ENERGY-COST OF AMBULATION WITH DIFFERENT METHODS OF FOOT AND ANKLE IMMOBILIZATION

In order to measure the energy cost of immobilization of the foot and ankle during ambulation, 14 healthy male volunteers exercised while we aring various immobilization devices. Oxygen consumption, oxygen cost, cardiac output, minute ventilation, heart rate, stroke volume, stride length, and stride frequency were determined at a steady state of exe rcise as the subjects walked on a treadmill at 80 m/min (equivalent to the comfortable walking speed of approximately 3 mi/h). Each subject was tested with three different types of immobilization devices: a sho rt leg walking cast, a prefabricated lower leg orthosis, and a rigid-s oled surgical shoe. The results were compared with those for the same men ambulating without an immobilization device. Ambulation with the s hort leg walking cast and the prefabricated lower leg orthosis require d significantly more energy in comparison with control values (all p v alues < 0.006) in terms of oxygen cost, cardiac index, oxygen consumpt ion, and minute ventilation. However, when the rigid-soled surgical sh oe was worn, energy consumption as measured by all parameters was not significantly increased compared with control values. Comparison of th e findings for the short leg walking cast and the prefabricated lower leg orthosis showed no significant differences in any parameter of ene rgy consumption. Stride length, however, was significantly shorter in the short leg walking cast compared with all immobilizers tested.