Function Of Walking Speed Research Articles

Polar bear locomotion: body temperature and energetic cost

The metabolic response of a 190-kg polar bear was tested at four different walking speeds within a respiration chamber mounted on a treadmill. Regressions of deep body temperature and oxygen consumption as a function of walking speed were determined. Equilibrium deep body temperature increased exponentially with speed of locomotion and indicated a relative inability to dissipate metabolic heat at high walking speeds. Metabolic rate, as measured by weight-specific oxygen consumption, was also best fit by a curvilinear equation and was twice that predicted by a general equation for quadruped locomotion. The apparent inefficiency of locomotion in polar bears suggests a compromise between thermoregulation, hunting strategies, and economy of transport.

Predicting metabolic cost of level walking.

Energy expenditure in walking is usually expressed as a function of walking speed. However, this relationship applies only to freely adopted step length-step rate patterns. Both the step length and the step rate must be used to preduct the energy expenditure for any combination of step length and step rate. Evidence on seven subjects indicates that the energy demand for such a combination can be determined by conducting two experiments. In the first, the subject is allowed to freely choose his own walking pattern to achieve a set of prescribed speeds. In the second, the speed is kept constant but the subject is forced to adopt a range of prescribed step rates. The results of the two experiments combined yield enough data to make possible the determination of the energy equation of the pattern, encompassing both "free" and "forced" gaits. Results show that the freely chosen step rate requires the least oxygen consumption at any given speed. Any other forced step rate at the same speed increases the oxygen cost over that required for the "free" step rate.

An equation for prediction of energy expenditure of walking and running.

An equation for prediction of energy expenditure of walking and running.

Energy cost of loads carried on the head, hands, or feet.

Energy cost of loads carried on the head, hands, or feet.