Sex differences and discriminative value of lower extremity alignments and kinematics during two functional tasks

The purpose of this study was to formulate a predictive equation to discriminate males from females using static and dynamic lower extremity (LE) alignments. Twenty-four healthy adults volunteered to participate. Three-dimensional motion analysis was used to assess the kinematics of the right hip and knee during two functional tasks. Six measures of static LE alignment were also performed. Statistical comparisons were made between males and females for all variables. Static and dynamic variables that were significantly different by sex were entered into separate discriminant analyses for each task. The resulting equations were each able to correctly predict 87% of the subjects by sex. Fifty-eight percent and 55% of the variance was explained by sex for the vertical jump and plant & jump, respectively. The frontal plane hip angle was the best predictor of sex for both tasks. While there were statistically significant differences between the sexes for static measures of LE alignment, kinematic measures were better at discriminating between sexes.