Author: Aliza Rudavsky on behalf of the IADMS Education Committee 

Our final injury prevention installment comes from Aliza, reporting early findings of a piece of research which has investigated patellar tendon development amongst adolescent dancers.  

Jumper's knee is a condition where there is pain just below the knee cap associated with jumping. The medical term for this condition is "patellar tendinopathy" and it is a fairly common condition in elite dancers, especially those who are strong jumpers and tend to jump a lot. Jumper's knee is an overuse condition. The main risk factor for developing symptoms is having pathology within the patellar tendon (pictured below). It is not clearly understood when pathology can develop in the tendon or when the tendon matures.  

A group of researchers from Melbourne are investigating how this tendon changes during adolescence in young ballet students. The goal of this study is to identify normal and abnormal tendon development. In order to observe changes in the tendon, this study involves using a 3-D ultrasound device called a UTC (Ultrasound Tissue Characterization) to image the patellar tendons of young ballet students at the Australian Ballet School and the Victorian College of Arts Secondary School throughout puberty. 

This research group will be following the same cohort of students over a two year period to monitor subtle changes in their tendons as they grow and progress through skeletal maturity. Dancing and other exercise volume is also being closely monitored as well as participation in classes and any injuries.  

The evidence so far has demonstrated that people with pathology in their tendons are at a much higher risk of developing jumper’s knee symptoms. Researchers have discovered already that after approximately 17 years old, tendons are mature and do not generally turn over new tissue; therefore, if people have pathology within their tendons by this age, it will likely remain within their tendons for life. This doesn’t mean they will definitely get jumper’s knee symptoms, however they are at a much higher risk than someone with completely healthy tendons. In younger dancers and athletes (pre-pubertal), the incidence of pathology on their patellar tendons is much more rare and it is thought that perhaps during these pubertal years where adolescents are surpassing their peak height velocity (peak height growth spurt) pathology can develop. Once we have a better understanding of how tendons mature normally during this time period, we may be able to gain some insight into abnormal tendon maturity. Throughout this study and in future studies, we hope to gain further understanding of the impact of loading this tendon before it has fully developed and clarify how much jumping is ideal for optimal tendon formation in order to reduce jumper’s knee in dancers and other jumping athletes.  

Aliza Rudavsky
Doctorate of Physical Therapy
PhD Student, University of Copenhagen