Foot posture is an important characteristic that can affect kinematics, plantar loading, and injury risk. Arch height is one common aspect of foot posture, and it is estimated that about 60% of the population has normal arches while 40% of the population is either pes planus or pes cavus. It is important to be able to accurately and reliably assess foot posture characteristics in order to propose interventions that could prevent injuries due to abnormal foot alignment. However, despite multiple classification metrics, many of the devices that are commonly used for foot posture measurements are not economically feasible for smaller clinics or research labs. Therefore, the first purpose of this study was to develop an affordable device to measure different foot posture characteristics. The Foot Posture Measurement System was developed and can measure total foot length, truncated foot length, foot width, dorsum height, and navicular height. This system was shown to have good to excellent validity (ICC = 0.908-0.994) and repeatability (ICC = 0.867-0.996) when compared to a 3D scanner. This device was then used in the second portion of this study, which evaluated the effects of ankle braces on plantar loading patterns in individuals with different foot postures. Contact area, peak force, force-time integral, and center of pressure were evaluated during a walk, run, and cut while the participant was unbraced, wearing a lace-up stabilizer brace, and wearing a semi-rigid brace. It was demonstrated that arch height did affect the maximum plantar forces during all tasks (p=0.001-0.047), as hypothesized based on previous studies. Additionally, this study found that ankle braces affected contact area (p=0.001-0.0014), maximum force (p<0.001 – p=0.043), and force-time integral (p<0.001 – p=0.015) during the walk, run, and cut. This is a novel finding and points to the potential for an impact of ankle braces on plantar loading during athletic activities, independent of foot type. / Master of Science / Foot posture is an important characteristic that can affect daily life and contribute to the risk of injury. Arch height is one common aspect of foot posture, and it is estimated that about 60% of the population has normal arches while 40% of the population is either high arched or low arched/flat footed. It is important to be able to accurately and reliably assess foot posture characteristics in order to propose interventions that could prevent injuries due to abnormal foot alignment. However, despite multiple classification metrics, many of the devices that are commonly used for foot posture measurements are not economically feasible for smaller clinics or research labs. Therefore, the first purpose of this study was to develop an affordable device to measure different foot posture characteristics. The Foot Posture Measurement System was developed and can measure five different length, width, and height characteristics of the foot. This system was shown to be valid when compared to a 3D scanner and repeatable between days. This device was then used in the second portion of this study, which evaluated the effects of ankle braces on individuals with different foot postures. Four different force and pressure variables were examined within the foot during a walk, run, and cut while the participant was unbraced, wearing a lace-up stabilizer brace, and wearing a semi-rigid brace. It was shown that arch height did alter plantar loading measures during all tasks, as hypothesized based on previous studies. Additionally, this study found that ankle braces affected all variables during the walk, run, and cut. This is a novel finding and points to the potential for an impact of ankle braces on plantar loading during athletic activities, independent of foot type.

African Americans (AA) are twice as likely as White Americans (WA) to experience diabetes-related foot amputation due to foot ulcers. Foot ulcers are often caused by high plantar pressure, and several factors can impact plantar loading. Thus, there is a need to determine if race is a significant predictor of plantar loading. Additionally, with the current state of racial health disparities there is a need to determine racial differences in research engagement and mistrust between AA and WA. Data was collected from 107 participants, aged 18-30, in this Institutional Review Board approved study. An EMED pressure-measurement system (Novel Electronics, St. Paul, MN, USA) was used to collect plantar loading data. Additional measurements collected from each participant included arch height index (AHI), standing height, gait speed, and weight. Participants also completed two surveys focused on research engagement and research mistrust. A multiple linear regression was used to test if race and other factors significantly predicted plantar loading. Non-parametric tests were used to test if there were significant differences in research engagement and mistrust between AA and WA. The analysis determined that race was a significant predictor for plantar loading, along with age, AHI, gait speed, sex, and body mass index (BMI). Additionally, it was found that research engagement practices and feelings of research mistrust differed significantly between AA and WA young adults. These findings could improve our understanding as to why AA are more likely to have diabetic foot ulcers than WA, and why AA are less likely to participate in research than WA. / M.S. / African Americans (AA) are twice as likely than White Americans (WA) to experience diabetes-related foot amputation due to foot ulcers. Foot ulcers are often caused by high plantar pressure, and several factors can alter plantar loading. Thus, there is a need to determine if race is a significant predictor of plantar loading. Additionally, with the current state of racial health disparities, there is a need to determine racial differences in research engagement and mistrust between AA and WA. Data was collected from 107 participants, aged 18-30. A pressure-measurement system was used to collect plantar loading data in seven regions of the foot during self-selected speed walking. The measurements collected from each participant, included arch height, standing height, gait speed, and weight. Participants were also asked to complete two surveys focused on research engagement and research mistrust. We used this data to evaluate if race and other factors predicted plantar loading and to compare survey responses between AA and WA. It was found that race, age, arch height, gait speed, sex, and BMI were considered significant predictor variables for plantar loading measures. Additionally, research engagement practices and feelings of research mistrust differed significantly between this younger sample of AA and WA. These findings help to improve our understanding of why AA are more likely to have diabetic foot ulcers than WA, and why AA are less likely to participate in research than WA, even as young adults.

BACKGROUND:People who have extremely high arched feet or pes cavus often suffer from substantial foot pain. Custom-made foot orthoses (CFO) have been shown to be an effective treatment option, but their specificity is unclear. It is generally thought that one of the primary functions of CFO is redistributing abnormal plantar pressures. This study sought to identify variables associated with pain relief after CFO intervention.METHODS:Plantar pressure data from a randomized controlled trial of 154 participants with painful pes cavus were retrospectively re-analyzed at baseline and three month post CFO intervention. The participants were randomized to a treatment group given CFO or a control group given sham orthoses.RESULTS:No relationship between change in pressure magnitude and change in symptoms was found in either group. However, redistribution of plantar pressure, measured with the Dynamic Plantar Loading Index, had a significant effect on pain relief (p=0.001). Our final model predicted 73% of the variance in pain relief from CFO and consisted of initial pain level, BMI, foot alignment, and changes in both Dynamic Plantar Loading Index and pressure-time integral.CONCLUSION:Our data suggest that a primary function of effective orthotic therapy with CFO is redistribution of abnormal plantar pressures. Results of this study add to the growing body of literature providing mechanistic support for CFO providing pain relief in painful foot conditions. The proposed model may assist in better designing and assessing orthotic therapy for pain relief in patients suffering painful cavus foot deformity.TRIAL REGISTRATION:Randomized controlled trial: ISRCTN84913516