An Alternate Method of Range of Motion Measurement

The goniometer is certainly the most popular instrument to use for measuring joint range of motion in a clinical setting. However, this method of measurement does have its limitations, namely, problems with intertester reliability and with the fact that the device does not provide an accurate measure of inherent movement variability. Modern motion tracking devices such as the Flock of Birds can eliminate such problems. A simple experiment comparing the 2 measurement devices was performed, in which subjects, with their eyes closed, executed knee extensions (trying to match a passive measurement) of 45° and 60°. A statistically significant difference between the Flock and the goniometer was observed in the passive measurements of the 45° movement, possibly indicating the superiority of the modern device for quantifying movement variability. This finding may have practical clinical implications for determining recovery from a joint injury.