Running in the wild: Energetics explain ecological running speeds.

Area of Science:

• Human physiology
• Biomechanics
• Exercise science

Background:

• Traditionally, human running energy cost was thought constant across speeds.
• Recent lab studies suggest an energy-optimal running speed exists.

Purpose of the Study:

• To analyze free-living runners' preferred speeds.
• To determine if preferred speed aligns with energy efficiency or task demands.

Main Methods:

• Analysis of a large dataset from commercial fitness trackers.
• Comparison of free-living preferred speeds with lab-measured energy-optimal speeds.

Main Results:

• Individual runners maintained a consistent preferred speed across various distances.
• Free-living preferred speeds were indistinguishable from lab-determined energy-optimal speeds.

Conclusions:

• Human running preference is driven by minimizing energy expenditure.
• Findings inform human ecology and athletic training strategies.