Tendon injury from excessive use is a very common issue in sports activity. It occurs when the cumulative strain on the tendon surpasses what the tendon can take. There is two parts to this: the first is the collective load which means the amount of exercise is taken on and just how frequently this is done. It is crucial that the tendon has time to get accustomed to those loads or the collective load might go beyond that. That's the second part, just how adapted the tendon would be to those loads. Being familiar with these principles is really important in understanding and treating tendonitis.
One example is, peroneal tendonitis that is an overuse injury that occurs on the outside of the ankle joint. The cumulative load in this tendon is elevated when activity amounts are too high or increased too quickly and not sufficient time is provided for the tendon to adjust to those high loads. The cumulative load is also increased by the biomechanics of the foot. 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 can place an increased stress on the peroneal tendons after which put together with training errors that load will probably exceed what the tendon can take and it develops tendonitis.
Based upon these principles, peroneal tendonitis is managed by lessening that collective load. That can mean training volumes and frequency must be decreased somewhat to allow the tendon to adjust to the loads. The load in this condition can also be reduced with foot orthoses that evert the foot, which means the peroneal muscles does not need to work so hard. Then the tendon must be given a chance to adapt to the loads. This implies that exercising quantity and frequency needs to be slowing increased, with plenty of rest between training loads to get the tendon to adjust to those loads.