Aim of my PhD
This thesis investigated the reliability, measurement, determinants, acute changes, and chronic adaptability of running economy (RE) during prolonged running and compared temporal changes (ie, durability1) between physiological determinants of endurance performance in well-trained male runners. It was hypothesised that RE durability would vary between athletes according to performance level and running training characteristics, that strength training would enhance RE and fatigued performance and that durability would differ between physiological determinants.
Rationale of my PhD
According to the classical model of endurance running performance,2 speed is determined by three physiological parameters: maximal oxygen uptake (V̇O₂max), the fractional utilisation of V̇O₂max at lactate threshold (FULT) and RE. However, the model does not account for alterations of physiological determinants due to accumulated fatigue during prolonged exercise, as recently highlighted.3 The capacity to mitigate acute declines in such determinants has been recently proposed as a distinct parameter influencing endurance performance,1 3 typically referred to as durability.
RE is defined as the metabolic cost of covering a given distance and directly impacts performance, with more economical runners achieving faster speeds for the same cost. Numerous studies have assessed changes in RE during prolonged running (ie, RE durability), finding a wide range of deterioration (1%–26%). An investigation of factors influencing RE durability is warranted to explore these differences. In an unfatigued state, RE depends on factors such as measurement unit (energy cost (EC) vs oxygen cost (OC)) …

