Comparison of a New Linear Instrument and the Gravity Goniometer for Assessing Knee Extension ROM among Children

The purpose of this study was to compare knee extension range of motion (ROM) as measured by a newly constructed linear instrument and by a gravity goniometer among children ages 8–14 years and to establish normative values for these children. The linear instrument recorded the distance in millimeters from the border of an uplifted heel to the measurement table. Coefficients of variation for knee extension were lower when linear measurement was used than with the gravity goniometer. The Pearson product moment correlation coefficient between the two methods of knee extension ROM was r = .79 (p < .001). Mean knee extension ROM was 13.2 ± 8.5 mm, or 2.8 ± 1.9°. Results of this study indicated that the constructed instrument was appropriate for assessing knee extension ROM and may be considered for use by rehabilitation specialists.