The metabolic cost of overcoming air resistive forces in distance running

Abstract

We lack a mechanistic understanding of the relationship between aerodynamic drag forces and metabolic power during running. Further, the energetic and time savings possible from reducing aerodynamic drag (drafting) are still unclear due to the different methods previously assumed for converting from force reductions to metabolic power savings. Here, we quantified how small horizontal impeding forces (equivalent to aerodynamic forces) affect metabolic power and ground reaction forces over a range of velocities in competitive runners. In three sessions, 12 runners completed six 5-minute trials with 5 minutes of recovery in-between. We tested one velocity per session (12, 14 and 16 km/h), at three horizontal impeding force conditions (0, 4 and 8 N). On average, metabolic power increased by 6.13% per 1% body weight of horizontal impeding force but varied considerably between individuals. With greater horizontal impeding force, braking impulses decreased while propulsive impulses increased (p < 0.001). Across running velocities, the changes in braking and propulsive impulses with greater impeding force were correlated (r = -0.97; p < 0.001), but were not related to individual changes in metabolic power. We estimate that at ~2-hour marathon pace, overcoming air resistive force comprises 8.52% of the gross metabolic power on average.

Can we quantify the benefits of “super spikes” in track running?

“…For the Vaporfly, the metabolic savings were 4%, but the time savings are smaller [6][7][8][9]. The exact time savings depend on running velocity, the runner's individual metabolic savings from the shoes at that velocity, and their individual metabolic rate -velocity relation (including their individual efficiency to overcome air resistance [54]). Therefore, in the case of marathon shoes, while we have a number for the average metabolic savings across 18 high-caliber, male runners over a range of speeds (~3hr -~2:20hr marathon pace) in one specific model (i.e.…”

Can We Quantify the Benefits of “Super Spikes” in Track Running?

“…For the Vaporfly, the metabolic savings were 4%, but the time savings are smaller [ 6 – 9 ]. The exact time savings depend on running velocity, the runner’s individual metabolic savings from the shoes at that velocity, and their individual metabolic rate—velocity relation (including their individual efficiency to overcome air resistance [ 64 ]). Therefore, in the case of marathon shoes, while we have a number for the average metabolic savings across 18 high-caliber male runners over a range of speeds (~ 3 h to ~ 2:20 h marathon pace) in one specific model (i.e.…”