Tendon pain from excessive use is a common injury in sports activity. It happens when the cumulative strain on the tendon is higher than what the tendon can take. There is two parts to this: the first one is the cumulative load which means the amount of exercise is taken on and how often it is done. It is essential that the tendon has time to get accustomed to those loads or the cumulative load might go beyond that. That is the second aspect, just how adapted the tendon is to those loads. Understanding these principles is crucial in being familiar with and treating tendonitis.
One example is, peroneal tendonitis which is an overuse injury occurring on the outside of the ankle joint. The cumulative load in this tendon is increased when exercise levels are too high or increased too quickly and not enough time is given for the tendon to adapt to those higher loads. The cumulative load is also increased by the biomechanics of the feet. For example, if the supination resistance of the foot is low then the peroneal muscles on the outside of the lower limb will need to work harder. That will place an increased load on the peroneal tendons and then along with training errors that load will probably exceed what the tendon can take and it develops tendonitis.
Based upon these concepts, peroneal tendonitis is treated by lessening that cumulative load. That could mean exercising volumes and frequency need to be decreased somewhat to allow the tendon to adapt to the loads. The strain in this condition may also be decreased with foot orthoses that evert the foot, which means the peroneal muscles does not need to work so hard. Then the tendon should be given an opportunity to adapt to the loads. This implies that exercising amount and frequency ought to be slowing increased, with lots of rest between training loads to get the tendon to adapt to those loads.