When soft tissue structures endure ongoing stress and have no time to heal, it results in an overuse injury. According to a recent review, overuse injuries account for 42% in individual sports and 33% in team sports (33%), most commonly affecting the lower limbs.
The most common cause of overuse injury is training errors, specifically involving physical training too much, too soon.
This includes inappropriate training progression in type, intensity, and quantity, such as when shifting to a different exercise or activity too quickly, exercising for too long a period without adequate rest periods, or simply doing too much of one type of exercise. It may also include shifting to a different training environment, such as when running uphill from previously flat track running.
Improper technique including poor form and biomechanics may overload certain soft tissues (e.g. improper golf swing form and technique can injure the back; poor backhand may result in tennis elbow). In the weights room, technique errors are often seen in the bench press and squat techniques.
Exercising or training an already injured and incompletely healed tissue cannot accommodate previously accustomed loads and stresses and may result in aggravation and overuse. Continued athletic participation despite inadequate rehabilitation can also put undue stress on other areas of the limb.
Repetitively working the same joints or muscles without variation in technique increases the risk for overuse injuries. Specializing in one sport without practicing cross-training may also be a causative factor.
Using improperly and inappropriately fitted sports gear and equipment can interfere with proper mechanics and force distribution and may cause sports-related injuries (e.g. inappropriate tennis racket grip size may exert forces on certain muscles and cause lateral epicondylalgia).
Muscular imbalances may cause an abnormal pull to the opposing muscles and associated joint structures. When repetitively used muscles become stronger than the less activated muscles, the former overcompensates for the weaker. When the weaker muscles fail to match the strength and endurance of the stronger muscle, they fatigue more easily, causing the stronger ones to work harder. Over time, these muscles wear down and develop overuse injuries.
Anatomical and biomechanical variations affect the distribution of forces applied to the joint. Malalignment, such as knock-knees, bowlegs, leg lengths discrepancy, and flat feet, also cause overuse injuries. Many people also have weak links due to old injuries, incompletely rehabilitated injuries, or other anatomic factors.
The majority of the overuse injuries in sports, as well as in daily life, affect the lower limbs, specifically due to the enormous amount of load it bears as it supports the weight of the trunk and the upper limb. Generally, the knee, tibia, and thigh are the most affected areas.
Iliotibial Band Friction Syndrome: ITBFS is an inflammatory, non-traumatic overuse injury of the knee affecting predominantly long-distance runners, especially with excessive downhill running, or bicyclists who are not conditioned for longer rides. It is caused by the rubbing of the band against the the lateral femoral epicondyle during knee motion, resulting in pain and inflammation.
Achilles Tendinitis: Chronic pain and inflammation of the Achilles tendon due to repetitive stresses, which is most commonly seen in sports associated with frequent jumping or running, especially in uneven terrain and hill-running.
Patellar Tendinitis: Pain in the patellar tendon caused by patellar degeneration caused by overuse and repetitive overload of the quadriceps tendon. Often termed as “jumper’s knee” as it’s usually seen in sports associated with frequent jumping.
Shin Splints: Also known as the medial tibial stress syndrome, shin splints are periostitis, the inflammation of the periosteum or the band of connective tissue that surrounds the bone.
Plantar Fasciitis: Inflammatory stress syndrome of the plantar fascia or plantar aponeurosis, usually at its medial calcaneal origin. It is believed that this syndrome is related to the stress on the plantar fascia from the weight of an activity combined with weight transfer up onto the toes and leading to MTP joint extension with a “windlass” effect on the plantar fascia.