Influence of hip position on active and passive hip internal & external rotation

Abnormal joint mobility is an important factor in movement dysfunction and physical disability. A general lack of descriptive details exists for measurements of hip rotation range of motion (ROM). This study was designed to establish the influence of hip position on active and passive range of motion of the hip in external and internal rotation(Ext & Int Rot). Sixty healthy female college-age (22.17 +/- 1. 8 years) subjects were studied. Hip rotation of the legs of each subject was measured in the prone (hip near 0 degree of extension) and seated (hip near 90 degrees of flexion) positions using a standard goniometer. Data were analyzed using an analysis of paired-t-test and Wilcoxon, Mann-Whitney model. Pearson's r statistics were used to determine the reliability of measurements of hip rotation made in ext vs. flex (P<0.05, r>0.90). A statistically significant difference (p < 0.05) was found between mean hip Ext & Int Rot, active range of motion measured in ext vs. flx. Conversely, mean hip Ext & Int Rot, passive range of motion measured in ext or flx was not statistically different. Our data indicate that measurement position had a significant effect on the amount of active range of motion of the hip in Ext & Int Rot. Discussion & These findings are clinically significant for they stress the importance of documenting measurement position. They also stress the need for representative normal valves to be established for each hip position and gender. Our normal valves ROM values for the Int & Ext Rot of the hip calculated from this population based sample were found to differ from estimate found in textbooks. This may be due to young age and female groups and lifestyle of Iranian population, too.