Intermittent claudication of vascular origin is mainly caused by problems with the arterial blood supply to the lower limbs and is due to ischaemia and hypoxia in the lower limbs. Therefore, the flexion and extension status of the lumbar spine is irrelevant to the degree of pain, which appears after walking a fixed distance and disappears after stopping walking, and worsens when cycling and climbing hills. Neurogenic intermittent claudication is commonly a problem of spinal stenosis, caused by compression of the nerves, with symptoms relatively pronounced when the spine is extended backwards or straight backed and relatively mild when bending forward. When climbing hills, the pain is often less severe going up (weight forward) than going down, and may not be noticeable when cycling. Furthermore, these patients walk irregular distances each time they experience painful symptoms.