Identifying differences in gait adaptability across various speeds using movement synergy analysis

Abstract

Introduction The aim of this study was to identify movement synergies during normal-walking that can differentiate healthy adults in terms of gait adaptability at various speeds. To this end, the association between movement synergies and lower-limb coordination variability or Deviation Phase (DP) was investigated. This study also investigated the moderating effect of movement synergies on the relationship between DP and the smoothness of arm-swing motion (NJI). Method A principal component analysis of whole-body marker trajectories from normal-walking treadmill trials at 0.8m/s, 1.2m/s and 1.6m/s was undertaken. Both DP and NJI were derived from approx. 8 minutes of perturbed-walking treadmill trials. Principal movement components, PMk, were derived and the RMS of the 2nd-order differentiation of these PMk (PAkRMS) were included as independent variables representing the magnitude of neuromuscular control in each PMk. Each PAkRMS were input into maximal linear mixed-effects models against DP and (DP x NJI) respectively. A stepwise elimination of terms and comparison of models using Anova identified optimal models for both aims. Results The principal movement related to the push-off mechanism of gait (PA4RMS) was identified as an optimal model and demonstrated a significant negative effect on DP however this effect may differ considerably across walking-speeds. An optimal model for describing the variance in (DP x NJI) included a fixed-effect of PA6RMS representing Right—Left side weight transfer was identified. Interpretation The hypotheses that individuals who exhibited greater control on specific kinematic synergies would exhibit variations during perturbed walking was substantiated. Supporting evidence for the role of movement synergies during the double-support phase of gait in proactively correcting balance was presented as well as the potential for this approach in targeted rehabilitation. The potential influence of leg dominance on gait adaptability was also discussed. Future studies should investigate further the role of walking-speed and leg dominance on movement synergies and look to generalize these findings to patient populations.

Gymnastics Experience Enhances the Development of Bipedal-Stance Multi-Segmental Coordination and Control During Proprioceptive Reweighting

“…Postural stability requires constant neuromuscular interventions (i.e., actions) to be coupled with perception. The principal accelerations (PA) are used to quantify the actions ("accelerations") performed to maintain bipedal standing in different conditions (Federolf, 2016;Promsri et al, 2018;Wachholz et al, 2019b;Ó'Reilly and Federolf, 2021). Participants in our study showed that AP movements of the hip and knee increased their acceleration during vibration while ankle AP acceleration maintained similar values to those of before vibration.…”

Assessing Walking Stability Based on Whole-Body Movement Derived from a Depth-Sensing Camera

“…In analogy with Newton’s mechanics, the “ principal accelerations ” (PA k ( t )) can be obtained by differentiating PP k ( t ) twice. PA k ( t ) are reported to be associated with the lower-limb electromyographic (EMG) data in postural control tasks [ 14 ], supporting their effectiveness in assessing neuromuscular control of individual PMs not only observed in balance tasks [ 10 , 32 , 33 , 35 , 39 , 40 ], but also in other types of human movement tasks (e.g., walking [ 12 , 41 ] and running [ 15 ]). The word “ principal ” in the titles of the kinematic variables indicates that these variables were obtained through PCA [ 9 ].…”

Walking Stability and Risk of Falls

“…Each PP k ( ) was normalized to an individual’s walking speed [ 23 , 37 ]. Then, the participant-specific largest Lyapunov exponent (LyE) of PP 1–5 ( t ) or PP k _LyE was used to investigate walking stability by computing the rate of divergence of close trajectories in state space (i.e., the ability of the motor system to attenuate small perturbations revealed by the divergence of the trajectories in state space) [ 10 , 16 , 23 , 38 ].…”