Identification of mechanical consequences of jumper's knee by isokinetic concentric torque measurement in elite basketball players

Jumper's knee is a major reason of competition interruption for elite basketball players. This is due to the patellar tendinosis which explains knee pain and the decreased strength of knee extensors required for performing the jump. The aim of this study was to determine whether isokinetic parameters could identify competitive sportsmen who suffered from jumper's knee. The bilateral knee concentric strength of fifty seven elite basketball players was measured using a Cybex Norm isokinetic dynamometer at 60, 180 and 240 degrees/s and during a longer test (15 x 180 degrees/s). From this population, fifteen competitive basketball players with unilateral jumper's knee (Victorian Institute of Sport Assessment score: 62 12) were compared with 42 control cases (VISA score: 93 6). A knee extensors asymmetry at 60 degrees/s of more than 10% identified the injured basketball players and represented the more useful parameter (probability of 66%). The fatigue isokinetic test at 180 degrees/s was not informative. Injured athletes knee flexors strength was not different from the uninjured players. We conclude that concentric isokinetic evaluation of knee extensors at 60 degrees/s indicate knee extensors torque asymmetry which may play a role in jumper's knee pathology.