Resonance frequency in patellar tendon

The aim of this study was to the measure resonance frequency of the patellar tendon in order to determine whether the resonance frequency exists in the soft tissue of the human body. A vibrator was attached to the medial aspect of the tibia of 10 healthy subjects to provide different frequencies of vibration, and an accelerometer was attached to the patellar tendon to measure the vibration of the patellar tendon. Measurements were obtained at 0°, 60° and 90° of knee flexion. A mean resonance frequency of 22.5±0.8, 23.0+0.7 and 24.0+0.8 Hz was produced in the right patellar tendon when the knee joint was at 0°, 60° and 90° of flexion, respectively. The increase in resonance frequency from 0° to 60° was not statistically significant. However, the increase from 60° to 90° was significant (P<0.05). No differences in the measured parameters were evident for the left and right patellar tendons. These results indicate that resonance frequencies exist in soft tissues of the body and that this characteristic may be useful in detecting changes in soft tissue physical properties. ? 2007 Blackwell Munksgaard.