This prospective , randomized , controlled clinical trial compared changes in primary outcome measures of claudication onset time ( COT ) and peak walking time ( PWT ) , and secondary outcomes of submaximal exercise performance , daily ambulatory activity , vascular function , inflammation , and calf muscle hemoglobin oxygen saturation ( StO2 ) in patients with symptomatic peripheral artery disease ( PAD ) following new exercise training using a step watch ( NEXT Step ) home-exercise program , a supervised exercise program , and an attention-control group .