Fig. 2

Correlation of speeds measured while walking overground (\({\varvec{v}}_{\varvec{O}\varvec{G}}\)) and on the self-paced treadmill (\({\varvec{v}}_{\varvec{S}\varvec{P}\varvec{T}}\)). Colored circles show each participant’s average speed from two overground trials and two self-paced treadmill trials, both while wearing normal shoes. Whisker ends indicate speed in each trial. The linear model (solid), identity line (dashed), and ± 5% from identity (gray shaded region) are shown