Measurement of Tissue Hardness for Evaluating Flexibility of the Knee Extensor Mechanism

Hiroaki Kinoshita, Shumpei Miyakawa, Naoki Mukai and Ichiro Kono

[Received August 21, 2006 ; Accepted November 15, 2006] 

The knee extensor mechanism (hereafter referred to as the KEM) is one of the most common sites for overuse disorder that occurs in football players. The KEM overuse disorders, such as patellar tendinitis and Osgood-Schlatter’s disease, are assumed to be related to decreased flexibility in the KEM. Although it is important to check the KEM flexibility for the prevention of overuse disorders, a simple and quantitative measurement has yet to be established. The present study is an attempt to use a tissue hardness meter to evaluate the KEM flexibility. Under the assumption that elongation of the KEM due to knee flexion would increase the KEM tissue hardness, the relation between length and tissue hardness of the KEM in 40 knees of 20 healthy adults was investigated. Subjects were measured for their KEM length and their tissue hardness at the midpoint of the KEM using a tissue hardness meter in five knee positions: knee extended, knee flexed at 30, 60, 90 degrees, and knee fully flexed. There was significant positive correlation between length and tissue hardness of the KEM. In conclusion, the KEM flexibility can be evaluated by the measurement of tissue hardness.

Keywords: sports injury, knee extensor mechanism, tissue hardness, overuse disorder, prevention

[Football Science Vol.4, 15-20, 2006]