Time in human endurance models - From empirical models to physiological models

This article traces the study of interrelationships between power output, w ork done, velocity maintained or distance covered and the endurance time ta ken to achieve that objective. During the first half of the twentieth centu ry, scientists examined world running records for distances from <100m to > 1000km. Such examinations were empirical in nature, involving mainly graphi cal and crude curve-fitting techniques. These and later studies developed t he use of distance/time or power/time models and attempted to use the param eters of these models to characterise the endurance capabilities of athlete s. More recently, physiologists have proposed theoretical models based on t he bioenergetic characteristics of humans (i.e. maximal power, maximal aero bic and anaerobic capacity and the control dynamics of the system). These m odels have become increasingly complex but they do not provide sound physio logical and mathematical descriptions of the human bioenergetic system and its observed performance ability. Finally, we are able to propose new param eters that can be integrated into the modelling of the power/time relations hip to explain the variability in endurance time limit at the same relative exercise power (e.g. 100% maximal oxygen uptake).