TY - JOUR
T1 - Centre of pressure modulations in double support effectively counteract anteroposterior perturbations during gait
AU - van Mierlo, M.
AU - Vlutters, M.
AU - van Asseldonk, E. H.F.
AU - van der Kooij, H.
N1 - Funding Information:
This work is part of the research program Wearable Robotics with project number P16-05 , which is (partly) funded by the Dutch Research Council (NWO) .
Publisher Copyright:
© 2021 The Authors
PY - 2021/9/20
Y1 - 2021/9/20
N2 - Centre of mass (CoM) motion during human balance recovery is largely influenced by the ground reaction force (GRF) and the centre of pressure (CoP). During gait, foot placement creates a region of possible CoP locations in the following double support (DS). This study aims to increase insight into how humans modulate the CoP during DS, and which CoP modulations are theoretically possible to maintain balance in the sagittal plane. Three variables sufficient to describe the shape, length and duration of the DS CoP trajectory of the total GRF, were assessed in perturbed human walking. To counteract the forward perturbations, braking was required and all CoP variables showed modulations correlated to the observed change in CoM velocity over the DS phase. These correlations were absent after backward perturbations, when only little propulsion was needed to counteract the perturbation. Using a linearized inverted pendulum model we could explore how the observed parameter modulations are effective in controlling the CoM. The distance the CoP travels forward and the instant the leading leg was loaded largely affected the CoM velocity, while the duration mainly affected the CoM position. The simulations also showed that various combinations of CoP parameters can reach a desired CoM position and velocity at the end of DS, and that even a full recovery in the sagittal plane within DS would theoretically have been possible. However, the human subjects did not exploit the therefore required CoP modulations. Overall, modulating the CoP trajectory in DS does effectively contributes to balance recovery.
AB - Centre of mass (CoM) motion during human balance recovery is largely influenced by the ground reaction force (GRF) and the centre of pressure (CoP). During gait, foot placement creates a region of possible CoP locations in the following double support (DS). This study aims to increase insight into how humans modulate the CoP during DS, and which CoP modulations are theoretically possible to maintain balance in the sagittal plane. Three variables sufficient to describe the shape, length and duration of the DS CoP trajectory of the total GRF, were assessed in perturbed human walking. To counteract the forward perturbations, braking was required and all CoP variables showed modulations correlated to the observed change in CoM velocity over the DS phase. These correlations were absent after backward perturbations, when only little propulsion was needed to counteract the perturbation. Using a linearized inverted pendulum model we could explore how the observed parameter modulations are effective in controlling the CoM. The distance the CoP travels forward and the instant the leading leg was loaded largely affected the CoM velocity, while the duration mainly affected the CoM position. The simulations also showed that various combinations of CoP parameters can reach a desired CoM position and velocity at the end of DS, and that even a full recovery in the sagittal plane within DS would theoretically have been possible. However, the human subjects did not exploit the therefore required CoP modulations. Overall, modulating the CoP trajectory in DS does effectively contributes to balance recovery.
KW - Centre of pressure
KW - Double support
KW - Human balance
KW - Linear inverted pendulum model
KW - UT-Hybrid-D
UR - http://www.scopus.com/inward/record.url?scp=85111210077&partnerID=8YFLogxK
U2 - 10.1016/j.jbiomech.2021.110637
DO - 10.1016/j.jbiomech.2021.110637
M3 - Article
AN - SCOPUS:85111210077
SN - 0021-9290
VL - 126
JO - Journal of biomechanics
JF - Journal of biomechanics
M1 - 110637
ER -