Physiological demands of running at 2-hour marathon race pace

The requirements of running a 2-h marathon have been extensively debated but the actual physiological demands of running at similar to 21.1 km/h have never been reported. We therefore conducted laboratory-based physiological evaluations and measured running economy (O-2 cost) while running outdoors at similar to 21.1 km/h, in world-class distance runners as part of Nike's "Breaking 2" marathon project. On separate days, 16 world-class male distance runners (age, 29 +/- 4yr; height, 1.72 +/- 0.04 m; mass, 58.9 +/- 3.3 kg) completed an incremental treadmill test for the assessment of (V) over dotO(2peak), O-2 cost of submaximal running, lactate threshold and lactate turn-point, and a track test during which they ran continuously at 21.1km/h. The laboratory-determined (V) over dotO(2peak) was 71.0 +/- 5.7 mUkg/min with lactate threshold and lactate turn-point occurring at 18.9 +/- 0.4 and 20.2 +/- 0.6 km/h, corresponding to 83 +/- 5% and 92 +/- 3% (V) over dotO(2peak). respectively. Seven athletes were able to attain a steady-state (V) over dotO(2) when running outdoors at 21.1km/h. The mean O-2 cost for these athletes was 191 +/- 19 mL/kg/km such that running at 21.1 km/h required an absolute N/O-2 of similar to 4.0 L/min and represented 94 +/- 3% (V) over dotO(2peak). We report novel data on the O-2 cost of running outdoors at 21.1 km/h, which enables better modeling of possible marathon performances by elite athletes. Using the value for O-2 cost measured in this study, a sub 2-h marathon would require a 59 kg runner to sustain a (V) over dotO(2) of approximately 4.0 L/min or 67 mL/kg/min. NEW & NOTEWORTHY We report the physiological characteristics and O-2 cost of running overground at similar to 21.1 km/h in a cohort of the world's best male distance runners. We provide new information on the absolute and relative O-2 uptake required to run at 2-h marathon pace.