Comparing temporal characteristics of stepping-in-place and overground walking in healthy adults

Stepping in place (SIP) is commonly used as a balance and locomotor training method for high fall-risk populations. While SIP simulates overground (OG) walking, how well its walking stability and temporal characteristics represent OG remains unclear. This study hypothesized that dynamic stability and temporal metrics of SIP would positively correlate with OG walking. Seventeen healthy adults performed OG walking and SIP tasks while wearing triaxial accelerometers on the pelvis and lower limbs. Heel strike and toe-off events were identified using a validated accelerometer-based algorithm and were used to calculate short-term Lyapunov exponents (STLE) and temporal characteristics. Non-parametric methods (Kendall's tau and Wilcoxon signed-rank tests) were used to assess associations and differences between conditions. Moderate associations were found between OG walking and SIP for mean stride time (MST; τ = 0.397, p = 0.026). Wilcoxon tests revealed significant differences between conditions in MST (p = 0.01), step time variability (p < 0.001), and double support duration (p < 0.001) with SIP demonstrating greater variability. The non-significant difference in STLE between SIP and OG walking suggest that SIP may be an appropriate therapeutic intervention or diagnostic tool that mimics certain temporal aspects of walking. Further research should examine directional components of stability and the effects of cueing and fatigue on SIP performance.