Knee Pain, Teens, & Pre-teens
Knee pain is a common injury affecting one third of adolescents and causing disruption to their sports training & performances. (Rathleff et al, BJSM, 2015) The most common knee injury is Patella Femoral Pain Syndrome (PFPS). Girls are affected more than boys and adolescent girls are also affected with ACL injuries 2-10 times more than boys. (Myer, 2013).
Myer’s research paper also suggested that one of the major differences between girls & boys during a landing task was the overactivation of the quadriceps with decreased hip flexor activation in girls. This led to an increase in rotational forces at the knee, called knee abduction moments. Knee Abduction moments appear as a movement of the knee inwards or internally rotating over the planted foot. (see image) This is clearly visible during landing in volleyball, netball, and basketball.
Sports that involve cutting movements such as football and touch increase the force of Knee Abduction Moments (KAM) due to the higher speeds of landing and rotation in a single leg stance. The greater the increase in the KAM, the greater the risk of PFP & ACL injuries.
During maturation, boys had shown to have the opposite muscle activation to girls with an increased hip flexor activation. This higher activation of hip flexor muscles in the body could potentially balance the quadriceps activation & limit rotational forces at the knee. Myer also suggested that during maturation phases, girls with increased height and mass are more prone to earlier onset of PFPS.
Based on these findings and on the more widely known understanding of quadriceps involvement, students who are experiencing PFPS need to undertake a quad strength, and neuromuscular exercise plan. Most of these students will respond well to a specific & individualised program designed by a qualified health professional. They also need to relearn jump landing strategies, cutting movements, and single leg movement patterns for their sport. Sometimes other interventions such as footwear, and added support such as orthotics may be required if there are more specific anatomical and biomechanical issues.
A recent paper published this year in the British Journal of Sports Medicine found that additional exercise sessions done at school helped increase the recovery time for PFPS in adolescents. (Rathleff, 2015). These can be conducted by the sports educator / trainer as part of the warm up routine with the team. FIFA have thoroughly researched ways to reduce injury risk and have produced an exercise routine called FIFA 11+ that is readily accessible online.
As sports educators, coaches and trainers are usually the first person to recognise injury and or complaints of pain by adolescent sports girls & boys. It is worth talking to the students, and referring them for further investigation with the view that they will be given an appropriate strength program. Further helping them at training by including their exercises into the warm up routine is more likely going to keep your players on the field for longer and hopefully performing without pain, or with less pain throughout the season.
At intraining, we have a team of health professionals including podiatrists & physiotherapists who are experienced in treating sports related biomechanical injuries. Our clinicians understand the need to help students cope with the high loads of sporting commitments and injuries they experience. If you wish to discuss any concerns regarding injuries please contact us here.
Written by Margot Manning
Podiatrist, Level 2 Athletics Coach, Runner & Owner of intraining Running Centre
intraining Running Injury Clinic
1. Rathleff, M., Roos, E.M., et al. Exercise during school hours when added to patient education improves outcome for 2 years in adolescent patellofmoral pain: a cluster randomised trial. Br J Sports Med 2015; 49:406-412
2. Myer, D., Ford, K., et al. high knee abduction moments are common risk factors for patellofemoral pain(PFP) and anterior cruciate ligament (ACL) injuries in girls: IS PFP itself a predictor for subsequent ACL injury? Br J Sports Med 2015; 49:2 118-122
3. FIFA 11+