A trade-off is inevitable between the enormous anaerobic capacity needed to surge over the final laps of a track race, which Farah had in sprinting to Olympic gold medals, and the aerobic endurance required to maintain a steady, blistering pace over a marathon, said Andrew Jones, an exercise physiologist at the University of Exeter in England who has studied the performances of Farah and Kipchoge.
Simply put, said Alex Hutchinson, a columnist for Outside Magazine and the author of “Endure: Mind, Body and the Curiously Elastic Limits of Human Performance,” Farah’s problem “isn’t that he’s not good at longer distances; it’s that he’s too good at shorter distances.”
Compared with Farah, Kipchoge has superior “critical speed,” or the maximum aerobic speed that can be sustained, Jones said, which would be a significant advantage over 26.2 miles. Kipchoge might also have more sustainable running economy, the amount of oxygen required to run at a given speed, Jones said, which would lessen his fatigue later in a marathon.
Farah’s bounding, loping gait contrasts with the flowing, metronomic style of classic marathon running and is “probably a little more energy expending,” said Amby Burfoot, the winner of the 1968 Boston Marathon and a longtime editor at Runner’s World magazine.
There are also fewer opportunities for runners to experiment with their strategy and tactics in the marathon compared with their ability to do so while racing on the track. While runners could race once a week at the peak of their season on the track, elite marathoners usually run only two marathons a year, and there are a finite number of top races even in the fastest legs (though Kipchoge is challenging that notion). A lot can go wrong over two hours.
Experts who were interviewed wondered whether Farah had difficulty fueling during a marathon, which is not required at shorter distances. Or whether he had the patience for a 26.2-mile grind. Or if he could muster the same motivation after such a brilliant career on the track.