Tesi sul tema "Foot"

Background: The foot has to fulfil important and complex functions which are, in most regions of the world, supported by shoes. The interface of feet and footwear has often been considered with respect to comfort and function but also to negative effects of shoes. One main contribution to the improvement of footwear fit is provided by matching the shape of the shoe to the shape of the foot. However, current approaches for implementation only include static information. There is still a lack of dynamic information about foot morphology and deformation. Recent advancements in scanner technology allow capturing the foot during natural walking. These advancements and the development of a dynamic foot scanner system (DynaScan4D) are preconditions for this thesis. The research question is: How does foot morphology differ between static and dynamic situations? This question is further specified toward three hypotheses by findings and deficits of the current state of research. The examination of the three hypotheses and their contribution to the research question are topic of this thesis. Furthermore, the findings are combined with comprehensive knowledge of the literature to formulate recommendations for last and footwear construction. Methods: The three hypotheses (H1, H2, H3) are evaluated within three research articles. The first research article aims to identify the differences in dynamic foot morphology according to age, gender, and body mass (H1). The plantar dynamic foot morphology of 129 adults is recorded and analysed by two statistical methods: (1) comparison of matched groups and (2) multiple linear regression analysis. The second and third research article is dealing with differences between static and dynamic foot morphology in developing feet (H2) and their inter-individual differences (H3). For this reason, a large sample of 2554 children, aged between 6 and 16 years, is analysed. Foot measures, corresponding to last measures, are used to identify the differences between static and dynamic foot morphology (H2) by Student's t-test for paired samples. The influences of gender, age, and body mass (H3) are analysed within the whole sample by multiple linear regression analysis and within matched groups by Student's t-test for independent samples. Results: There are differences in dynamic foot morphology according to age, gender, and body mass in adults which confirm H1. In general, the differences are rather small. Furthermore, the differences must be considered in a more differentiated way, as they are not consistent regarding all plantar foot measures. H2 is confirmed as there are statistically signiffcant differences between static and dynamic foot morphology in developing feet. Theses differences are found for all foot measures. However, the magnitude of these differences varies depending on each foot measure. Relevant differences, in particular the forefoot width and midfoot girth measures as well as the angles of the forefoot, must be considered for footwear construction. Influences of gender, age, and body mass are found for the dynamic foot morphology and the differences between static and dynamic foot morphology of developing feet. Thus, H3 is verified. However, these findings are small, especially considering the high variance within each foot measure. The variables gender, age, and body mass cannot appropriately explain the variance of the differences between static and dynamic foot morphology. Thus, the customization of footwear to dynamic foot morphology can be conducted without individual adjustments to gender, age, or body mass. Conclusion: This thesis presents different aspects to answer the question of differences between static and dynamic foot morphology. The findings of this thesis are critically discussed and recommendations for improvements of dynamic fit of footwear are formulated, taking into account the current state of research as well as practical aspects. The findings of the thesis contribute to the field of fundamental research, i.e. to broaden the knowledge about three-dimensional characteristics of dynamic foot morphology. Furthermore, this thesis can help to improve the fit of footwear and thus contributes to applied research in the field of footwear science
Hintergrund: Der Fuß erfüllt wichtige und komplexe Funktionen, die in den meisten Regionen der Welt, durch Schuhe unterstützt werden. Die Berührungspunkte zwischen Schuhen und Füßen wurden im Hinblick auf komfortable und funktionelle Schuhe, aber auch hinsichtlich negativer Effekte von Schuhen, häufig betrachtet. Ein wesentlicher Beitrag zur Verbesserung der Passform von Schuhen liefert die Annäherung der Schuhform an die Fußform. Jedoch beschränken sich bisherige Umsetzungsansätze auf statische Informationen. Bislang fehlen umfangreiche dynamische Informationen zur Fußgestalt und Verformung. Erst aktuelle Fortschritte der Scanner-Technologie ermöglichen es, den Fuß während des natürlichen Gehens zu erfassen. Diese Fortschritte und die Entwicklung eines dynamischen Fuß-Scanner-Systems (DynaScan4D), stellen die Grundlage für diese Dissertation dar. Die Forschungsfrage ist: Wie unterscheidet sich die statische Fußgestalt von der dynamischen? Mit der Aufarbeitung von Ergebnissen und Defiziten aktueller Forschungsarbeiten wird diese Frage durch die Formulierung von drei Hypothesen weiter spezifiziert. Diese drei Hypothesen, sowie deren Beitrag zur Forschungsfrage, sind Thema dieser Dissertation. Darüber hinaus wird umfassendes Wissen aus der Literatur verwendet um Empfehlungen für die Konstruktion von Schuhen zu geben. Methoden: Die drei Hypothesen (H1, H2, H3) werden in drei wissenschaftlichen Veröffentlichungen untersucht. Die erste Veröffentlichung zielt darauf ab, die Unterschiede zwischen der dynamischen Fußgestalt in Abhängigkeit von Alter, Geschlecht und Körpermasse zu ermitteln (H1). Die plantare dynamische Fußgestalt von 129 Erwachsenen wird hierzu erfasst und durch zwei statistische Verfahren analysiert: (1) Vergleich von gepaarten Probandengruppen und (2) multiple lineare Regressionsanalyse. Die zweite und dritte Hypothese befassen sich mit den Unterschieden der statischen und dynamischen Fußgestalt bei heranreifenden Füßen (H2) und deren inter-individuellen Unterschieden (H3). Aus diesem Grund wird eine große Stichprobe mit 2554 Kindern im Alter zwischen 6 und 16 Jahren untersucht. Fußmaße, die den Maßen im Leistenbau entsprechen, werden verwendet um die Unterschiede zwischen der statischen und der dynamischen Fußgestalt (H2) durch einen gepaarten Student's t-Test zu identifizieren. Der Einfluss des Geschlechtes, des Alters und der Körpermasse (H3) werden in der gesamten Stichprobe durch eine multiple lineare Regressionsanalyse und innerhalb gepaarter Probandengruppen durch Student's t-Test für unabhängige Stichproben untersucht. Ergebnisse: Es gibt Unterschiede in der dynamischen Fußgestalt von Erwachsenen, beeinflusst durch Alter, Geschlecht und Körpermasse, welche die Verifizierung von H1 erlauben. Im Allgemeinen sind diese Unterschiede jedoch gering. Die ermittelten Unterschiede müssen differenziert betrachtet werden, da sie nicht konsistent in Bezug auf die gesamte plantare Fußgestalt auftreten. H2 kann verifiziert werden, da es zwischen der statischen und der dynamischen Fußgestalt von heranreifenden Kindern statistisch signifikante Unterschiede gibt. Diese Unterschiede wurden bei allen Fußmaßen gefunden, wobei das Außmaß dieser Unterschiede in Abhängigkeit vom jeweiligen Fußmaß variiert. Relevante Unterschiede, insbesondere Breitenmaße und Winkelmaße des Vorfußes sowie Umfangsmaße des Mittelfußes, müssen bei der Konstruktion von Schuhen berücksichtigt werden. Es zeigen sich Einflüsse von Geschlecht, Alter und Körpermasse auf die dynamische Fußgestalt sowie auf die Differenzen zwischen der statischen und der dynamischen Fußgestalt. Somit ist H3 verifiziert. Jedoch sind diese Einflüsse gering, besonders wenn die Varianz innerhalb der Fußmaße betrachtet wird. Die Variablen Alter, Geschlecht und Körpermasse können die Varianz der Differenzen zwischen der statischen und der dynamischen Fußgestalt nicht angemessen erklären. Damit kann die Anpassung an die dynamische Fußgestalt ohne eine Individualisierung hinsichtlich Alter, Geschlecht oder Körpermasse vollzogen werden. Schlussfolgerungen: Die vorliegende Dissertation stellt unterschiedliche Aspekte zur Beantwortung der Frage, welche Unterschiede zwischen der statischen und der dynamischen Fußgestalt bestehen, vor. Die Ergebnisse der Arbeit werden kritisch diskutiert und es werden, unter Berücksichtigung des aktuellen Forschungsstandes sowie praktischer Aspekte, Empfehlungen zur Optimierung der dynamischen Passform von Schuhen gegeben. Die Ergebnisse der Dissertation liefern einen Beitrag zur Grundlagenforschung, insbesondere durch die Erweiterung des Wissensstands der dreidimensionalen Eigenschaften der dynamischen Fußgestalt. Darüber hinaus kann diese Arbeit helfen die dynamische Passform von Schuhen zu verbessern und trägt damit zur angewandten Schuhforschung bei

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, February 2003.
Includes bibliographical references (leaves 81-85).
Drop foot, a loss of use of the muscles that lift the foot, can be caused by stroke, cerebral palsy (CP), multiple sclerosis (MS), or neurological trauma. The two major complications of drop foot are slapping of the foot after heel strike (foot slap) and dragging of the toe during swing (toe drag). The current assistive device is the Ankle Foot Orthosis (AFO), which though offering some biomechanical benefits, is nonadaptive and fails to eliminate significant gait complications. An Active Ankle Foot Orthosis (AAFO) is presented where the impedance of the orthotic joint is modulated throughout the walking cycle to treat drop foot gait. To prevent foot slap, a biomimetic torsional spring control is applied where orthotic joint stiffness is actively adjusted to minimize forefoot collisions with the ground. Throughout late stance, joint impedance is minimized so as not to impede powered plantar flexion movements, and during the swing phase, a torsional spring-damper (PD) control lifts the foot to provide toe clearance. To assess the clinical effects of variable-impedance control, kinetic and kinematic gait data were collected on two drop foot participants wearing the AAFO. For each participant, zero, constant and variable impedance control strategies were evaluated, and the results were compared to the mechanics of three age, weight and height matched normals. It was found that actively adjusting joint impedance significantly reduces the occurrence of slap foot, allows greater powered plantar flexion, and provides for greater biological realism in swing phase ankle dynamics. These results indicate that a variable-impedance orthosis may have certain clinical benefits for the treatment of drop foot gait compared to conventional AFO having zero or constant stiffness joint behaviors.
by Joaquin A. Blaya.
S.M.

The human foot has been accepted over the years as an important source of afferent input, used not only in the recognition of the surrounding environment (e.g. hard and soft surfaces), but also in the fine regulation of common daily-live movements (e.g. gait and balance control). The performance of these movements is usually accompanied by fluctuations in foot skin temperature as well as reciprocal blood flow changes at the foot area. Moreover, both variables are likely to be affected by footwear usage. Although these three factors are constantly present during the performance of daily live movements, only little and partially controversial information regarding the effects of foot skin temperature, blood flow at the foot area and footwear on foot sensitivity can be found in the literature. Therefore, the goal of the thesis was to investigate the effects of foot skin temperature, blood flow at the foot area and footwear on plantar foot vibration sensitivity of healthy young subjects. Three single studies were performed in order to investigate each variable separately. The first study investigated the influence of foot sole skin temperature on plantar foot sensitivity of 40 healthy subjects. Vibration thresholds were measured at 200Hz at a initial baseline temperature and after cooling/warming the foot skin 5-6 °C. The second study investigated the influence of short-time lower leg ischemia on plantar foot vibration sensitivity of 39 young adults. Lower leg ischemia was evoked with a pneumatic tourniquet, placed about 10cm above the popliteus cavity. Vibration thresholds were measured at 200 Hz in three different cuff pressure conditions: baseline (0 mmHg), low (50 mmHg) and high (150 mmHg). Finally, the influence of footwear on foot sensitivity was investigated in the third study, using specific Formula 1 shoes. Twenty-five male subjects participated in the study. Plantar foot vibration thresholds were measured at 30 and 200 Hz in five different foot/shoe conditions (barefoot and four shoe conditions). In all studies, vibration thresholds were measured at three anatomical locations of the plantar foot: heel, first metatarsal head (MET I) and hallux. The main results of the three studies show that the analysed variables significantly influence plantar foot vibration sensitivity. Data from the first study show that 5-6 °C alterations in foot skin temperature significantly influence the foot sensitivity of healthy young adults, whereby skin cooling results in reduced foot sensitivity, whereas skin warming improves plantar foot vibration sensitivity. The results of the second study indicate that short-time lower leg ischemia; especially regarding the high cuff pressure condition (150 mmhg), significantly reduces plantar foot sensitivity. Data from the third study show that the footwear effects on foot sensitivity are frequency-dependent. While barefoot sensitivity is better than shod sensitivity at 30Hz, shod sensitivity is better than barefoot sensitivity when measured at 200Hz. In conclusion, foot sole skin temperature, blood flow at the foot area and footwear significantly influence the plantar foot vibration sensitivity of healthy young adults. The alterations in foot sensitivity caused by these variables have important consequences for future clinical as well as movement-related research. Future clinical applications of quantitative sensory testing should consider the influence of these three factors during the assessment of sensory data, in order to standardize the measurement procedures as well as to enhance the quality of the collected data. Regarding the movement-related research, further studies should try to identify the importance of foot sensitivity for the performance of different types of movements (including sport-related activities). Additionally, the combined effects of movement-related changes in foot skin temperature and blood flow should be analysed and integrated in the development process of functional footwear, which is able to fulffill the foot sensitivity requirements of different movements
Die Rolle des menschlichen Fußes als wichtiger „Mediator“ sensorischer Reize wird zunehmen in der Literatur akzeptiert. Die vom Fuß aufgenommenen afferenten Informationen werden im Zentralen Nervensystem integriert und weitergeleitet, um die Regulation typischer Bewegungsmuster (z.B. Gang und Gleichgewichtskontrolle) mitzusteuern. Während der Durchführung derartiger Bewegungen werden oftmals Änderungen der Hauttemperatur oder auch des Blutflusses im Fußbereich provoziert. Diese werden wiederum durch das Tragen von Schuhen beeinflusst. Obwohl Hauttemperatur, Blutfluss im Fußbereich und Schuhwerk wichtige Faktoren bei der Bewegungsdurchführung darstellen, können nur wenige und teilweise konträre Informationen über den Einfluss dieser Faktoren auf die Fußsensibilität in der Literatur gefunden werden. Somit hat diese Dissertation zum Ziel, den Einfluss der Temperatur der Fußsohle, des Blutflusses am Fußbereich sowie des Schuhwerkes auf die Vibrationssensibilität des plantaren Fußes gesunder Probanden zu untersuchen. Um den Einfluss der einzelnen Parameter auf die Fußsensibilität untersuchen zu können, wurden drei Studien durchgeführt. Die erste Studie hatte zum Ziel, den Einfluss der Temperatur der Fußsohle auf die Vibrationssensibilität von 40 Probanden zu untersuchen. Dabei wurden die Vibrationsschwellen, - mit einer Frequenz von 200 Hz -, bei einer Ausgangsmessung sowie nach einer 5-6 °C Abkühlung/Erwärmung der Haut der Fußsohle gemessen. In der zweiten Studie wurde der Einfluss einer Kurzzeitischämie des Unterschenkels auf die plantare Fußsensibilität von 39 Probanden getestet. Die Ischämie im Unterschenkel wurde mit Hilfe eines im Bereich der fossa popliteal platzierten pneumatischen Tourniquets hervorgerufen. Die plantaren Vibrationsschwellen wurden mit einer Frequenz von 200Hz in drei verschiedenen Druckbedingungen ermittelt: Ausgang (0 mmHg), niedrig (50 mmHg) und hoch (150 mmHg). Schließlich beschäftigt sich die dritte Studie mit dem Einfluss vom Schuhwerk auf die Fußsensibilität. Fünfundzwanzig Probanden haben an der Studie teilgenommen. Die Vibrationsschwellen wurden mit Frequenzen von 30 und 200 Hz bei fünf verschiedenen Bedingungen gemessen (eine Barfuss- und vier Schuhbedingungen). In allen Studien wurden die Vibrationsschwellen im plantaren Fußbereich unter der Ferse, dem Metatarsalkopf I sowie unter dem Hallux ermittelt. Die Ergebnisse der drei Studien zeigen, dass die analysierten Parameter einen signifikanten Einfluss auf die plantare Vibrationssensibilität der Probanden haben. Die erste Studie zeigt, dass eine 5-6° C - Schwankung der Hauttemperatur der Fußsohle die Fußsensibilität signifikant beeinflusst, wobei die Erwärmung der Haut eine Zunahme der Fußsensibilität verursacht und die Abkühlung eine Abnahme der Fußsensibilität hervorruft. Die Ergebnisse der zweiten Studie demonstrieren, dass die im Unterschenkel hervorgerufene Ischämie eine Verschlechterung der Fußsensibilität verursacht, insbesondere bei den Messungen der Hochdruckbedingung (150 mmHG). Die Daten der dritten Studie weisen darauf hin, dass der Einfluss vom Schuhwerk auf die Vibrationssensibilität des plantaren Fußes frequenzabhängig ist. Bei einer Vibrationsfrequenz von 30Hz ist die Sensibilität barfuss besser als die mit Schuhen gemessene Vibrationssensibilität. Hingegen ist bei einer Frequenz von 200 Hz die mit Schuhen gemessenen Sensibilität besser als die Sensibilität barfuss. Anhand der Ergebnisse der drei Studien konnte festgestellt werden, dass die Temperatur der Fußsohle, Blutfluss im Fußbereich und Schuhwerk einen signifikanten Einfluss auf die plantare Vibrationssensibilität gesunder Probanden haben. Daraus folgen wichtige Hinweise für zukünftige klinische- sowie bewegungsorientierte Forschung. Der Einfluss der drei analysierten Parameter sollte künftig bei der Beurteilung sensorischer Daten mit einbezogen werden. Dies würde zum einem eine Standardisierung der Messverfahren gewährleisten, zum anderen die Qualität der im klinischen Bereich gemessenen Daten erhöhen. Im Rahmen bewegungsorientierter Forschung soll die Wichtigkeit der Fußsensibilität bei der Durchführung unterschiedlicher Bewegungsformen, auch sportlicher Bewegung, näher untersucht werden. Weiterhin sollte eine gemeinsame Analyse der bewegungsbezogenen Änderungen der Hauttemperatur bzw. des Blutflusses im Fußbereich in künftiger Forschung angestrebt werden. Folglich können diese Änderungen in die Entwicklung funktionellen Schuhwerkes eingesetzt werden, um den Anforderungen der Fußsensibilität bei unterschiedlichen Bewegungsformen möglichst gerecht zu werden

Research shows miners can be exposed to foot-transmitted vibration (FTV) when operating various pieces of underground mining equipment, and case reports suggest workers are experiencing symptoms similar to those of hand-arm vibration syndrome in their feet. A field study was conducted to measure and document FTV exposure associated with operating underground mining equipment, and probable health risks were determined based on both ISO 2631-1 (1997) for WBV and ISO 5349-1 (2004) for HAV. Seventeen participating operator’s also reported musculoskeletal discomfort. Seventeen male participants ranging between 24-61 years of age, with an average height and mass of 175.0cm and 88.2kg volunteered for the study. Seventeen pieces of equipment were tested; 1 locomotive, 1 crusher, 9 bolter drills (4 scissor platforms, 2 Maclean, 2 Boart/basket, and 1 RDH), and 6 jumbo drills. Including all seventeen pieces of underground mining equipment, the vibration acceleration ranged from 0.13-1.35m/s2 with dominant frequencies between 1.25-250Hz according to ISO 2631-1. According to ISO 5349-1 vibration acceleration ranged from 0.14-3.61m/s2 with dominant frequencies between 6.3-250Hz. Furthermore, the magnitude of FTV measured on the jumbo drills with grated platforms (#5 and #6) was less than FTV measured from the jumbo drills with, solid metal surfaces. Additionally, twelve of the seventeen equipment operators indicated a complaint of discomfort in their lower body (specifically at the level of the knee or lower). The health risk analysis based on ISO 2631-1 indicated that one operator (bolter drill #9) was exposed to vibration above the criterion value, while the health risk analysis based on ISO 5349-1 indicated iv that two operators (jumbo drill #1 and bolter drill #1) were exposed to vibration above the criterion value. Operators reported very severe or severe discomfort; however, the same operators were not the operators of the equipment with FTV exposure levels above the ISO standards, leaving evidence to suggest that the standards are not properly assessing injury risk to vibration exposure via the feet. Future research is needed to develop a standard specific for FTV and to determine the link between early musculoskeletal injury reporting and the onset of vibration white foot. To do so, a better understanding of the biodynamic response of the foot to FTV is needed. A laboratory study was conducted to 1) measure and document transmissibility of FTV from (a) floor-to-ankle (lateral malleolus), and (b) floor-to-metatarsal, during exposure to six levels of vibration (25Hz, 30Hz, 35Hz, 40Hz, 45Hz, and 50Hz) while standing, and 2) to determine whether independent variables (vibration exposure frequency, mass, arch type) influence transmissibility (dependent variable) through the foot. A two-way repeated measures analysis of variance (ANOVA) was conducted. There was a significant interaction between transmissibility location and exposure frequency (λ = 0.246, F (5,25) = 15.365, p = 0.0001). There were significant differences in mean transmissibility between the ankle and metatarsal at 40Hz [t(29) = 4.116, p = 0.00029], 45Hz [t(29) = 6.599, p = 0.00000031], and 50Hz [t(29) = 8.828, p = 0.000000001]. The greatest transmissibility at the metatarsal occurred at 50Hz and at the ankle (lateral malleolus) transmissibility was highest from 25-30Hz, indicating the formation of a local resonance at each location. v Future research should focus on identifying resonance frequencies at different locations on the feet. This information is needed to develop an exposure guideline to help protect workers from exposure to FTV, and to develop personal protective equipment capable of attenuating harmful FTV exposure frequencies.

The foot keeps body balance and stability during walking, running and performing various physical activities. It has been determined that mechanical properties of musculoskeletal system influence motion control, body balance maintenance (Richardson et al., 2005; Biewener, Daley, 2007; Nishikawa, 2007). However, it is yet unclear whether there is a relation between body stability and foot arch stability. The relation is yet unknown between the mechanical and physiological properties of the foot and foot arch stability. The aim of the research is to determine the relation between foot arch stability and the mechanical and physiological properties of the foot. The objectives of the research were: 1. To determine whether feet distribution according to arch type depends on different foot arch assessment methods applied. 2. To determine the mechanical properties of foot, Achilles tendon and plantar fascia. 3. To investigate whether there is a relation between foot arch stability and body stability. 4. To investigate whether there is a relation between mechanical and physiological properties of the foot. METHODS The research was carried out according to the principles of Convention on Human Rights and Biomedicine adopted on 19 November 1996 (Convention on Human Rights and Biomedicine) (Rogers and Bousingen, 2001). The license for the research was issued by Kaunas Regional Biomedical Research Ethics Committee (protocol No BE-2-53). 5 studies were conducted: 1 study: the analysis of... [to full text]
Žmogui einant, bėgant, atliekant įvairias fizines veiklas, pėda išlaiko kūno pusiausvyrą, stabilumą. Net mažas struktūros ar funkcijos pokytis gali turėti įtakos pėdos hiper-, hipomobilumui, kurie siejami su traumų atsiradimu. Šio darbo tikslas buvo nustatyti pėdos skliauto stabilumo ir mechaninių bei fiziologinių savybių sąveiką. Atlikti penki tyrimai. Pirmojo tyrimo tikslas – nustatyti, ar pėdų pasiskirstymas pagal skliauto tipus priklauso nuo skirtingų skliauto nustatymo metodų. Tyrime dalyvavo 91 tiriamasis ir buvo ištirtos 182 pėdos. Tyrime taikyti F. Forriol, L. T. Staheli, H. H. Clarke ir D. S. Williams pėdos skliauto nustatymo metodai. Gauti tyrimo rezultatai rodo, kad pagal skirtingas metodikas pėdos pagal normalų, žemą ir aukštą pėdos skliauto tipą pasiskirstė nevienodai. Antrojo tyrimo tikslas – nustatyti normalaus, žemo ir aukšto pėdos skliauto deformaciją, santykinę deformaciją ir standumą. Buvo tirtos 42 pėdos. Biomechaniniai pėdos parametrai apskaičiuoti naudojant pėdos gniuždymo metodiką. Nustatyta, kad pėdos deformacija ir standumas priklauso nuo pėdos skliauto tipo. Žemo skliauto standumas yra mažesnis ir jis daugiau deformuojasi negu normalaus ir aukšto pėdos skliautas. Trečiojo tyrimo tikslas – nustatyti in vitro pėdos deformaciją, santykinę deformaciją ir standumą esant skirtingam gniuždymo greičiui. Tirtos viena su minkštaisiais audiniais ir šešios be minkštųjų audinių pėdos. Tyrime pėdos buvo gniuždomos Tinius Olsen H25K-T bandymų mašina. Pėdos... [toliau žr. visą tekstą]

Introduction: Instrumented gait analysis and inverse dynamics are commonly used in research and clinical practice to calculate lower extremity joint kinetics, such as power and work. However, multisegment foot (MSF) model kinetics have been limited by ground reaction force (GRF) measurements. New technology enables simultaneous capture of plantar pressure and shear stress distributions but has not yet been used with motion capture. Integrating MSF models and pressure/shear measurements will enhance the analysis of foot joint kinetics. The purpose of this study was to develop methodology to integrate these systems, then analyze the effects of speed on foot joint kinetics. Methods: Custom software was developed to synchronize motion capture and pressure/shear data using measured offsets between reference frame origins and time between events. Marker trajectories were used to mask pressure/shear data and construct segment specific GRFs. Inverse dynamics were done in commercial software. Demonstrative data was from 5 healthy adults walking unshod at 3 fixed speeds (1.0, 1.3, and 1.6 m/s, respectively) wearing retroreflective markers according to an MSF model. Plantar shear forces and ankle, midtarsal, and first metatarsophalangeal (MTP) joint kinetics were reported. Speed effects on joint net work were evaluated with a repeated measures ANOVA. Results: Plantar shear forces during stance showed some spreading effects (directionally opposing shear forces) that relatively were unaffected by walking speed. Midtarsal joint power seemed to slightly lag behind the ankle, particularly in late stance. Net work at the ankle (p = 0.024), midtarsal (p = 0.023), and MTP (p = 0.009) joints increased with speed. Conclusions: Functionally, the ankle and midtarsal joints became more motorlike with increasing speed by generating more energy than they absorbed, while the MTP joint became more damperlike by absorbing more energy than it generated. System integration appears to be an overall success. Limitations and suggestions for future work are presented.

Major problems of the Foot Drop treatment are expensive and complex solutions. This work

presents the performance of a new inexpensive method named as Semi-Active Ankle Foot

Orthosis (SAAFO). The concept of this approach is to use inexpensive sensors to detect foot step

movement. The signals from the sensors afterwards will be fed to a control system of SAAFO in

runtime for a smooth foot movement of a drop foot patient while walking. Different sensors have

been studied in detail along with comparison to the proposed sensor system and mechanical

design. The signals from the sensors are used to detect different phases of human walking. These

sensors are placed at different positions on an orthosis and their signals are studied in detail.

Experiments have been done in different conditions to get a realistic picture either this assembly

can be implemented commercially. Signals are plotted and discussed yielding that the human

walking phases can be easily and accurately detected using inexpensive sensor assembly.

Rubble-strewn corridors, stairs and steep natural terrain all present a challenge for wheels and tracks. Legs are a solution in these cases because foot placement allows the traversal of discontinuous terrain. Legged robots, however, currently lack the performance needed for practical applications. This work seeks to address an aspect of the problem, foot placement while running. A novel hopping height controller for a spring-loaded legged robot is presented. It is simple and performs well enough to allow control of the ballistic trajectory of hops and therefore foot placement. Additionally, it can adapt to different ground properties using the result from previous hops to update control gains. A control strategy of extending the leg at a fixed rate during the stance phase and modulating the rate of extension on each hop was used to control the hopping height. The extension rate was then determined by a feed-forward + proportional control loop. This performed sufficiently well allowing the ballistic trajectory of hops to be controlled. In simulation, the spring-loaded inverted pendulum (SLIP) model was extended to include actuation and losses due to friction. The control strategy was developed using this model then, in a planar simulation, the controller was run to perform foot placement while running over a series of platforms which vary in their horizontal and vertical spacing. To experimentally validate and further develop the control strategy, a one-legged hopping robot, constrained to move vertically, was used. The leg had 2 links, hydraulically actuated hip and knee joints and a spring-loaded foot. Results showed that the controller developed could be used to perform hops of randomly varying size on grounds with different properties and while running on a treadmill at different speeds. As an aside, the dynamics of hydraulic actuators presented a problem for foot repositioning during flight using a simple PID controller. This was solved through the novel implementation, in hydraulics, of a `zero-vibration' (ZV) filter in a closed-loop. Simulation and experimental results demonstrating this are presented.

One major way that running style varies between individuals is how their foot strikes the ground (forefoot strike or rearfoot strike). Running generates a torque about the ankle that depends on the individual’s foot strike pattern, length of their plantar flexor moment arm, and force generated from the plantar flexor muscles. The foot strike pattern during running, gastrocnemii muscle thickness, and heel length (used as an approximation for plantar flexor moment arm) were determined in 41 runners. Forefoot and rearfoot strike runners had the same thickness of the gastrocnemii muscles. However, in comparison with sedentary walkers, the runners had thicker calf muscles. These results imply a “peak” muscle thickness seems to be attained by running. Runners with longer heels were more likely to use a forefoot strike running style, possibly due to a mechanical advantage in the generation of torque.

Hallux abductovalgus (HAV) is common foot deformity that is known to predominate in women and is often assumed to be linked to the use of inappropriate footwear. The predominance of the deformity in females has been demonstrated through many surveys across different populations. The highest prevalence of the deformity reported found 44 per cent of women affect whilst the highest prevalence in men reported a prevalence of 22 per cent. Although the condition is seen less frequently in children and barefoot populations, the female foot is still affected twice as often as the male foot in such groups, weakening the theoretical association between the deformity and footwear. A review of 100 radiographs of male and female feet found an association between the functional angle of the metatarsal head and HAV deformity and found that the female metatarsal head is more rounded than the male metatarsal head. There was no difference in the degree of metatarsus adductus (MA) deformity between males and females but in females, when the MA angle was greater than normal (24') an abnormal HAV angle was always seen. A good association was seen between the proximal articular set angle and the HAV angle that was similar for males and females. A three dimensional study of 100 bone-sets was undertaken using a technique not previously applied to this field of study. The bones of the medial column (talus, navicular, medial cuneiform and 1st metatarsal) were included. Several differences between in the shape of male and female foot bones were found including the more rounded metatarsal head shape in females. When the differences were considered together it was suggested that the medial column in the female foot would be more adducted that in the male foot and the resultant adducted position of the 1st metatarsal would predispose the female foot to HAV deformity. A study of 226 children was undertaken to investigate if a relationship between hypermobility and HAV deformity existed. A new assessment tool for measuring lower limb joint hypermobility was developed initially. No association between HAV deformity and lower limb hypermobility was found in healthy children, but a significant association was identified in children diagnosed with joint hypermobility. In a study of foot pressure measurements in 61 children, significant differences in the amount of pressure placed through the hallux, the speed of loading of the 1st metatarsal head and the position of the centre of force through the foot were found between males and females. Associations with the pressure measurements and increasing joint flexibility were only seen for extreme levels of hypermobility. No association between HAV and plantar pressure was found.

Complications of type 2 diabetes mellitus are one of the major causes of morbidity and mortality around the world. Diabetic foot infections remain one of the major complications leading to a leg loss every 3 seconds due to amputations causing mental trauma and distress. In diabetic foot ulcers aerobes, anaerobes and fungus often interact with each other and form biofilms which is difficult to treat, enhancing antimicrobial resistance and lead to a non-healing ulcer. Co-existing peripheral vascular disease and neuropathy exacerbate the problems. In T2DM patients’ minor cuts and wounds, often lead to hard to treat and chronic ulcers which can worsen to gangrene formation which may lead to osteomyelitis compromising the mechanics of the foot. It is necessary to identify the virulence factors of these clinically significant microbes and to identify the resistance patterns regularly to limit the antibiotic usage and target to the specific organisms. A Cohort studies were carried out in India and in the UK to identify the risk factors among the diabetic foot patients along with their microbial aetiology and antibiotic resistance patterns from the tissue and pus samples. This part of the research has shown the presence of mixed cultures mainly from the Indian diabetic foot ulcer specimens with higher percentages of anaerobes than aerobes. Multi-drug resistant organisms were one of the peculiar characteristics of the diabetic foot ulcer profiles of Indian patients. As compared to the Indian patients, UK patients had few resistant organisms and the patients admitted to hospitals in India were at the last stage of foot ulcers whereas in the UK, surveillance and preventative strategies allow early detection and intervention. Currently there is a lack of rapid, robust and an inexpensive diagnostic method for the rapid typing and identification of clinically significant anaerobes. Another part of the research focussed on utilising the glycan-lectin interactions by developing a simple enzyme linked lectin sorbent assay by employing biotinylated lectins to develop to an enzyme linked lectin sorbent assay (ELLA) on whole cells, Proteinase K treated cells and glycolipids of clinically significant aerobes and anaerobes. This study is concluded by utilising the glycan-lectin interactions and to develop a rapid typing method for clinically significant Methicillin resistant and sensitive Staphylococcus aureus and epidermidis species. The rapid identification of anaerobes and typing of Peptostreptococcus species was also by facilitated by the developed ELLA method. Finegoldia magna is one of the most significant anaerobes from soft tissue infections and the Gas Chromatography – mass spectrometry (GC-MS) of the glycolipids of Finegoldia magna on composition analysis using show the presence of sialic acid which could be involved in pathogenesis. This sugar may be one of virulence factor employed by this organism in either attachment to the host or to other organisms.

This thesis reports on work undertaken to study the biomechanics of the human foot during normal daily activity, particularly walking and standing. A literature review is presented on topics related to the subject and several of the areas demanding further investigation are highlighted. Three lines of enquiry were pursued to consider the kinematics, kinetics, passive structural properties and muscle activity associated with the foot. A dynamic pedobarograph with a synchronised video system was used to measure the forces and their distribution under the foot (based on seven marked areas) and six kinematic angles of the foot and lower leg. Sixty-one healthy subjects were assessed and the results are presented. Kinetic and kinematic parameters were found to be consistent and smooth for the test population. Several of the events of the gait cycle were found to be temporally different from values widely reported. In the second investigation, four cadaveric foot specimens were tested dynamically to determine the role of the plantar structures during loading in various positions. A method of sequential dissection was used and the results support many of the theories regarding ligament function. Tests on the effect of three extrinsic muscles on the foot load distribution also support previous studies while a preliminary investigation of two pathological feet partially clarifies the biomechanical effects of a hallux valgus deformity. Eight of the foot extrinsic and intrinsic muscles were assessed for the final investigation. Using electromyographic (EMG) recording techniques on six healthy subjects, the muscle EMG activity was quantified during walking a) barefoot, b) with a moulded heel plate, and c) with soft shoes. The results for the extrinsic muscles generally agree with previous work, while the intrinsic muscle activity is more variable. The intrinsic muscles were more active when shoes were worn and displayed unusual fatigue patterns.

During a surveillance programme all the known diabetics (1150) were identified from a general population of 97,034 representing all patients registered with 10 general practices. A control group of 751 non-diabetic subjects were also drawn from the same general population. A single observer reviewed 1077 (93.6%) of the diabetics and 480 (69%) of the controls. Peripheral vascular disease was detected using doppler ankle/brachial pressure index in 20.6% (95% CI 18.2-23.0) of diabetics and 9.6% (95% CI 7.0-11.2) of controls. There was no significant difference between the prevalence in non-insulin dependent and insulin dependent diabetics after adjusting for age. The prevalence in either type of diabetes was however significantly greater than in controls. Multiple logistic regression analysis revealed that age, cerebrovascular disease, coronary artery disease, mean systolic blood pressure, blood glucose, proteinuria and serum cholesterol were significantly and independently associated with the presence of peripheral vascular disease in diabetics. Body mass index was inversely associated. For controls only age and smoking were found to be significant variables. Neuropathy determined by clinical evaluation and sensory vibration thresholds was found in 16.8% (95% CI 14.6-19.0) of diabetics and 2.9% (95% CI 1.4-4.3) of controls (p