Walking at moderate speed with heel-less shoes increases calf blood flow

This study was designed to examine the physiological and biochemical effects of wearing heel-less shoes over a wide range of walking speeds. Six male students wearing alternately regular shoes and heel-less shoes walked at the constant speeds of 60, 80, 100 and 120 m/min for 10 min on a treadmill at 0% grade. The average heart rate was higher during heel-less shoe trials than when subjects walked in regular shoes at each speed, but differences were not significant. The calf blood flow showed its highest mean value at 80 m/min when subjects walked in heel-less shoes, and at 100 m/min when they walked in regular shoes. However, at walking speeds higher than these, calf blood flow decreased for wearers of both types of shoes. The calf blood flow after 80 m/min was higher when walking in heel-less rather than regular shoes. Blood lactate concentration after walking in heel-less shoes at 120 m/min was significantly higher than basal level, but after walking in regular shoes it was unchanged from the level before walking. Noradrenaline concentration at 120 m/min while walking in heel-less shoes was significantly higher than while walking in regular shoes. In conclusion, walking exercise in heel-less shoes induced an increase of the calf blood flow at a moderate speed, and increased glycogen metabolism and noradrenaline secretion at a faster speed.