This week a unique paper was published in the Journal of Applied Physiology. Professor Andrew Jones and his team (1) reported on the physiology of 16 elite male distance runners including Eliod Kipchoge, the only person to have run under 2h for the marathon. In the paper they report the physiological variables measured during Nike’s Breaking 2 project. The average half marathon time of the group of runners studied was 59:53 and the average marathon time was 2:06:53 and thus these are truly elite and truly unique data. The data give us great insights into what it takes to run sub 2 hours for a marathon.
Physiology of the elite marathon runner
To run a fast marathon the following characteristics of a runner are important:
A high VO2max
The ability to sustain a high percentage of VO2max for a long time
A high lactate threshold or critical speed
A very low oxygen cost of running (high running economy)
Below we will discuss these in more detail but there are of course other variables that influence the runners’ performance and in order to run this fast, all other conditions must be optimised. Some of these factors are external, like altitude and weather conditions. Other factors, like nutrition, can be controlled. We will discuss nutrition separately in a future blog. Of course, the role of footwear has been discussed extensively in the media already.
Maximal oxygen uptake
In terms of physiology, VO2max has been recognised as important for a long time. The more oxygen you can use the more energy you can produce for muscle contraction. There are many factors that influence how much oxygen you deliver to the muscle and use in the muscle. But there are two things of interesting in the data presented in the paper: the average peak VO2 was 71 ml/kg of these runners. This value is high but much higher values have been reported in the literature (values well over 80 ml/kg). There were also large differences in VO2max in this study between the runners and therefore I would conclude that VO2max may be important, but it certainly doesn’t tell the whole story.
Running economy
The oxygen cost of running or running economy (also sometimes referred to as efficiency) is a less common variable, but is maybe one of the most important variables. Oxygen cost refers to the amount of oxygen it takes to run at a certain speed. If a runner can run at the same speed, but uses less oxygen, he or she is more economical (or more efficient). An elite runner will have a lower oxygen cost, and essentially waste less oxygen on non-essential movement (movement that does not propel you forwards). The fact that these runners have very low vertical oscillation (4 cm) means that most power produced (and oxygen used) is used for forward motion and not wasted on motion upwards. The oxygen cost reported in the paper was 191 ml per kilogram bodyweight per kilometer. Many years ago I measured running economy with Haile Gebrselassie before his world record attempts and this was very similar (188 ml/kg/km). There are suggestions that the small lower legs (calves) of these runners result in better running economy, and although this will undoubtedly contribute, it is unlikely the whole explanation.
An elite runner will have a lower oxygen cost, and essentially waste less oxygen on non-essential movement
A high lactate turn-point or critical speed
These markers refer to the speed that can be maintained for a long time. Above this speed no steady state can be achieved and fatigue will develop exponentially. This will also allow runners to run at a higher percentage of their VO2max. On average, the lactate turnpoint was at 92%VO2max. This is very high for any standard. With the help of the average value obtained for the oxygen cost of running it is possible to predict that in order to run a marathon in 2h a 59kg runner needs to run at a VO2 of 67 ml/kg/min or 4.0L/min.
With the help of the average value obtained for the oxygen cost of running it is possible to predict that in order to run a marathon in 2h a 59kg runner needs to run at a VO2 of 67 ml/kg/min or 4.0L/min.
What is interesting is that the oxygen cost of running plays a very important role and this is something we can influence with nutrition. If we force the body to use more fat this will result in a higher oxygen cost, if we force it to use more carbohydrate we can lower the oxygen cost. In the next blog we will discuss why lighter runners may have a nutrition advantage.
References
Jones AM, Kirby BS, Clark IE, Rice HM, Fulkerson E, Wylie LJ, Wilkerson DP, Vanhatalo A, and Wilkins BW. Physiological demands of running at 2-hour marathon race pace. 05 NOV 2020https://doi.org/10.1152/japplphysiol.00647.2020
