Overuse Injuries in the Young Athlete – An Update

During the past two decades, involvement in youth sports has increased dramatically. The positive health and psychological benefits of sports participation include fitness, agility, strength, team play, bolstered self-esteem and confidence.¹ Unfortunately, the inherent rewards of sports are often coupled with deleterious adversities, which include overtraining, burnout and overuse injuries in child and adolescent athletes. The rise in youth participation in organised athletics over this time period has generated a foreseeable increase in both acute (macrotrauma) and repetitive microtrauma, or overuse injuries, the reasons for which remain multifactorial.

Rather than provide an extensive overview of the common overuse injuries in the child and adolescent athlete, the purpose of this review is to outline the causative factors and strategies for injury prevention to assist clinicians in guiding young athletes, their parents and coaches through the adolescent growth spurt with its accompanying pitfalls. While most sports-related injuries in youth are minor and self-limiting, the young athlete’s skeletal immaturity places him or her at significant risk for impairment of growth and permanent damage.

Overuse Injuries – Definition, Classification and Cause
Overuse injuries, by definition, occur when repetitive stress is applied to a muscle, tendon or bone, ultimately resulting in microtraumatic damage when adequate time to heal or repair has not been allotted. Overuse injuries can be classified according to four progressive stages:

• pain in the affected area following physical activity;
• pain during activity that does not restrict performance;
• pain during activity that restricts performance; and
• chronic, persistent pain even at rest.

It has been estimated that nearly 50 % of injuries presenting to paediatric sports medicine practices are related to overuse. ² Causative factors for overuse injuries can be categorised into intrinsic and extrinsic factors.³ Intrinsic factors are inherent to the athlete themselves and include anatomy, growth and development, nutrition and pre-existing conditions. Extrinsic factors include training errors, environmental and equipment factors.⁴

Intrinsic Factors
Anatomical
Several ‘physiological’ malalignments of the lower extremities can predispose young athletes to overuse injuries. These include anteversion of the pelvis, medial femoral anteversion, internal or external tibial torsion and foot overpronation/-supination. Individually or collectively these conditions can contribute to tracking abnormalities of the patella, stress injuries and other chronic conditions of the hip, knee and ankle for young athletes participating in sports that are particularly demanding of the lower extremities, such as running, soccer and lacrosse. Additionally, leg length discrepancies, both structural and functional, can contribute to chronic back and lower extremity pain. When undetected, such discrepancies can lead to compensatory changes in gait and posture that may contribute to myriad overuse injuries associated with lower extremity malalignment. ⁴

Growth and Development
With the onset of the adolescent growth spurt comes a multitude of predispositions for overuse injuries. Long bone growth advances rapidly, leaving inadequate time for compensatory elongation and flexibility of the accompanying muscle tendon units. Consequently, tightness of the quadriceps, hip flexors, hamstrings and gastrocnemius–soleus complex often afflict the peripubescent athlete. Clinical manifestations can include acute avulsion fractures of the pelvis and overuse physeal injuries. The overuse physeal injuries can be further categorised as involving the tendinous attachments of the physis (traction apophysitis) as well as overload to the long bone physis. Examples of traction apophysitis include the quadriceps mechanism on the tibial tubercle apophysis – Osgood–Schlatter disease – or with the patella tendon on the distal pole of the patella – Sinding–Larsen Johansson syndrome. Another common apophysitis involves the gastroc-soleus complex strain on the calcaneal apophysis referred to as Sever disease. Injuries to the long bone physis include the distal radial physeal injury in the young gymnast due to repetitive loading and physeal injuries such as Little Leaguer’s shoulder, which represents an injury to the proximal humeral physis due to traction and rotational stresses encountered during repetitive throwing. All of these injuries are unique to the developing athlete due to the susceptibility of the growth plate to injury during periods of rapid growth. Because the growth cartilage (physis) is the weak link in the developing joint – the physis may be two to five times weaker than the surrounding fibrous tissue ⁵ – it is more susceptible to shear and tension forces and is therefore less resistant than adjacent bone and ligament to injury. Consequently, a child is more likely to sustain a physeal injury rather than a ligament tear or joint dislocation, injuries commonly seen in adults. In fact, approximately 15 % of all fractures in children involve the physis. ^6,7