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[This post was originally written in February 2017 on a predecessor to this page and re-posted here to this site in June 2017, hence it predates the official Nike Breaking2 attempt in Monza, Italy].

As a professional coach who has had the great fortune to spend time training with and learning from world class sub 2:04 marathon runners and their coaches I thought I’d share some personal insight into the concept of the 1:59:59 marathon. On a personal level it’s even more relevant for me right now as I embark on a new and exciting coaching journey with a sub 2:20 marathoner aiming to break 2:10 and possibly even reach their theoretical lifetime full potential of approx 2:06.

The Theory

To break 2 hours the successful runner will have to average 4:34/mile or 2:53/km across the marathon distance. To put this in more tangible terms, if we take the current world number one and Olympic Champion marathoner Eliud Kipchoge and we look at his theoretical potential. His best time over the half marathon is 59:25 (Lille, 2012) which equates to an average pace of 4:32/mile or 2:49/km. Knowing that breaking 2 hours requires 2:53/km then clearly Kipchoge would have to train to hold close to his half marathon PR for twice the distance.

average 4:34/mile or 2:53/km across the marathon distance

This sounds insanely difficult given how hard he trains already. But it does show that it is theoretically at least, possible. Currently Kipchoge’s best marathon time is 2:03:05 and hence he would have to run 8s/mile faster to break 2 hours. However as anyone who watched it will attest to, this London 2016 PR could have been much quicker if only Kipchoge had kept a closer eye on his splits in the last 7 km. In fact its not unreasonable to suggest that he could have broken the world record that day and run comfortably under 2:03:00.

In more detail the prospective 1:59:59 marathoner will need to have very high levels of max aerobic fitness such as VO2 max > 80 mL/kg/min, combined with the metabolic conditioning to sustain a high percentage of this max capacity for the race duration (>80%), and then ontop of that be exceptionally economical in how their neuromuscular system mechanically converts this into speed on the course i.e a likely oxygen cost of less than 180 mL/kg/km.

Side note, one of the most exceptional endurance athletes to be measured in terms of physiological attributes is 3 time Tour de France winner Chris Froome. In France in 2015 he was measured as having a VO2 max of 89 mL/kg/min as well as exceptional ability to hold a high threshold power value and extremely high levels of economy.

By comparison Paula Radcliffe’s oxygen demand versus uptake profile in the year that she set the current women’s record (2003) was 6.7/7.4 liters per kg using more oxygen than she could supply. It has been postulated that the runner that breaks the 2 hour mark, Kipchoge or not would need a more balanced relationship in their profile where demand and supply are more closely matched in fact the same i.e. 8/8 liters per kg. Paula’s exceptional running economy (VO2 uptake at 16kph) was measured in the lab by Prof Andy Jones in 2003 as 175 mL/Kg/km and then again in 2005 as 165 mL/Kg/Km. These are extremely efficient numbers at the far extreme end of the current global database. However it shows that a figure of 175 is attainable.

extremely efficient numbers at the far extreme end of the global database

Wearing my coaching hat I tend to immediately be attracted to parameters that can be affected and significantly improved through optimised and highly individualised training. Of the three parameters mentioned above, this for me means running economy. Our current best knowledge of VO2 max is that it has a natural ceiling and that after 1 or 2 years of intense focused training at a high level the athlete will have already found their naturally highest VO2 max. Holding a high percentage of that VO2 max effort for 26.2 miles is tough and requires hard training but the world’s best triathletes have already demonstrated that this can be achieved and the world’s top marathoners are close if not already pretty much there. So it is really running economy that is most intriguing.

Unlike VO2 max which can be measured and hence screened in hyper talented individuals, running economy improvement takes long term commitment  to skilled training and coaching. Getting to the absolute maximum limit of an athletes running economy means identifying all the work and power inefficiencies and then correcting them through competency and form training and specific strength training. The runners must hold up their torsos (center of mass) with just enough tension and without too much vertical displacement, ultilise the most efficient joint angles throughout the gait cycle and optimise stride length, frequency and contact time with near perfect neuromuscular activation and synchronisation.

Most importantly there has to be no form break down. Re-occurring poor ground contacts or persistent asymmetrical dominance of one muscle group or side creates work and power inefficiencies that lead to compromised running economy. It’s common in tougher marathon majors like Boston and New York to observe this form break in the last 5-10km and to concurrently witness the runners pace drop.

most importantly there has to be no form break down

Optimising metrics such as Efficiency factor (relationship between heart rate and pace), Power output (bulk) per kg body mass, Leg stiffness and Vertical oscillation (maximum vertical movement per stride) will be important in achieving the best possible numbers for running economy. Clearly the runner will need the maximum efficiency to hold the required 2:53/km record pace for lowest possible heart rate. Galen Rupp’s training under Alberto Salazar prior to the 2016 US Olympic marathon trials in LA shows that this is likely achievable. Salazar recorded Rupp’s heart rate throughout a 20 mile run at an average of 4:52/mile or 3:00min/km. Whilst his heart rate held at 149bpm and did not exceed 150bpm (Galen Rupp was 29 years old at the time).

Equally the runner will need access to a large amount of power but only use the minimal amount of mechanical power to hold the record pace. One way of helping to achieve this is through stiffening up certain key parts of the body to eliminate energy and power loss. A more rigid hip core area and limited knee flexion in stance would be important. For this, excess flexibility in critical joints would have to be avoided. In the case of Paula Radcliffe, between 1992 and 2003 her measured sit and reach flexibility numbers got worse meanwhile her running economy and performance got significantly better.

sit and reach flexibility numbers got worse meanwhile running economy and performance got significantly better

These are a few of my thoughts around running a sub 2 hour marathon specifically diving into the physiological metrics and the importance of achieving fantastic running economy. Obviously, as many other authors have reported recently there are a host of other factors involved that are just as important such as for example, psychology and mental resilience.

M.Sc, MSci, B.Sc, CSCS, NSCA-CPT, XPS, CGS. Malc Kent is a professional coach, internationally respected applied scientist and former world class athlete. His services include sports coaching and mentoring, workplace coaching and biomechanics coaching.

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