliant (longer and thinner).

In industry, we have discussed control of the ‘athletes’ health is much more difficult than in sport and high acceleration tasks placing more overall stress on the muscles attaching tendons. Because of this, we need to continue altering the work environment so that tasks do not require high accelerations and thus high muscle contraction to complete the tasks at hand. If you are in need of assistance designing or re-designing, determining the workplace risk or need help implementing administrative controls to eliminate or mitigate higher accelerative tasks, please contact us and let us know your needs.