ABSTRACT
People with balance impairments often struggle performing turns or lateral maneuvers, which can increase risk of falls and injuries. Here we asked how people’s mediolateral balance is impacted when walking on non-straight winding paths. Twenty-four healthy adults (12F/12M; 25.8±3.5 yrs) participated. Each walked on each of six paths projected onto a treadmill, comprised of three pseudo-random path oscillation frequency combinations (straight, slowly-winding, quickly-winding), each presented at either wide or narrow width. We quantified stepping errors as the percent of steps taken off each path. We quantified minimum mediolateral Margin of Stability (MoSL) at each step and calculated means (μ) and standard deviations (σ) for each trial. We calculated lateral Probability of Instability (PoIL) as participants’ statistical risk of taking unstable (MoSL < 0) steps. On narrower paths, participants made more stepping errors and walked with smaller μ(MoSL) on all paths (p < 0.001), and exhibited increased PoIL on the straight and slowly-winding paths (p < 0.001). On winding paths, participants made progressively more stepping errors and walked with smaller μ(MoSL) for increasingly sinuous narrow paths (all p < 0.001) and wide quickly-winding paths (all p < 0.001). They also consistently walked with larger σ(MoSL), and increased PoIL on higher sinuosity paths of both widths (all p < 0.001). Though many took numerous unstable steps, no participant fell. Our results demonstrate healthy adults’ ability both to trade off increased risk of lateral instability for greater maneuverability, and to employ highly-versatile stepping strategies to maintain balance while walking.
Competing Interest Statement
The authors have declared no competing interest.
Footnotes
CRediT Author Statement Anna C. Render: Conceptualization, Data Curation, Formal Analysis, Investigation, Methodology, Software, Validation, Visualization, Writing – Original Draft, Writing – Review & Editing.
Joseph P. Cusumano: Conceptualization, Formal Analysis, Funding Acquisition, Methodology, Supervision, Writing – Review & Editing.
Jonathan B. Dingwell: Conceptualization, Data Curation, Formal Analysis, Funding Acquisition, Methodology, Project Administration, Resources, Supervision, Validation, Writing – Review & Editing.
CONFLICT OF INTEREST The authors declare that there is no conflict of interest associated with this work.
Revisions made following refinements to our analysis procedures and in response to reviewer comments. NOTE: We submitted our final data to Dryad. The DOI link provided is correct but not yet "live" while Dryad checks & verifies the submitted files. They provided a review link where the data can be accessed while they complete their checks: http://datadryad.org/stash/share/ymf6tT16YLQ5QeV5osOWrKmtPZ3Gts2JiwAxFPbVTmI