Tendon injury from excessive use is a common problem in sports activity. It occurs in the event the cumulative strain on the tendon is greater than what the tendon can take. There is two parts to this: the first is the cumulative load which means the amount of activity is undertaken and how often this is done. It is crucial that the tendon is given time to adjust to those loads or the cumulative load can go beyond that. That's the second aspect, just how adapted the tendon would be to those loads. Understanding these principles is really important in understanding and dealing with tendonitis.
One example is, peroneal tendonitis that is an overuse injury that occurs on the outside of the ankle joint. The collective load in this tendon is greater when activity amounts 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 low then the peroneal muscles on the outside of the lower limb will likely need to work harder. That may put an increased strain on the peroneal tendons after which coupled with training errors that load may very well exceed what the tendon can take and it develops tendonitis.
Based upon these concepts, peroneal tendonitis is managed by reduction of that collective load. That could mean exercising amounts and frequency have to be reduced somewhat to allow the tendon to adjust to the loads. The stress in this disorder 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 really needs to be given a chance to get used to the loads. This means that training amount and frequency has to be slowing increased, with lots of rest between training loads to get the tendon to adjust to those loads.