Sammanfattning Att undersöka en befolknings fysiska aktivitet ger beskrivande data utav dagsläget samt att resultatet fungerar som mätinstrument för hur en framtida intervention ska utformas. Syftet med denna studie var att se om något samband förelåg mellan tre olika undersökningsinstrument för fysisk aktivitet, som används för med barn med övervikt. Metod: Deltagarna mättes, vägdes, skattade sin fysiska aktivitetsnivå (frågeformulär), testade sin fysiska prestationsförmåga (sex minuters gångtest) och deras fysiska aktivitet mättes (accelerometer). Resultat: Åtta flickor, 7-13 år, med ett Body Mass Index (BMI) på 26 ± 3,7 kg/m2deltog. Majoriteten skattade sig vara fysiskt aktiva 30-60 min/dag under vardag och helg, men som grupp var skattningen signifikant lägre på helgen. Deltagarnas fysiska prestationsförmåga var signifikant lägre än det beräknade normalvärde. Barnen utförde i snitt 67 ±24 min/dag aktivitet under vardagarna och signifikant mindre aktivitet (31 ± 29,7min/dag) på helgerna. Ett signifikant samband förelåg mellan undersökningsinstrumenten för utförd fysisk aktivet under vardagarna och prestationsförmågan, där även en formel för hur sambandet kunde kalkyleras framtogs. Slutsats: Trots litet deltagarantal skulle studiens resultat tyda på att 6MGT kan användas inte bara för att bedöma prestationsförmåga utan även för beräknad utförd fysisk aktivitet under vardagarna. / Abstract Investigation physical activity in a population gives descriptive data and the result serves as a measuring instrument for how future interventions ought to be designed. The purpose of this study was to see whether any associations existed between three examination instruments for physical activity that are used with children with overweight. Method: The participants were measured, weighed, estimated their physical activity (questionnaire), testing their physical performance (six-minute walking test) and their physical activity was measured (accelerometer). Results: Eight girls, aged 7-13, body mass index of 26 ± 3.7, participated. The majority of the children estimated to be physically active for 30-60 min/day, during weekdays and weekends, but seen as a group the estimation was significantly lower on the weekend. Their physical performance showed a significantly lower value than the predicted value. The children performed on average for 67 ± 24 min / day during the week and significantly less (31 ± 29.7 min / day) on weekends. A significant association existed between performed physical activity during weekdays and the performance test. A formula for how this relationship could be calculated was designed. Conclusion: Despite low numbers of participants the result of the study could indicate that 6MWT can be used not only for assessing the performance but also to calculate the executed amount of activity during weekdays.

Regular walking has several physical and psychological benefits for frail older people. However, many residents in long-term care facilities are too sedentary to achieve these benefits. Indoor walking appears to be a feasible way to promote active living among these residents and yet, there is little research that has been done in this regard. The researcher conducted two studies in Central Texas to explore how corridor design features influenced indoor walking behaviors among assisted living residents. In the first study, the researcher carried out six focus groups with 50 assisted living residents, discussing how they perceived the indoor corridor as "walkable." Residents reported that a walkable corridor should be safe, comfortable, and having beautiful/interesting things to see. In the second study, the researcher further examined the relationship between the built environment and walking behaviors among 326 residents from 18 facilities in a major city of Texas. The results indicated that 'perceived looped corridor' and 'number of stories' were significantly associated with residents' frequencies of indoor recreational walking. In addition, the availability and quality of sitting space around mailbox areas influenced the number of "walking to mailbox" trips. This research provides empirical evidence to develop activity-friendly facility design guidelines, and to create environmental interventions to facilitate active lifestyles among long-term care residents.

This thesis poses a feedback control method for obtaining humanlike bipedal walking on a human-inspired hybrid biped model. The end goal was to understand better the fundamental mechanisms that underlie bipedal walking in the hopes that this newfound understanding will facilitate better mechanical and control design for bipedal robots. Bipedal walking is hybrid in nature, characterized by periodic contact between a robot and the environment, i.e., the ground. Dynamic models derived from Lagrangians modeling mechanical systems govern the continuous dynamics while discrete dynamics were handed by an impact model using impulse-like forces and balancing angular momentum. This combination of continuous and discrete dynamics motivated the use of hybrid systems for modeling purposes. The framework of hybrid systems was used to model three-dimensional bipedal walking in a general setup for a robotic model with a hip, knees, and feet with the goal of obtaining stable walking. To achieve three-dimensional walking, functional Routhian reduction was used to decouple the sagittal and coronal dynamics. By doing so, it was possible to achieve walking in the two-dimensional sagittal plane on the three-dimensional model, restricted to operate in the sagittal plane. Imposing this restriction resulted in a reduced-order model, referred to as the sagittally-restricted model. Sagittal control in the form of controlled symmetries and additional control strategies was used to achieve stable walking on the sagittally-restricted model. Functional Routhian reduction was then applied to the full-order system. The sagittal control developed on the reduced-order model was used with reduction to achieve walking in three dimensions in simulation. The control schemes described resulted in walking which was remarkably anthropomorphic in nature. This observation is surprising given the simplistic nature of the controllers used. Moreover, the two-dimensional and three-dimensional dynamics were completely decoupled inasmuch as the dynamic models governing the sagittal motion were equivalent. Additionally, the reduction resulted in swaying in the lateral plane. This motion, which is generally present in human walking, was unplanned and was a side-effect of the decoupling process. Despite the approximate nature of the reduction, the motion was still almost completely decoupled with respect to the sagittal and coronal planes.

No description available.

No description available.

Thesis (M.S.)--James Madison University, 2009. / Includes bibliographical references.

This thesis covers the study of an actively assisted passive walker with discontinuous and impulsive actuation. The dynamics of the passive and active portions are derived, and a comprehensive mathematical model is proposed. An actuation method is also proposed to study the use of multiple discrete actuation events in a walking gait. Two key cases are considered: actuation at the stance point and at the EA point of a non-kneed walker. An experimental walker was designed that is capable of passive walking and has an experimental implementation of the proposed actuation system. A thorough characterization of the model is then performed, with experimental validation to show that: at high ramp angles, energy injection results in an increase in BOA of ~38% on a stable walking gait at a Ct of 0.086, and at low ramp angles, injection results in a stride length increase of ~29% at a Ct of 0.06.

Objectives This thesis aimed to explore psychological factors associated with walking behaviour in patients with Peripheral Arterial Disease, within the framework of Leventhal et al’s (1998) Common-sense Model of Self-regulation of Health and Illness. The objective was to identify psychological factors which could be modified to increase walking behaviour in these patients. Method A series of three studies were conducted to achieve these aims. The first study was an exploratory qualitative study, to explore the illness and treatment beliefs and walking behaviour of patients with intermittent claudication. The second study was a cross-sectional postal questionnaire to a cohort of patients with intermittent claudication, which tested the influence of the psychological factors identified in the qualitative study, in a larger sample. The final study was a randomised controlled trial of a brief psychological intervention designed to modify the illness and walking beliefs of patients with intermittent claudication, in order to increase walking behaviour. Results Beliefs about intermittent claudication, and beliefs about walking were both found to be associated with walking behaviour in the qualitative study. The results from the cross-sectional postal questionnaire confirmed this relationship – taken as a set, illness and walking beliefs accurately predicted adherence to minimum walking levels for 93.4% of the sample. The brief psychological intervention successfully modified illness and treatment beliefs and increased walking behaviour in patients newly diagnosed with intermittent claudication. Conclusion This thesis highlights the importance of illness and walking beliefs to the walking behaviour of patients with intermittent claudication. The thesis has added to the body of knowledge about intermittent claudication, and the findings of this thesis have implications for the treatment of patients with intermittent claudication within the health service. Theoretical and clinical implications of this research are discussed.

Understanding the underlying coordination mechanisms that lead to a patient’s poor walking performance is critical in developing effective rehabilitation interventions. However, most common measures of rehabilitation effectiveness do not provide information regarding underlying coordination mechanisms. The overall goal of this research was to analyze the relationship between two potential measures of walking performance (step length asymmetry and module composition) and underlying walking mechanics. Experimental analyses were used to analyze the walking mechanics of hemiparetic subjects grouped by step length asymmetry. All groups had impaired plantarflexor function and the direction of asymmetry provided information regarding the compensatory mechanism used to overcome this plantarflexor impairment. Those subjects who walked with longer paretic than nonparetic steps compensated using increased output from the nonparetic leg, while those with symmetric steps compensated using a bilateral hip strategy. These results suggest that step length asymmetry may provide information regarding underlying coordination mechanisms that can be used to guide rehabilitation efforts. Another way to assess walking performance is to directly analyze deficits in muscle coordination. Recent studies have suggested that complex muscle activity during walking may be generated using a reduced neural control strategy organized around the co-excitation of multiple muscles, or modules, which may provide a useful framework for characterizing coordination deficits. Simulation analyses using modular control were performed to understand how modules contribute to important biomechanical functions of non-impaired walking and how the generation of these functions is altered in groups of post-stroke hemiparetic subjects who commonly merged different sets of non-impaired modules. The non-impaired simulation found that six modules are needed to generate the three-dimensional tasks of walking (support, forward propulsion, mediolateral balance control and leg swing control). When the plantarflexor module was merged with the module controlling the knee extensors and hip abductors, forward propulsion and ipsilateral leg swing were impaired. When the module controlling the hamstrings was merged with the module controlling the knee extensors and hip abductors, forward propulsion, body support and mediolateral balance control were impaired. These results suggest that module analysis may provide useful information regarding the source of walking deficits and can be used to guide rehabilitation efforts. / text

Diabetes affects 25.8 million Americans. Complications related to this growing disease impact public health. One secondary complication of diabetes is changes in skin that can contribute to an increased risk for ulceration. Skin of people with diabetes has not been characterized over time nor has the skin’s acute response to exercise been assessed. The objective of this project was to establish the changes in skin properties over time, within different ambient environments, and after acute exercise. This objective sought to address the central hypothesis that skin will demonstrate decreased stiffness and increased elasticity as a result of acute physical activity. Skin stiffness, compliance, and thickness measurements of the plantar foot were compared across time and environment. Skin stiffness and compliance were also compared before and after treadmill walking. First, three devices were validated. Accuracy of the StepWatch was validated for people using assistive devices. The tissue interrogation device (TID), a novel device that measures tangential skin stiffness, and the myotonometer, which measures skin compliance, were validated using elastomer phantoms. Both were found suitable to measure plantar skin properties. Second, skin properties of 16 persons with and without diabetes were measured over time and environmental condition. Skin was variable across subjects over time, but was stable within subjects over a month, supporting the use of a repeated measures approach to interventional study on the plantar skin in people with diabetes. Previous findings for general skin characteristics were supported including the tendency for persons with diabetes to have a thinner epidermis and a thicker dermis than persons without diabetes. Tangential skin stiffness was determined to be less stiff in people with diabetes when measured in a medial-lateral direction. People with diabetes had lower tissue compliance than those without. Skin properties varied across environmental condition, supporting the consideration of testing environment when evaluating skin. Finally, changes in skin properties were evaluated in 32 persons with diabetes before and after treadmill (TM) walking. Using the TID, skin stiffness (tangential) at the great toe of people with diabetes (663.705±4.796 N/m) and without (647.753±5.328 N/m) were different (p=0.040). Stiffness immediately following TM walking did not differ from pre-walking stiffness, but subsequent trials had increased stiffness. Similar, but not significant responses were noted at the first metatarsal head. Compliance using normal loading increased after walking with statistical differences lasting 30-60 minutes.