The effect of various arm and walking conditions on postural dynamic stability when recovering from a trip perturbation
Hossein Gholizadeh 
Allen Hill
Julie Nantel
Background
Appropriately responding to unexpected perturbations, such as a trip, is critical to sustain balance and avoid falling during walking.
Research question
How do arm motion and walking asymmetry affect postural stability when recovering from a trip perturbation?
Methods
Fifteen healthy young individuals, who had no experience with treadmill induced perturbations, participated in this study. The Computer-Assisted Rehabilitation Environment system (CAREN-Extended) was used to simulate unexpected perturbations while walking symmetrically and asymmetrically with various arm swings (normal, bound, released). Whole-body angular momentum (WBAM), peak trunk angular velocities, Center of Mass (COM), step width and stance time were analyzed before and when recovering from trip perturbations.
Results
Participants were able to recover their postural stability within three strides following the sudden anterior-posterior trip perturbation. The perturbation increased peak trunk angular velocity, the COM excursion and WBAM but did not affect stance time and step width. The arm conditions had significant effects on peak trunk angular velocity, WBAM and step width during pre-perturbation. Walking conditions had a significant effect on all variables during pre-perturbation; however, post-perturbation showed significant effects only for peak trunk angular velocity, WBAM, and COM.
Significance
Unexpected perturbation had effects on most of gait variables; nevertheless, participants fully recovered and adapted their gait pattern to sudden perturbations even without using their arms while walking symmetrically and asymmetrically. Arm movements could help young individuals recover after a perturbation but are not essential for perturbations of moderate magnitude. The effect of medial-lateral perturbations on gait still need to be investigated.
gait, perturbation, trip, dynamic stability, accidental falls
Copyright
Citation
@article{gholizadeh2019,
author = {Gholizadeh, Hossein and Hill, Allen and Nantel, Julie},
title = {The Effect of Various Arm and Walking Conditions on Postural
Dynamic Stability When Recovering from a Trip Perturbation},
journal = {Gait \& Posture},
volume = {76},
pages = {284-289},
date = {2019-12-26},
url = {https://www.sciencedirect.com/science/article/pii/S0966636219317631},
doi = {10.1016/j.gaitpost.2019.11.010},
langid = {en},
abstract = {**Background** Appropriately responding to unexpected
perturbations, such as a trip, is critical to sustain balance and
avoid falling during walking. **Research question** How do arm
motion and walking asymmetry affect postural stability when
recovering from a trip perturbation? **Methods** Fifteen healthy
young individuals, who had no experience with treadmill induced
perturbations, participated in this study. The Computer-Assisted
Rehabilitation Environment system (CAREN-Extended) was used to
simulate unexpected perturbations while walking symmetrically and
asymmetrically with various arm swings (normal, bound, released).
Whole-body angular momentum (WBAM), peak trunk angular velocities,
Center of Mass (COM), step width and stance time were analyzed
before and when recovering from trip perturbations. **Results**
Participants were able to recover their postural stability within
three strides following the sudden anterior-posterior trip
perturbation. The perturbation increased peak trunk angular
velocity, the COM excursion and WBAM but did not affect stance time
and step width. The arm conditions had significant effects on peak
trunk angular velocity, WBAM and step width during pre-perturbation.
Walking conditions had a significant effect on all variables during
pre-perturbation; however, post-perturbation showed significant
effects only for peak trunk angular velocity, WBAM, and COM.
**Significance** Unexpected perturbation had effects on most of gait
variables; nevertheless, participants fully recovered and adapted
their gait pattern to sudden perturbations even without using their
arms while walking symmetrically and asymmetrically. Arm movements
could help young individuals recover after a perturbation but are
not essential for perturbations of moderate magnitude. The effect of
medial-lateral perturbations on gait still need to be investigated.}
}