 Experimental Design The project is a pilot study that is both cross-sectional and longitudinal in nature. The initial baseline measurement sessions will allow comparisons of acute perfusion and metabolic physiologic responses between two groups of subjects with and without PAD. Duplicate testing for each subject will allow assessment of the test-retest reliability of the measurements. The PAD subjects perfusion and metabolic responses will be assessed again after three months of exercise training walking and calf muscle exercise. While not a definitive clinical trial of the exercise training intervention, the results should provide estimates of sample and effect sizes to design a more definitive future clinical trial. 