Numerical investigation of the impact of Kenenisa Bekele’s cooperative drafting strategy on its running power during the 2019 Berlin marathon

Polidori, Guillaume; Legrand, F.; Bogard, Fabien; Madaci, Farouk; Beaumont, Fabien

doi:10.1016/j.jbiomech.2020.109854

Cited by 27 publications

(57 citation statements)

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“…A final issue we wish to address is the 63% efficiency assumed by Polidori et al . (7) for converting aerodynamic power to metabolic power. That value comes from Cavagna & Kaneko (35) for the efficiency of performing mechanical work to lift the body center of mass during level running.…”

Section: Discussionmentioning

confidence: 99%

“…Polidori et al . (4) used CFD to calculate the air resistance acting on Kenenisa Bekele (the second fastest marathoner to date) running solo at 5.75 m/s. They determined a frontal area of 0.475 m 2 and used a C d of 0.812 and an air density of 1.219 kg/m 3 .…”

Section: Relative Increase In Metabolic Power Per % Bwmentioning

confidence: 99%

“…Drafting allows the designated athlete to run at a faster speed with the same sustainable metabolic power (2), and thereby enhances performance (3). Several recent studies have performed calculations and computer simulations regarding the aerodynamics and energetics of drafting (4, 5, 6, 7). Some relied on Pugh’s measurements of oxygen uptake in a single subject running in a wind tunnel on a treadmill, drafting behind another runner (8).…”

Section: Introductionmentioning

confidence: 99%

“…Polidori et al . (7) also used CFD and presented a value of 7.77 N for a similarly sized athlete, Kenenisa Bekele, running solo at 5.75 m/s. A force of 7 N is just over 1% of these runners’ body weights (see Electronic Supplementary Material Appendix S1 for details).…”

Section: Introductionmentioning

confidence: 99%

“…Thus, the corresponding values for mechanical power at 5.86 m/s are also very similar: 47.2 W for Hill (9), 38.6 W for Beves & Ferguson (4) and 44.7 W for Polidori et al . (7). However, because those three studies each used a different and dubious method of converting to metabolic power, they surmised that overcoming aerodynamic drag comprises 3% (9), 9-10% (4) and 2.8% (7) of the metabolic cost of running (see Electronic Supplementary Material Appendix S1 for details).…”

Section: Introductionmentioning

confidence: 99%

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The metabolic cost of overcoming air resistive forces in distance running

Kram

Hoogkamer

2021

Preprint

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We lack a mechanistic understanding of the relationship between aerodynamic drag forces and metabolic power during running. Further, the energetic and time savings possible from reducing aerodynamic drag (drafting) are still unclear due to the different methods previously assumed for converting from force reductions to metabolic power savings. Here, we quantified how small horizontal impeding forces (equivalent to aerodynamic forces) affect metabolic power and ground reaction forces over a range of velocities in competitive runners. In three sessions, 12 runners completed six 5-minute trials with 5 minutes of recovery in-between. We tested one velocity per session (12, 14 and 16 km/h), at three horizontal impeding force conditions (0, 4 and 8 N). On average, metabolic power increased by 6.13% per 1% body weight of horizontal impeding force but varied considerably between individuals. With greater horizontal impeding force, braking impulses decreased while propulsive impulses increased (p < 0.001). Across running velocities, the changes in braking and propulsive impulses with greater impeding force were correlated (r = -0.97; p < 0.001), but were not related to individual changes in metabolic power. We estimate that at ~2-hour marathon pace, overcoming air resistive force comprises 8.52% of the gross metabolic power on average.

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Section: Discussionmentioning

confidence: 99%

Section: Relative Increase In Metabolic Power Per % Bwmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The metabolic cost of overcoming air resistive forces in distance running

Kram

Hoogkamer

2021

Preprint

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In memory of Kelvin Kiptum: a reflection on his record-breaking marathon and the future outlook for a sub 2-h race from a drafting perspective

Fernandes,

Maldonado

2024

Eur J Appl Physiol

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Drafting is a common technique to reduce the drag experienced by elite runners on races, leading to better running efficiency and energy savings. The tactic has been successfully used in previous races where world records were set, especially by Eliud Kipchoge in the 2018 and 2022 editions of the Berlin marathon. In the 2023 edition of the Chicago Marathon, Kenyan runner Kelvin Kiptum broke the Marathon record after a 2:00:35 finish. This feat becomes even more impressive by the lack of use of drafting formations, despite the availability of two pacers for the majority of the race. In this study, the drag faced by Kiptum and his pacers during the race is calculated by means of computational fluid dynamics (CFD). The performance of each runner is evaluated from an energetic standpoint, and the analysis is extended to include more efficient drafting formations.Our results indicate that, by properly using the advantages of drafting, Kiptum could have finished the race at a staggering 1:57:34, a full three minutes better than his own record and 215 seconds better than the previous world record.

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