Tendon pain from excessive use is a very common issue in sports activity. It happens if the cumulative load on the tendon is higher than what the tendon can take. There is two parts to this: the first will be the collective load which means simply how much exercise is carried out and how frequently this is done. It is crucial that the tendon has time to get accustomed to those loads or the collective load can exceed that. Which is the second aspect, just how adapted the tendon would be to those loads. Understanding these concepts is extremely important in being familiar with and managing tendonitis.
As an example, peroneal tendonitis which is an overuse injury that occurs on the outside of the ankle joint. The cumulative load in this tendon is increased when exercise amounts are too high or increased too quickly and not sufficient time is given for the tendon to adjust to those higher loads. The cumulative load can also be increased by the biomechanics of the feet. For instance, if the supination resistance of the foot is reduced then the peroneal muscles on the outside of the leg will likely need to work harder. That will put an increased force on the peroneal tendons after which put together with training errors that load could very well go beyond what the tendon can take and it develops tendonitis.
Based upon these principles, peroneal tendonitis is managed by reduction of that collective load. That can mean training amounts and frequency needs to be decreased somewhat to allow the tendon to adapt to the loads. The load in this disorder can also be reduced with foot orthotics that evert the foot, which means the peroneal muscles does not need to work so hard. Next the tendon should be given an opportunity to adapt to the loads. This means that training volume and frequency ought to be slowing increased, with plenty of rest between training loads to give the tendon to adjust to those loads.