World longdistance running elite: ethnicityspecific run energy efficiency analysis
ˑ:
Dr.Hab. V.D. Kryazhev^{1}
Dr. Hab., Professor V.Y. Karpov^{2}
PhD, Professor K.K. Skorosov^{3}
PhD, Associate Professor V.I. Sharagin^{4}
^{1}Federal Scientific Center for Physical Culture and Sports, Moscow
^{2}Russian State Social University, Moscow
^{3}Penza State University, Penza
^{4}Moscow State University of Psychology and Education, Moscow
Corresponding author: kryzev@mail.ru
Keywords: longdistance running, mathematical modeling, run energy cost, run energy efficiency.
Background. Di Prampero (Italy) [4] and F. Peronne, G. Thibault (Canada) [7] have developed a middle/ longdistance run energy cost rating method based on the aerobic/ anaerobic metabolism capacity and kinetics rating formulae, with the resulting values calculated with only 0.68% error. Their calculations of VO2max were only 23 mm/kg/min different from the published individual longdistance running elite test data. It is commonly assumed that the longdistance running elite energy cost varies at around 3.86 J/kg/m, and the maximal oxygen consumption at 80 ml/kg/min [7]. Later it was found, however, that the East African longdistance running elite (from Ethiopia, Kenya and other nations) runs in much more energy efficient manner that the Europeans [5, 6]. We believe that it may be pertinent in this context to have the common longdistance running energy efficiency analysis and findings revised.
Objective of the study was to analyze, on a mathematical and statistical basis, the African and European longdistance running elite energy efficiency.
Methods and structure of the study. We collected for analysis the individual competitive performance data of the topfive European and topfive African runners from the 2019 top100 list: see Table 1.
Table 1. Individual competitive performance data of the topfive European and topfive African competitors in 3000m, 5000m and 10000m

Athlete 
Nation 
Rank 
3000m 
5000m 
10000m 
1 
T. Bekele 
ETH 
15000 
7:32.55 
12:52.98 

2 
S. Barega 
ETH 
15000 
7:32.17 
12:43.02 
26:49.46 
3 
H. Gebhriwet 
ETH 
110000 
7:30.36 
12:45.82 
26:48.95 
4 
A. Hadis 
ETH 
310000 
7:39.10 
12:56.27 
26:56.46 
5 
J. Cheptegey 
UGA 
110000 
7: 33.26 
12:57.41 
26:38.36 
6 
R. Ringer 
GER 
1110000 
7:53.81 
13:23.04 
28:44.17 
7 
J. Wanders 
SWI 
155000 
7:43.62 
13:13.84 
27:17.29 
8 
S. McSweyn 
AUS 
710000 
7:34.79 
13:05.23 
27:23.20 
9 
S.N. Moen 
NOR 
2710000 
7:52.55 
13:20.16 
27:24.78 
10 
P. Tiernan 
AUS 
125000 
7:37.76 
13:12.68 
27:29.40 
Sports results (LnT times) were converted into mean distance speed (V) and processed in Excel to produce VLnT correlations. The critical running speed (Vcrit) was found based on the seventhminute LnT (Ln 420 = 6.04) [7, 8]. Based on the critical running speed concept [1] and using the ∆MAP = Crtot ∙ Vcrit, W ratio, we computed the maximum aerobic power (MAP) above the quiescent level (∆MAP) using the equation VO2max = (∆MAP + 1.2) ∙ 2.87 ml/kg/min. Note that Crtot means the run energy cost net of the air resistance. Run energy efficiency (net energy cost Cr) was estimated at 3.76 J/kg/m for the Europeans and 3.30 J/kg/m for the Ethiopians [4, 5]. Note that the aerobic maximum aerobic power, run energy cost and endurance ratio (E, rated by the regression curve tilt angle V  LnT [8] as provided by PéronnetThibault model [7]) may be used to compute the individual energy efficiency [2].
Results and discussion. Given on Figure hereunder are the regression equations for the African and European runners with virtually the same tilt angles indicative of the similar E ratios and endurance indices EI. The critical speeds generated by the regression equations show advantage of the African group. Thus the Ethiopian runners demonstrate higher energy efficiencies i.e. energy costs per meter net of the air resistance; and, hence, lower metabolic demand (MD) on the distances. It should be emphasized that the African runners are generally more successful than the Europeans in spite of the lower aerobic maximums. The mathematical models that we applied give fairly accurate energy efficiency rates based on the known energy costs [2, 7].
Figure 1. Elite longdistance runners’ distance speed variations on three distances
Note that the mean values for the European/ African longdistance running elites vary within the range of around 7% [4, 6], although the intergroup energy efficiencies are quite significant.
Table 2. Calculated energy cost and performance test data of the European and African elite longdistance runners on 3000m distance
Elite longdistance runners 
V, m/s 
Pv, W/kg 
VO2max, ml/kg/m 
Vcrit, m/s 
Cr, J/kg/m 
Africans 
6,12 ±0,01 
26.76 ±0.03 
76.2 ±0.11 
6.65 ±0.011 
3.80 ±0.006 
Europeans 
6,14 ±0,013 
28.62 ±0.06 
82.4 ±0.17 
6.51 ±0.014 
4.21 ±0.009 
Note: р≤0.05; V – running speed; Pv – metabolic demand; VO2max – maximum oxygen consumption; Vcrit – critical running speed; Cr – energy cost per meter net of air resistance
The high run energy efficiencies of the world leading Ethiopian and Kenyan middle and longdistance runners may be due to the genetically predetermined lower limb metrics and habitual highaltitude living conditions [3] that develop more energy efficient aerobic metabolism. The shorter shin circumference (minus 3 cm on average) secures more efficient massinertial performance of the distal leg segments and eases the mechanical work [6]; plus the lower shoulder of forces acting in the Achilles tendon contributes to the energy efficiency of the elastic elements in the musculoskeletal system [3].
Conclusion. Mathematical analysis of the competitive performance data and energy efficiency of elite longdistance runners demonstrated serious advantages of the East African runners over their European competitors secured by the lower metabolic demands on the distances and, hence, better energy efficiencies as a sound basis for their great competitive accomplishments despite the relatively lower aerobic maximums.
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