This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. This study is identical to SPID #0050 but this study is funded. Peripheral arterial disease (PAD) is a leading cause of morbidity due to ambulatory limitations associated with intermittent claudication. Intermittent claudication is ischemic muscular pain that occurs in the calf, thigh, or buttock muscle groups during ambulation when the pace exceeds the capacity of the peripheral circulation to adequately perfuse the active lower extremity musculature. Intermittent claudication afflicts 5% of the US population older than 55 years of age, thereby limiting daily physical activities and negatively affecting quality of life in many older adults. Because ambulation is one of the primary physical activities performed by the elderly, it is not surprising that PAD subjects adopt a sedentary lifestyle and typically cluster around the extreme low end of the physical activity spectrum. The ambulatory dysfunction and sedentary lifestyle in subjects with PAD may trigger a decline in other domains of physical function. For example, PAD subjects have reduced strength in the lower extremities, impaired balance and higher prevalence of falling, altered gait even before claudication pain occurs, worse self-perceived ambulatory function, and lower health-related quality of life than non-PAD controls. Consequently, PAD subjects have difficulty completing activities of daily living that utilize the lower extremities, while some subjects are unable to perform these tasks altogether. A primary therapeutic goal for PAD patients with intermittent claudication is to regain lost physical function through exercise rehabilitation. Medically supervised exercise programs have been studied extensively over the past 35 years, and are efficacious in the clinical management of intermittent claudication. Specifically, supervised exercise rehabilitation improves initial claudication distance (ICD) and absolute claudication distance (ACD) during a standarized treadmill test, as well as overground ambulatory function, perceived ambulatory function, physical activity level, quality of life, and calf blood flow in PAD patients with intermittent claudication. Consequently, exercise-mediated improvement in claudication pain is a triggering event that breaks the downward spiraling chain of events in physical function in PAD patients. Ambulatory dysfunction secondary to intermittent claudication is the initial step in a downward spiral of physical function in older patients with PAD. The overall hypothesis of this project is that a home-based exercise program utilizing new physical activity monitoring technology that quantifies the volume and intensity of walking will be as equally efficacious as a standard hospital-based supervised exercise program and better than usual care control in improving ambulation, physical function, vascular function, and health-related quality of life through the physiologic mechanisms of improved walking economy, calf muscle circulation, and calf muscle oxygenation. This hypothesis will be tested in a prospective, randomized controlled clinical trial that compares a home-based exercise group, a hospital-based exercise group, and a delayed-entry, non-exercise group
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