The Influence Of Different Marker Sets On Lower Extremity Dynamics During Walking

Abstract

PURPOSE: Two different marker cluster sets (heel plate, HP and dorsal plate, DP) have traditionally been used to track the foot during inverse dynamic calculations of the lower extremity, however, comparisons between these two methods have not been reported. This study examines the differences in sagittal and frontal plane lower extremity dynamics during the stance phase of gait when tracking the foot with HP and DP triads. METHODS: Eight subjects (5 males, 3 females) performed 3-5 trials of barefoot gait at their self-selected speed with DP and HP triads affixed to their dominant foot. The HP spanned the proximal, distal, and lateral calcaneus. The DP spanned the proximal and distal cuboid to the medial cuneiform. Mean peak joint angles and moments were compared using Paired-t tests. Coefficient of Multiple Correlation was used to analyze joint dynamics throughout the stance phase. RESULTS: Sagittal plane ankle kinematics (R=.846), as well as ankle (R=.868), knee (R=.811) and hip (R=.807) moments were strongly correlated between the two conditions throughout stance. There was a significant increase in peak plantar flexion (p<.01), knee flexion (p<.01) and hip flexion (p<.05) moments with the DP. Frontal plane ankle kinematics (R=.577), and ankle (R=.400), knee (R=.442) and hip (R=.582) moments were moderately correlated throughout stance. There was a significant increase in peak ankle eversion (p<.01), knee abduction (p<.01) and hip abduction (p <.01) moments with the DP. CONCLUSIONS: Use of a DP increases peak ankle plantar flexion and eversion angles, effectively altering kinetic calculations at the ankle, knee and hip in the sagittal and frontal planes. Caution should be taken when analyzing intra- and inter-study results that use different triad locations.