Peripheral arterial occlusive disease (PAOD) often presents as intermittent claudication, which may be caused by impaired vasodilation. Impairment of resistance vessels may contribute to the pathogenesis of PAOD, and explain the poor correlation between resting blood flow and limb function. Collateral function following arterial occlusion is not well defined, however collaterals and arterialized collateral capillaries (ACCs) in male and female animal models exhibit impaired vasodilation following arterial occlusion, which can potentially be improved with exercise training. Furthermore, resistance vessels in the ischemic tree and stem are likely involved in the pathogenesis of PAOD, however the relative importance of each is unknown. Therefore, we measured functional vasodilation in pre-existing collaterals, ACCs, the ischemic tree, and the stem region, 7 and 21-days following spinotrapezius feed artery ligation in male and female BALB/c mice, and with exercise therapy. Vasodilation in ACCs was more impaired in female mice than in males. Generally, vasodilation was impaired at day-7, likely due to impaired endothelium-dependent and smooth muscle-dependent vasodilation in maturing collaterals, and recovered by day-21. Exercise training appears to enhance collateral reactivity, more in ACCs in males than in females, suggesting that its therapeutic benefits are linked not only to structural adaptation but also to vessel functionality. Therefore, future research is required to determine the cause of sex differences in exercise therapy to treat peripheral arterial occlusive disease.