A novel footwear intervention to assist in the gait of patients with intermittent claudication
Peripheral arterial disease is characterised by blocking of the peripheral arteries. A common symptom is intermittent claudication, a cramping pain felt intermittently during activity such as walking. This is due to muscle oxygen demand surpassing the available supply and can significantly reduce mobility and quality of life. One noninvasive treatment option is the use of footwear and orthoses to alter muscle activity and delay the onset of calf pain. The aim of the research in this thesis was to determine the gait characteristics of individuals with intermittent claudication and to assess the effects of footwear and orthotic interventions on their gait. Three studies were completed. The first compared gait of individuals with intermittent claudication to that of healthy age-matched controls. The second assessed the effectiveness of three rocker soled shoes (with and without an anklefoot orthosis) in altering lower limb kinetics and muscle activity. The third investigated the effectiveness of the most effective rocker soled shoe intervention (in study two) in increasing mobility during gait and in real world situations. People with intermittent claudication adopt a slower walking speed and shorter step length and have reduced internal ankle moment and ankle power production during push-off phase of gait. The peak EMG activity of their soleus muscle also appears to be lower than healthy counterparts. A rocker soled shoe, consisting of three curves blended into one, was found to be the most effective at decreasing the moment, power and muscle activity demand at the ankle during the gait of individuals with intermittent claudication. The findings indicated the potential ability of the shoe to reduce the oxygen demand of the calf, such that it might delay onset of intermittent claudication pain. However, when tested under real world conditions this rocker soled shoe did not significantly delay the onset of pain in people with intermittent claudication during over ground gait, or increase maximum walking distance. Further modifications to the rocker soled design will be required to further reduce oxygen required by the lower limb muscles before a clinically significant delay in intermittent claudication pain can be achieved.
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