THE EFFECTS OF PROLONGED RUNNING ON THE BIOMECHANICS AND FUNCTION OF THE FOOT AND ANKLE

Running injuries have been linked to morphology and lower limb function, and changes in foot and ankle biomechanics and function within a run may contribute to the predisposition to injury. This thesis investigates the effects of prolonged running on the foot and ankle, and potential mechanisms underlying changes in foot posture. Methods: A series of studies were undertaken from field to laboratory, measuring foot posture changes after prolonged running of different durations. Further measures of ankle invertor strength and medial ankle stiffness were taken in the laboratory studies as well as kinematic and plantar pressure data captured every ten minutes to enable repeated measures analysis of pedal movement to be conducted. Reliability across the foot posture, strength and stiffness measures was also determined. The latter studies involved the development and mechanical testing of a novel foot orthosis component which was compared to a standard open cell orthotic foam. A double blind randomised controlled trial then compared how the novel and standard foam components affected foot posture, ankle invertor strength and medial and plantar soft tissue stiffness after a 30-minute run. Results: A mean drop in NH and increase in FPI-6 following the half marathon, hour long and 30-minute treadmill runs was seen, with changes decreasing as running duration reduced. Ankle invertor strength and medial ankle stiffness reduced but did not correlate to the change in foot posture. Changes in foot and ankle kinematics were seen within 30 minutes of running. Mechanical testing of the novel orthotic component and standard foam revealed characteristic differences in response to loading, and changes in foot posture measures after 30 minutes of running in the randomised controlled trial were almost identical across both conditions. Further comparison of invertor strength and medial foot and ankle stiffness revealed no significant differences, but a large difference between exertion measures was seen. Conclusion: There was an overall effect of duration of running on changes in foot posture in this thesis, and the foot posture change was moderated by two different foot orthosis conditions although the mechanism remains unclear.University of Plymout

The Effect of Barefoot Running on Navicular and Pelvic Drop: A Randomized Controlled Trial

Background and Purpose: Gaining knowledge of the change in navicular drop of the foot and pelvic movement in response to barefoot running training may allow sports medicine professionals, coaches, athletes, and others in the healthcare field to decrease the amount of injuries that may be caused by these motions. Effects of a running training program with conversion from a rearfoot strike pattern (RFSP) to forefoot strike pattern (FFSP) to determine impact on navicular drop and pelvic movement is lacking in literature. Due to the increased correlation of hip movement and lower extremity injuries, the purpose of this study was to determine if barefoot running training, with a FFSP compared to shod running using a RFSP, would affect the amount of drop during walking and running activities. Material/Methods: Navicular and pelvic movement was analyzed between shod and barefoot running groups by utilizing the VICON motion analysis system and the static navicular drop test before and after the six-week running program. This study implemented a six-week training program to convert from a RFSP to FFSP in the barefoot running group when compared to the controlled shod group. The VICON was specifically used to evaluate the pelvic movement and navicular drop of the foot during the stance phase of gait in walking and running. A decrease in navicular distance traveled from pre- to post-test, may suggest a decrease in dynamic foot over-pronation. This result could support the effects of barefoot running with a FFSP, as a method for reducing pain and injuries associated with running. Results: Results showed no statistical significance in the Standard Navicular Drop Test. There were no statistically significant differences using the VICON Motion Analysis for assessing dynamic navicular drop or pelvic movement in Barefoot Walking (BW) and Running Barefoot with a forefoot strike pattern (BR). However, trends indicated that post 6 week training the barefoot training group showed decreased navicular drop and decreased pelvic movement in comparison to the shod training group. Discussion: Barefoot running training did not illustrate statistically significant improvement in navicular drop or pelvic drop movement during this study. Data showed that navicular drop presented a trend towards having less movement during barefoot running and barefoot walking post training program in comparison to the shod running group. Due to the limitations of this study (small sample size, narrow population, limited time spent barefoot running training, and specifics of the VICON motion analysis process) future research could address these limitations through conducting an ongoing study and/or open it to the public to improve subject population

The Effect of Three Foot Orthoses on Plantar Pressure Under the First Metatarsophalangeal Joint of Pes Planus Foot Type During Standing and Slow Running

The purpose of this study was to examine the effect of three different foot orthoses on plantar pressure under the first metatarsophalangeal joint during standing and slow running. Twenty physically active participants, 12 males (19.7±1.3 years, 181.5±6.3cm, 83.6±12.3kg) and 8 females (20.8±1.5 years, 172.7±11.2cm, 69.9±14.2kg) with navicular drop greater than 10mm, no history of surgery to the lower extremity, and no history of pain or injury to the 1st metatarsophalangeal joint in the past six months volunteered for the study. Each subject performed standing and slow running tasks with four different orthosis conditions: no orthosis, metatarsal dome, U-shaped orthosis, and donut-shaped orthosis. The Pedar in-shoe pressure measurement system was used to examine the effects of each orthosis peak and mean pressure under four areas of the foot: rearfoot, lateral forefoot, medial forefoot, and the first metatarsophalangeal joint. Data were collected using Pedar-X Expert software and exported into an Excel spreadsheet for analysis. Separate 2X4X4 repeated measures ANOVAs were used to analyze peak plantar pressure and mean plantar pressure. The metatarsal dome significantly decreased peak running pressure compared to no orthosis and the donut-shaped orthosis, as well as mean standing and running pressure compared to all orthosis conditions. The U-shaped orthosis significantly reduced mean running pressure compared to no orthosis. The donut-shaped orthosis significantly increased peak and mean standing pressure compared to all orthosis conditions; it similarly significantly increased peak and mean running pressure compared to the metatarsal dome and U-shaped orthosis. Findings suggest that the metatarsal dome is most effective in reducing both peak and mean plantar pressure during standing and slow running. Further research is needed to examine the application of these results to other foot types as well as symptomatic individuals

A 3D image-based measurement approach for analysing dynamic foot posture and mobility

The original contribution achieved from this research was the development of a low-cost 3D high-accuracy photogrammetric technique for measuring dynamic changes in foot anthropometry during gait. In clinical settings, the approach of determining foot mobility is achieved through measuring changes in bone landmarks between the static unloaded foot and the static loaded foot. From previous reliability assessment tests, it was found that static clinical foot mobility assessments based on the dorsum bone as a point of landmark reference provides high levels of measurement reliability. However, the relationships between these static dorsum measurement techniques have not been assessed against dynamic dorsum measurements collected during foot mobility. In this thesis, two assessment techniques based on the dorsum as a point of reference; namely the Foot Mobility Magnitude (FMM) and Arch Height Index (AHI) were compared statically and dynamically. The purpose for this was to validate these static measurements against the actual foot mobility during dynamic activities. An imaging platform was developed which consisted of 12 video cameras synchronised with force plate data to continuously capture the foot during gait while simultaneously obtaining ground reaction force information. The developed system achieved measurement accuracies within 0.3 mm with high levels of measurement precisions and insignificant random and systematic errors. From the research study, it was found that the correlation between the static and dynamic FMM measurements was insignificant, whereas significant correlations were found between the static and dynamic AHI measurements. Agreements between the static and dynamic AHI measurements were higher when the dorsum measurements were normalised to the truncated foot length (AHI 1) than normalising the dorsum measurements to the total foot length (AHI 2). Another major finding from the research was the higher measurement correlations achieved when the dynamic FMM and AHI were assessed between heel-strike and mid-stance compared to between heel-strike and active propulsion. This indicates that measuring the static FMM and AHI between 10% WB and 50% WB instead of between 10% WB and 90% WB might lend better insight in determining the behaviour of the foot dynamically. The Foot Posture Index (FPI) was used to classify foot postures and the relationship between the FPI scores and the dynamic FMM and AHI were assessed. It was found that the FPI was significantly correlated to the AHI measures but no correlation was found between the FPI and the FMM. The highest correlation was found for AHI 1 at active propulsion where the FPI predicted 48.9% of the variation of the AHI 1. The only FPI classification criteria to have a significant influence on the AHI at heel-strike, mid-stance and active-propulsion was the congruence of the MLA with the highest prediction of 66.7% of the variation in the AHI 1 at heelstrike

DIFFERENCES IN ARCH INDEX, REARFOOT PLANTAR PRESSURE, AND FOREFOOT DEVIATION FROM CENTER OF FORCE TRAJECTORY IN THOSE WITH CHRONIC ANKLE INSTABILITY, NO HISTORY OF LATERAL ANKLE SPRAIN, AND COPERS.

The purpose of this study was to investigate differences in arch index, rearfoot plantar pressure, and forefoot deviation from center of force trajectory in those with chronic ankle instability, copers, and no history of lateral ankle sprain. A total of fifty-seven subjects from the local community volunteered for this study. There were 20 subjects in the CAI group (age, 20 ± 3 years; height, 173.61 ± 7.84 cm; mass, 73.91 ± 17.58 kg), 20 subjects in the control group (age, 20 ± 1 years; height, 169.90 ± 9.50 cm; mass, 64.53 ± 14.01 kg), and 17 subjects in the copers group (age, 20 ± 2 years; height, 171.34 ± 7.75 cm; mass, 71.18 ± 13.00 kg). Each subject completed one session of testing in which they walked barefoot across pressure mats at a self-selected speed. The composite footprint of each trial was then divided into rearfoot, midfoot, and forefoot for arch index (foot contact area), medial and lateral rearfoot for medial/lateral rearfoot pressure ratios, and then center of force trajectory deviation from a bisection line in the forefoot. The mean of three trials was used for statistical analysis. Each dependent variable (arch index, medial/lateral rearfoot pressure ratio, and forefoot deviation of center of force trajectory) was analyzed through separate 1-way ANOVA, with 1 between-subject factor (CAI, copers, and control) and a Chi-square Test of Independence. Alpha was set at p < .05. For arch index, a one-way ANOVA yielded no significant differences between the three groups (F2,54 = 0.26, p = 0.77, p2 = 0.01, power = 0.09). A Chi-Square test of independence was calculated comparing the categorical foot types between the three groups, which showed no significant differences (2(4) = 6.59, p = 0.16). For rearfoot medial/lateral pressure ratio, a one-way ANOVA yielded no significant differences between the three groups (F2,54 = 0.69, p = 0.50, p2 = 0.03, power = 0.16). A Chi-Square test of independence was calculated comparing the categories of medial versus lateral rearfoot pressure between the three groups, which showed no significant difference (2(2) = 4.80, p = 0.09). For maximal forefoot deviation from center of force trajectory, a one-way ANOVA yielded no significant differences between the three groups (F2,54 = 1.19, p = 0.31, p2 = 0.04, power = 0.25). A Chi-Square test of independence was calculated comparing the categories of medial versus lateral rearfoot pressure between the three groups, which revealed no significant difference (2(4) = 2.77, p = 0.60). These results of the statistical analysis revealed no significant differences between the three groups in regards to arch index, medial/lateral rearfoot pressure, or forefoot deviation from center of force trajectory. Since these dependent variables may not contribute to the development of chronic ankle instability, other factors such as proprioceptive deficits and neuromuscular differences may play a greater role. Therefore, clinicians should work on improving proprioception and strengthening of the ankle joint rather than focusing on foot type or locations of plantar pressure.Submitted to the faculty of the University Graduate School in partial fulfillment of the requirements for the degree Master of Science in Kinesiology in the Department of Kinesiology of, Indiana Universit

In-Vivo Investigation of the Medial Longitudinal Arch of the Foot and Orthotic Interactions using Bi-Planar Fluoroscopy

Orthotic devices are a conservative treatment for common disorders of the foot and ankle such as pes planus and pes cavus. It is thought that orthotics change the kinematics of the foot by applying forces and constraint on the plantar surface, which can act to change body biomechanics and correct for malalignment in the legs and trunk. This thesis compares the angle of the medial longitudinal arch (MLA) between three foot types: pes planus (low arch), pes cavus (high arch) and normal arch, during barefoot and shoed walking, and walking with orthotics. In-vivo bi-planar fluoroscopy was used with markerless radiostereometric analysis (RSA) to measure an angle that defines the MLA with the greatest accuracy to date. MLA angles were significantly smaller (

The effect of unsupportive and supportive footwear on children’s multi-segment foot dynamics during gait

Footwear is necessary for children’s foot comfort and protection. Despite the popularity of flip-flop (thongs) footwear among children, strong clinical opinion endures of the potential deleterious effect this footwear may have on developing feet. On the contrary, thongs may be beneficial for children’s developing feet due to the footwear’s flexible and unrestrictive nature, as children who mature within habitually barefoot communities are observed to develop stronger and healthier feet. This thesis considers the developing nature of human ambulation and the physiological basis for children’s foot maturation. It then explores the effect of thong footwear on childrens barefoot dynamics with comparisons to traditionally advocated supportive footwear. Foot compensations were observed when thongs were worn while walking and to a lesser extent while jogging. Greater ankle dorsiflexion and reduced hallux dorsiflexion suggests a mechanism to retain the thong. Greater midfoot plantarflexion indicates a gripping action to sustain the thong. Barefoot motions were unaffected by thongs during the sidestep. The midfoot splinting effect of supportive shoes was reinforced while walking, jogging and sidestepping. Thongs had a minimal effect on barefoot dynamics, while supportive shoes limited midfoot power generation with a corresponding increase in ankle power generation. Overall findings suggest that foot motion when wearing thongs may be more replicable of barefoot motion than originally believed. In terms of foot arch development, thongs may be more beneficial than supportive shoes, due to the minimal alterations to barefoot motions when they are worn. The reported midfoot plantarflexion required to grip the thong may be beneficial to children’s foot arch strengthening and overall foot development. While supportive shoes have the necessary protective features, they have been shown to inhibit midfoot and hallux motions with a compensatory increase in ankle motions

Medial longitudinal arch mechanics before and after a prolonged run

Collapse and reformation of the medial longitudinal arch during gait is controlled passively and actively. If either tissue group fatigues over the duration of a run, the change in arch mechanics may increase risk of running injuries. However, a 3-dimensional kinematic analysis of the medial longitudinal arch after a prolonged run has not been performed. Additionally, rarely has arch collapse been quantified for walking and running in the same study. PURPOSE: To compare arch mechanics before and after a 45 minute run and to compare walking and running arch deformation. METHODS: Thirty runners performed barefoot walking and running trials before and after a 45 minute treadmill run. Reflective markers were placed on the foot and lower limb. Arch lengthening, navicular displacement, and arch height index quantified arch motion. Arch rigidity index and dynamic arch stiffness, a new measurement, quantified resistance to collapse. RESULTS: There was a significant gender y time interaction for arch rigidity index, decreasing after the run for men and increasing for women. There was no main effect for either time or gender for any other dependent variable. Walking and running, however, were significantly different for all relevant variables. Arch collapse was significantly greater for running than walking. CONCLUSION: The structures of the medial longitudinal arch of the foot may have adapted to the cyclical loading of the run by recruiting other muscles, or the arch may be resilient to change after a non-exhausting run. Greater arch deformation during running was likely a function of increased plantarflexion moment and ground reaction forces compared to walking