Energetics of running in top-level marathon runners from Kenya.

On ten top-level Kenyan marathon runners (KA) plus nine European controls (EC, equivalent to KA), we measured maximal oxygen consumption (VO2max) and the energy cost of running (Cr) on track during training camps at moderate altitude, to better understand the KA dominance in the marathon. At each incremental running speed, steady-state oxygen consumption (VO2) was measured by telemetric metabolic cart, and lactate by electro-enzymatic method. The speed requiring VO2 = VO2max provided the maximal aerobic velocity (νmax). The energy cost of running was calculated by dividing net VO2 by the corresponding speed. The speed at lactate threshold (ν(ΘAN)) was computed from individual Lâ(b) versus speed curves. The sustainable VO2max fraction (Fd) at ν(ΘAN) (F(ΘAN)) was computed dividing nu(ΘAN) by νmax. The Fd for the marathon (Fmar) was determined as Fmar = 0.92 F(ΘAN). Overall, VO2max (64.9 ± 5.8 vs. 63.9 ± 3.7 ml kg(-1) min(-1)), νmax (5.55 ± 0.30 vs. 5.41 ± 0.29 m s(-1)) and Cr (3.64 ± 0.28 vs. 3.63 ± 0.31 J kg(-1) m(-1)) resulted the same in KA as in EC. In both groups, Cr increased linearly with the square of speed. F(ΘAN) was 0.896 ± 0.054 in KA and 0.909 ± 0.068 in EC; Fmar was 0.825 ± 0.050 in KA and 0.836 ± 0.062 in EC (NS). Accounting for altitude, running speed predictions from present data are close to actual running performances, if F(ΘAN) instead of Fmar is taken as index of Fd. In conclusion, both KA and EC did not have a very high VO2max, but had extremely high Fd, and low Cr, equal between them. The dominance of KA over EC cannot be explained on energetic grounds.

Is it time to consider a new performance classification for high-level male marathon runners?

La Torre, A, Vernillo, G, Agnello, L, Berardelli, C, and Rampinini, E. Is it time to consider a new performance classification for high-level male marathon runners? J Strength Cond Res 25(12): 3242-3247, 2011-Studies have attempted to describe human running performances by the analysis of world-record times. However, to date, no study has analyzed the evolution of high-level marathon performances over time. Thus, the purpose of this study was to analyze these performances across the past 42 years with the aim of delineating a time-based classification. To identify the nature of the phenomenon represented by the sequence of observations, we examined the data collected (i.e., 8,400 times from 1969 to 2010) as a time series. The leading time (LT) and the mean 200 times (T200) per year underwent a nonlinear but significant decrement (r = -0.92, p < 0.001 and r = -0.98, p < 0.001, respectively). In fact, from 1969 to 2010, the mean time differences were 3 minutes 20 seconds ± 1 minute 59 seconds and 7 minutes 1 second ± 2 minutes 48 seconds, corresponding to an improvement of 5 and 10 seconds per year for LT and T200, respectively. Furthermore, trend analysis suggested a disruption in marathon time improvements, indicating the presence of 3 points in the time series in which the performance significantly improved with respect to that of the previous years, corresponding to the years 1983-1984 (p < 0.001), 1997-1998 (p < 0.003), and 2003 (p < 0.001). In conclusion, despite the trend in high-level marathon performances being better explained by a nonlinear tendency, significant improvements in the ability of the high-level marathon runners to complete the distance were observed. These improvements are likely to be related to sociological, environmental, physiological, and training-method factors. Researchers and coaches should take into account these enhancements by using the time classification proposed in this study to better reflect the marathon performance profile of their athletes.