Sagittal and frontal interplane balance control variability is minimized at preferred walking speed in healthy young...

Reduced preferred walking speed (PWS) is a known indicator of increased fall risk, particularly sideways falls in individuals with reduced physical capacity, often attributed to decreased mediolateral stability in the frontal plane. The underlying mechanisms and the impact of walking speed on interplane balance control coordination remain unclear. The current study aimed to develop a novel analytical framework for quantifying the sagittal and frontal interplane coordination of center of mass (COM)-center of pressure (COP) control and its variabilities during level walking via continuous relative phase (CRP) angles and to study the walking speed effects. Fifteen young adults walked at PWS, slower and faster, whereas the COM-COP inclination angles (IAs) and their rates of change (RCIA) were measured to calculate interplane CRP patterns. The deviation phases (DP) of CRP curves quantified the variability of interplane coordination. The interplane balance control coordination and variability were significantly influenced by walking speed, with minimum DP values occurring during double limb support at PWS. Walking at one's PWS represents the best compromise for minimizing control variability between the sagittal and frontal planes. This novel approach highlights the role of interplane balance control variability in determining PWS in young adults and emphasizes the importance of monitoring these variables for fall risk assessment.NEW & NOTEWORTHY The current study described a novel approach based on continuous relative phase analysis to quantify the interplane coordination of balance control during gait in young adults. This approach highlights the role of interplane balance control variability in determining preferred walking speed in young adults and emphasizes the importance of monitoring these variables for fall risk assessment in diverse populations.