Date of Award
Doctor of Philosophy
Standard gait analysis using optical motion capture systems involves modeling the foot as a single segment which limits the information on inter-segmental foot motion. Foot models have been shown to be reliable, but limited research is available that uses these foot models in conjunction with shoes. There are methodology issues that arise when the subject is wearing a shoe.
The primary objective of this dissertation is to develop a method to analyze the relative motion of the foot bones within multiple shoes during a variety of activities. The secondary objective is to apply this method in clinical studies to investigate the effect on foot kinematics due to shoe modifications or during different movements. Before any clinical research could be conducted, three methodology studies needed to be performed. Firstly, a method for validating holes in the shoe was developed and used to demonstrate that a 2.5 cm hole is valid for three different shoe types. Secondly, static trials from four different shoe conditions were found to exceed a minimum important difference (5°). Consequently, single static trials are important from an injury perspective since the absolute angular range is calculated. Per-condition static trials are necessary, however, if the study objective is to examine the symmetry of the range of motion around the joint. Lastly, in a single-plane fluoroscopy study, soft tissue artifact (STA) was found to range from 6.46mm and 16.72mm for the hindfoot and midfoot triad markers, which was comparable to previous values found in literature.
Two clinical studies were then conducted and demonstrated that foot kinematics are influenced by a directional change but appear to be unaffected by a change in longitudinal torsional stiffness and forefoot flexion. Many possible hypotheses for these results are discussed, including the possibility that the foot has a pre determined kinematic pattern while traveling in a straight line that may be controlled by a pre-determined muscle activation pattern. The hypothesis that soft tissue is susceptible to injury past its “end-of-range” is also discussed in reference to foot injuries and the use of interventions. The method used in this dissertation will assist researchers in their investigations to find the mechanisms behind how the foot adapts to perturbations.
Shultz, Rebecca, "APPLICATION OF A MULTI-SEGMENT FOOT MODEL DURING RUNNING" (2009). Digitized Theses. 3797.