The beneficial effects of exercise training as a treatment have been confirmed in several randomised controlled trials. The optimum form of exercise still hasn't been elucidated. The mechanisms of improvement of claudication with exercise are largely unknown. Although exercise stimulates an ischaemic-reperfusion (I-R) insult, repetitive exercise may produce an adaptive response to this I-R insult. Other potential themes include effect of exercise on stimulating or inhibiting angiogenesis and/or muscle protein synthesis.