Factors affecting running economy: An examination of the visual assessment of running economy and the influence of footwear

Abstract

ABSTRACT

Persons with a good running economy (RE) consume less oxygen per unit of body mass than those with poor RE at the same velocity. While many factors affect RE, the extent footwear can affect RE remains elusive. Furthermore, the capability of distance running coaches to visually differentiate runners by RE is unknown. The first study compared RE and step frequency (SF) among recreational distance runners at 50% and 70% of velocity at VO2max (vVO2max), while running barefoot, in minimal shoes, and in normal running shoes. The second study determined the ability of distance-running coaches to visually classify runners by RE and identify the criteria used to rank the runners.

In the first study, RE was not significantly altered by footwear at either 50% vVO2max (p = .89) or 70% vVO2max (p = .13). However, large individual variations in RE were seen in certain runners across footwear conditions. Running barefoot produced higher SF than running in the minimal condition at 50% vVO2max (p = .007). At 70% vVO2max, SF was higher in the barefoot condition than both the minimal (p < .001) and standard conditions (p < .001). Furthermore, there was a higher SF in the minimal condition than the standard condition at 70% vVO2max (p = .007). In the second study, the coaches classified 17.9% of runners or less than 1 in 5 runners correctly. Neither years coaching (r = .12, p = .184) nor years in competitive running (r = -.06, p = .484) were related to the accuracy of classifying RE. Overall, footwear did not significantly affect RE despite individual variations and significant differences in step frequency among the shoe conditions. Runners should consider individual biomechanical and physiological traits before making a footwear change in order to improve RE. Furthermore, the ability of distance running coaches to rank RE was not shown to be accurate or related to coaching characteristics. Consideration should be given to bridging the gap between coaching knowledge and the scientific literature.