The influence of weekly training distance on fractional utilization of maximum aerobic capacity in marathon and ultramarathon runners

This study was designed to examine the interrelationships between performance in endurance running events from 10 to 90 km, training volume 3–5 weeks prior to competition, and the fractional utilization of maximal aerobic capacity (% \(\dot V_{O_{2max} } \) ) during each of the events. Thirty male subjects underwent horizontal treadmill testing to determine their \(\dot V_{O_{2max} } \) , and steady-state \(\dot V_{O_2 }\) at specific speeds to allow for calculation of % \(\dot V_{O_{2max} } \) sustained during competition. Runners were divided into groups of ten according to their weekly training distance (group A trained less than 60 km · week⁻¹, group B 60 to 100 km · week⁻¹, and group C more than 100 km · week⁻¹). Runners training more than 100 km · week⁻¹ had significantly faster running times (average 19.2%) in all events than did those training less than 100 km · week⁻¹. \(\dot V_{O_{2max} } \) or % \(\dot V_{O_{2max} } \) sustained during competition was not different between groups. The faster running speed of the more trained runners, running at the same % \(\dot V_{O_{2max} } \) during competition, was due to their superior running economy (19.9%). Thus all of the group differences in running performance could be explained on the basis of their differences in running economy. These findings suggest either that the main effect of training more than 100 km · week⁻¹ may be to increase running economy, or that runners who train more than 100 km · week⁻¹ may have inherited superior running economy. The finding that the maximal horizontal running speed reached during the progressive maximal treadmill test was a better predictor (r=0.72) of running performance at all distances than was the \(\dot V_{O_{2max} } \) (r=0.54) suggests that peak treadmill running speed can predict performance in endurance running events.