Why Athletes do not Negative Split Some Endurance Events: A Thermodynamics-Based Explanation

Abstract

The study expands upon a thermodynamics-based model that considers the work associated with gas pressure, volume and temperature changes for the glucose-based equation of respiration to accurately predict the slow component of oxygen uptake kinetics [1]. The extended model, when applied to physiological data for endurance events, further supports model efficacy by its prediction of maximum velocities in swimming and quantitative explanation of observed race splitting strategies. The model suggests that athletes often effectively negative split an endurance race, even when recorded times indicate that an even or positive split strategy has been employed. Viz., athletes often essentially maintain constant maximal steady-state effort for which constant oxygen consumption leads to a gradual decrease in velocity due to an unavoidable loss of efficiency as calculated by the model. Any final stage surge then results in an "effective" negative spilt since effort prior to the surge is approximately constant.