TO THE EDITOR: While the viewpoint (3) superbly summarizes key factors underlining marathon running physiology and potential reasons for recent records surge, the inherently dynamic physiological nature of marathon running might have been understated. To comprehensively interpret marathon performance, one also needs to consider the time-dependent physiological alterations during both, the actual marathon run and the preceding training. In particular, the average elite marathon running velocities can be explained by regression calculations using “static” values of maximal oxygen uptake, lactate threshold (LT) and running economy (RE) (2). However, given the dynamic nature of long-distance running, the contribution of these determinants to subsequent physiological responses and actual running performance significantly varies and cannot be precisely predicted by static values modeling. The variation can relate to both, the relative contribution/importance of each factor and the duration-related dynamic differences. Indeed, LT can be altered due to potential glycogen-depletion related reduction in lactate production while RE is known to decrease as a function of running duration (4). Training also represents a complex dynamical system comprised of numerous fluctuating determinants (i.e. intensity/duration/frequency, hypoxic/heat training, tapering) further complicated by the distinct individual (5) and daily (1) variability in training-induced responses. It, thus, seems crucial to constantly monitor the corresponding training-related physiological fluctuations. Given our currently scarce understanding, further exploration of time-dependent dynamics of physiological determinants during both, the marathon running and training seems warranted. It will provide important insight into the often omitted “dynamic” aspect of the marathon performance puzzle and, ultimately, limits of marathon running.
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4. Lazzer S, Salvadego D, Rejc E, Buglione A, Antonutto G, and di Prampero PE. The energetics of ultra-endurance running. Eur J Appl Physiol 112: 1709-1715, 2012.
5. Ross R, Goodpaster BH, Koch LG, Sarzynski MA, Kohrt WM, Johannsen NM, Skinner JS, Castro A, Irving BA, Noland RC, Sparks LM, Spielmann G, Day AG, Pitsch W, Hopkins WG, and Bouchard C. Precision exercise medicine: understanding exercise response variability. Br J Sports Med 53: 1141-1153, 2019.