Depletion Of D' In The CS/D' Model Explains "dropping Off" From The Leading Pack In Elite Runners

Abstract

During distance races, lesser runners typically “drop off” from the leaders as the race progresses. It is expected that this drop off is attributable to progressive homeostatic disturbances that make continuing with the leading pack intolerable. This homeostatic disturbance can be represented by depletion of D’ within the Critical Speed/D’ model. However, this assumption has not been quantitatively tested. Purpose: This study compares the point during the 2008 Olympic men’s 10 km (n = 36) when runners dropped off the leading pace versus the loss of D’, based on the differential D’ balance approach. Methods: Individual 100 m velocities were computed from the race protocol, and departures from the leading pace identified from rolling 400 m velocity plots. The D’ remaining, (%starting D’) was compared with the distance where the pace departed from that of the leaders. Results: Individual patterns were observed, for contenders (C) with leader @ 400 m remaining (n = 7)(CS = 6.13 ± 0.08 m/s, D’start 195 ± 63 m) vs non-contenders (NC) (n = 29) (CS = 5.94 ± 0.09 m/s, D’start = 202 ± 53 m). C hit minimal D’ at the end of the race(14 ± 48 m or 7 ± 23%), NC hit minimal D’ near the point of drop off (46 ± 29%)), and often increased D’ by the end of the race (54 ± 30%). Conclusions: Depletion of D’ from running >CS early in the race appears to explain dropping off from the leading pack in elite 10 km races in NC. NC typically increase D’ from drop off to end. Individual patterns of D’ depletion and the magnitude of D’end is rather variable.