Patterns of ambulatory activity in subjects with and without intermittent claudication

Purpose: This study compared the patterns of ambulatory activity in subjects with and without intermittent claudication. Methods: The study participants were 98 subjects limited by intermittent claudication and 129 controls who were matched for age, gender, and race. Subjects were assessed on their ambulatory activity patterns for 1 week with a small, lightweight step activity monitor attached to the ankle using elastic Velcro (Velcro Industries BV, Manchester, NH) straps above the lateral malleolus of the right leg. The step activity monitor recorded the number of strides taken on a minute-to-minute basis, the time spent ambulating, and the time and number of strides measured at low (<15 strides/min), medium (15 to 30 strides/min), and high (>30 strides/min) cadences. Results: Subjects with intermittent claudication took fewer total strides each day than the controls (3149 ± 1557 strides/d vs 4230 ± 1708 strides/d; P < .001) and fewer strides at medium (1228 ± 660 strides/day vs 1638 ± 724 strides/day; P = .001) and high (766 ± 753 strides/day vs 1285 ± 1029 strides/day; P < .001) cadences. Subjects with intermittent claudication also had a lower daily average cadence than the controls (11.8 ± 2.9 strides/min vs 13.5 ± 3.1 strides/min; P < .001) and spent less total time ambulating each day (264 ± 109 min/day vs 312 ± 96 min/day; P = .034), primarily at medium (58 ± 30 min/day vs 75 ± 32 min/day; P < .001) and at high (19 ± 17 min/day vs 30 ± 22 min/day; P = .001) cadences. Conclusion: Intermittent claudication is associated with lower total daily ambulatory activity owing both to less time ambulating and to fewer strides taken while ambulating, particularly at moderate and high cadences.