Mapping perceived and actual walking speed during overground locomotion: an initial psychophysical approach in healthy adults

Perceived walking speed is rarely quantified during natural overground locomotion, despite walking velocity being widely used as a marker of locomotor performance. This study examined whether perceived walking speed can be systematically related to overground walking velocity and whether common verbal speed categories have stable meanings across experimental contexts. Fifty-four healthy adults completed two short overground walking experiments while wearing lower-body inertial sensors. In Experiment 1, participants walked at externally instructed slow, comfortable, and fast speeds. In Experiment 2, they produced five self-defined walking speeds across their perceived range, from very slow to very fast, so that the central level represented an intermediate point of the continuum rather than a comfortable-speed instruction. After each trial, perceived speed was rated using a 0–100 visual analogue scale. In both experiments, perceived speed ratings and actual walking velocity changed consistently across speed conditions. Participants were also able to construct an ordered five-level speed continuum, with progressive increases in both perceived and measured speed. The association between perceived and actual speed was strong, and sensitivity analyses indicated that the main pattern was not driven by high VAS ratings. Importantly, comparable speed positions did not correspond to identical perceived or actual speeds across experiments. Comfortable walking in the instructed protocol did not coincide with the medium level of the self-defined continuum, supporting the view that common walking-speed instructions are context-dependent rather than fixed locomotor anchors. These findings provide an initial psychophysical approach for studying perceived walking speed during overground locomotion and suggest that subjective speed ratings may help clarify how people interpret walking-speed instructions.