Arm cranking is a useful alternative exercise modality for improving walking performance in patients with intermittent claudication; however, the mechanisms of such an improvement are poorly understood. The main aim of the present study was to investigate the effects of arm-crank exercise training on lower-limb O 2 delivery in patients with intermittent claudication. A total of 57 patients with intermittent claudication (age, 70 + − 8 years; mean + − S.D.) were randomized to an arm-crank exercise group or a non-exercise control group. The exercise group trained twice weekly for 12 weeks. At baseline and 12 weeks, patients completed incremental tests to maximum exercise tolerance on both an arm-crank ergometer and a treadmill. Respiratory variables were measured breath-by-breath to determine peakVO 2 (O 2 uptake) and ventilatory threshold. Near-IR spectroscopy was used in the treadmill test to determine changes in calf muscle StO 2 (tissue O 2 saturation). Patients also completed a square-wave treadmill-walking protocol to determineVO 2 kinetics. A total of 51 patients completed the study. In the exercise group, higher maximum walking distances (from 496 + − 250 to 661 + − 324 m) and peakVO 2 values (from 17.2 + − 2.7 to 18.2 + − 3.4 ml · kg − 1 of body mass · min − 1 ) were recorded in the incremental treadmill test (P < 0.05). After training, there was also an increase in time to minimum StO 2 (from 268 + − 305 s to 410 + − 366 s), a speeding ofVO 2 kinetics (from 44.7 + − 10.4 to 41.3 + − 14.4 s) and an increase in submaximal StO 2 during treadmill walking (P < 0.05). There were no significant changes in the control group. The results suggest that the improvement in walking performance after arm-crank exercise training in patients with intermittent claudication is attributable, at least in part, to improved lower-limb O 2 delivery
