Human‐in‐the‐loop optimized rocker profile of running shoes to enhance ankle work and running economy

Increasing the efficiency at which muscles generate mechanical power could
improve running economy. A potential way to reduce muscle fiber shortening velocities
and enhance energy storing of the Triceps Surae is changing their gear ratio
at the ankle via optimization of shoe rollover profile. The aim of the current study
was to individually optimize rollover profile of rocker shoes via human‐in‐the‐loop
optimization to maximize positive ankle work to redistribute joint work from the hip
and knee to the ankle and improve running economy. A total of 10 runners ran on a
treadmill with experimental rocker shoes in which apex position and angle were
optimized using an evolution algorithm to maximize positive ankle work. We
compared experimental shoes with optimal settings, standard settings, and control
shoes in terms of biomechanics and running economy. Optimal apex parameters
differed considerably between participants. The optimal condition resulted in higher
positive ankle work and a higher proportional share of the ankle in the total positive
lower limb work compared to the standard condition. A difference in running
economy between these conditions was not found. Human‐in‐the‐loop optimization
can redistribute joint work from the hip and knee to the ankle by individually
optimizing apex parameters. Although this did not improve running economy, the
study showed that human‐in‐the‐loop optimization could improve the effectiveness
of footwear with respect to the selected optimization parameter on an individual
level.