Some studies have investigated the difference in histochemical and biochemical characteristics of skeletal muscle between patients with PAD and healthy age-matched subjects. Most of the studies into muscle biopsy from patients with PAD have demonstrated alterations in muscle fibre type distribution, denervation and alterations in muscle metabolism with no insight into protein expression12, 13, 14. There is considerable evidence that the metabolic status of skeletal muscle is perturbed in patients with PAD as compared with age-matched healthy controls. Amongst the earliest observations was the unexpected finding that the expression and activity of several mitochondrial enzymes are increased in skeletal muscle from limbs with PAD. The skeletal muscles in patients with IC, do change with exercise but the current evidence does not shed light on the mechanisms of change or if the change is the same in all patients. We do already know that some patients improve with exercise while others do not. A question thus arises as to whether there exists a bio-diversity in these patients' response to exercise.