Tendon injury from too much use is a very common problem in sports activity. It happens when the cumulative load on the tendon surpasses what the tendon can take. There is two parts to this: the first one is the cumulative load and that means simply how much exercise is carried out and just how often it is done. It is crucial that the tendon is given time to get used to those loads or the cumulative load could go beyond that. That is the second part, just how adapted the tendon is to those loads. Understanding these concepts is important in understanding and dealing with tendonitis.
As an example, peroneal tendonitis that is an overuse injury occurring on the outside of the ankle joint. The cumulative load in this tendon is greater when physical activity levels are too high or increased too quickly and not enough time is provided for the tendon to adjust to those high loads. The cumulative load is also increased by the biomechanics of the feet. As an example, if the supination resistance of the foot is lower then the peroneal muscles on the outside of the leg will be required to work harder. That may put an increased force on the peroneal tendons after which in addition to training errors that load could possibly go beyond what the tendon can take and it develops tendonitis.
Based upon these principles, peroneal tendonitis is managed by reducing that collective load. That can mean exercising volumes and frequency ought to be reduced somewhat to allow the tendon to adjust to the loads. The load in this condition will also be reduced with foot orthoses that evert the foot, which means the peroneal muscles will not need to work so hard. Next the tendon must be given a chance to get used to the loads. This means that training quantity and frequency needs to be slowing increased, with lots of rest between training loads to get the tendon to adjust to those loads.