Tendon injury from overuse is a very common issue in sport. It occurs if the load that the tendon is exposed to exceeds what the tendon can take. There is two parts to this. The first will be the cumulative load and that means simply how much exercise is done and just how often this is done. It is essential that the tendon is given time to get accustomed to those loads or the collective load will go beyond that. That is the second part, just how adapted the tendon would be to those loads. Understanding these concepts is really important in being familiar with and treating tendonitis.
One example is, peroneal tendonitis which is an excessive use injury that occurs on the outside of the ankle joint. The collective load in this tendon is greater when activity levels are too high or increased too quickly and not enough time is given for the tendon to adapt to those high loads. The cumulative load is also increased by the biomechanics of the foot. For 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 place an increased stress on the peroneal tendons after which along with training errors that load may well exceed what the tendon can take and it develops tendonitis.
Based upon these principles, peroneal tendonitis is managed by reduction of that collective load. That will mean training volumes and frequency should be decreased somewhat to permit the tendon to adapt to the loads. The stress in this disorder can also be decreased with foot orthotics that evert the foot, which means the peroneal muscles does not need to work so hard. Next the tendon ought to be given an opportunity to adapt to the loads. This means that exercising volume and frequency ought to be slowing increased, with lots of rest between training loads to give the tendon to adapt to those loads.