Many of us can still clearly remember the images of Eliud Kipchoge – assisted by an ever-rotating group of pacemakers – as he flew along Vienna’s streets in 2019 to become the first person ever to run a marathon in under two hours. According to a recent study, the reduced slipstream shaved more than three minutes off the speedy Kenyan’s time. The study also showed that a different formation among the pacemakers could have even more potential.

5 pacemakers for Kipchoge

In cycling, the power of slipstreams and aerodynamics is well-known. In running, on the other hand, air resistance is often underestimated. Despite this, the best 5000-metre runners manage average speeds of 24 km/h, which is equivalent to a fast cycling pace. Even Eliud Kipchoge, during his record-breaking run in Vienna, achieved impressive results with an average speed of 21 km/h.

Prior to his record-breaking run in Vienna, the logical step was to consider how best to optimise the slipstream using pacemakers. Around 41 world-class athletes were involved in the record attempt, including the Ingebrigtsen brothers from Norway and Julien Wanders from Switzerland. The pacemakers maintained a clearly defined V-formation to create as much of a slipstream as possible for Kipchoge. Five runners took turns to form an arrow shape in front of Kipchoge, made up of three rows: the front two runners on the outside, the middle two slightly inset and one directly in front of Kipchoge (image).

Measurements in the wind tunnel

Massimo Marro, a mechanical engineer from the École Centrale de Lyon, wanted to precisely calculate how much time could effectively be saved by having pacemakers run in the optimum formation. Without further ado, he recreated the entire Vienna setting in the wind tunnel and took various measurements with 1/10 scale articulated runner manikins. He published his findings in the scientific journal “Proceedings of the royal Society A” (www.royalsocietypublishing.org).

The key results: The formation used in Vienna reduced Eliud Kipchoge's air resistance by around half which, based on the study findings, reduced the time by three minutes and 33 seconds. According to Marro and his team however, even more time could have been saved by using a different formation.  This would have involved two runners at the front, one in front of the other, then two next to each other followed by one runner directly in front of Kipchoge; according to the study this would have saved an additional 49 seconds.

Despite all these calculations, critical questions still arise: if you remove the slipstream, which accounts for three-and-a-half minutes alone, along with the rumoured 2-3 minute time saving thanks to the carbon super shoes plus the additional seconds due to all of the other optimisations (such as raised banking and lighting), elite runner Eliud Kipchoge would have “only” run a time of 2:07 seconds in Vienna, which is the same time as Viktor Röthlin during his Swiss record run without wind-breakers and super shoes...

This therefore shows that the pieces of a marathon puzzle can't be quantified all that easily and precisely. The 2-hour barrier will probably only be broken when enough pacemakers in the right formation optimise the slipstream for the potential record runner. Let's see what the Berlin Marathon brings.

Foto: IMAGO