TY - JOUR
T1 - Upward perturbations trigger a stumbling effect
AU - Porras, D.C.
AU - Heimler, B.
AU - Jacobs, J.V.
AU - Naor, S.K.
AU - Inzelberg, R.
AU - Zeilig, G.
AU - Plotnik, M.
N1 - Funding Information:
Perception and Action in Complex Environments (PACE) supported this research. The PACE Project has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 642961 . The Israel Ministry of Science, Technology and Space , grant number 3–12072 also supported this research.
Funding Information:
We thank the participants for their time and effort, Or Koren for his help in editing Video 1, and all members of the Center of Advanced Technologies in Rehabilitation for insightful input. DCP thanks the Province of Limburg , Netherlands, for its financial support (Grant 2019-00061 ).
Publisher Copyright:
© 2023
PY - 2023/4/1
Y1 - 2023/4/1
N2 - Background: Vertical perturbations are one major cause of falling. Incidentally, while conducting a comprehensive study comparing effects of vertical versus horizontal perturbations, we commonly observed a stumbling-like response induced by upward perturbations. The present study describes and characterizes this stumbling effect.Methods: Fourteen individuals (10 male; 27 +/- 4 yr) walked self-paced on a treadmill embedded in a moveable platform and synchronized to a virtual reality system. Participants experienced 36 perturbations (12 types). Here, we report only on upward perturbations. We determined stum-bling based on visual inspection of recorded videos, and calculated stride time and ante-roposterior, whole-body center of mass (COM) distance relative to the heel, i.e., COM-to-heel distance, extrapolated COM (xCOM) and margin of stability (MOS) before and after perturbation.Results: From 68 upward perturbations across 14 participants, 75% provoked stumbling. During the first gait cycle post-perturbation, stride time decreased in the perturbed foot and the un-perturbed foot (perturbed = 1.004 s vs. baseline = 1.119 s and unperturbed = 1.017 s vs. baseline = 1.125 s, p < 0.001). In the perturbed foot, the difference was larger in stumbling -provoking perturbations (stumbling: 0.15 s vs. non-stumbling: 0.020 s, p = 0.004). In addition, the COM-to-heel distance decreased during the first and second gait cycles after perturbation in both feet (first cycle: 0.58 m, second cycle: 0.665 m vs. baseline: 0.72 m, p-values<0.001). During the first gait cycle, COM-to-heel distance was larger in the perturbed foot compared to the un-perturbed foot (perturbed foot: 0.61 m vs. unperturbed foot: 0.55 m, p < 0.001). MOS decreased during the first gait cycle, whereas the xCOM increased during the second through fourth gait cycles post-perturbation (maximal xCOM at baseline: 0.5 m, second cycle: 0.63 m, third cycle: 0.66 m, fourth cycle: 0.64 m, p < 0.001).
AB - Background: Vertical perturbations are one major cause of falling. Incidentally, while conducting a comprehensive study comparing effects of vertical versus horizontal perturbations, we commonly observed a stumbling-like response induced by upward perturbations. The present study describes and characterizes this stumbling effect.Methods: Fourteen individuals (10 male; 27 +/- 4 yr) walked self-paced on a treadmill embedded in a moveable platform and synchronized to a virtual reality system. Participants experienced 36 perturbations (12 types). Here, we report only on upward perturbations. We determined stum-bling based on visual inspection of recorded videos, and calculated stride time and ante-roposterior, whole-body center of mass (COM) distance relative to the heel, i.e., COM-to-heel distance, extrapolated COM (xCOM) and margin of stability (MOS) before and after perturbation.Results: From 68 upward perturbations across 14 participants, 75% provoked stumbling. During the first gait cycle post-perturbation, stride time decreased in the perturbed foot and the un-perturbed foot (perturbed = 1.004 s vs. baseline = 1.119 s and unperturbed = 1.017 s vs. baseline = 1.125 s, p < 0.001). In the perturbed foot, the difference was larger in stumbling -provoking perturbations (stumbling: 0.15 s vs. non-stumbling: 0.020 s, p = 0.004). In addition, the COM-to-heel distance decreased during the first and second gait cycles after perturbation in both feet (first cycle: 0.58 m, second cycle: 0.665 m vs. baseline: 0.72 m, p-values<0.001). During the first gait cycle, COM-to-heel distance was larger in the perturbed foot compared to the un-perturbed foot (perturbed foot: 0.61 m vs. unperturbed foot: 0.55 m, p < 0.001). MOS decreased during the first gait cycle, whereas the xCOM increased during the second through fourth gait cycles post-perturbation (maximal xCOM at baseline: 0.5 m, second cycle: 0.63 m, third cycle: 0.66 m, fourth cycle: 0.64 m, p < 0.001).
KW - Balance
KW - Virtual reality
KW - Postural control
KW - Perturbation
KW - Stumbling
KW - CENTER-OF-MASS
KW - DYNAMIC STABILITY
KW - ADAPTIVE-CONTROL
KW - GAIT STABILITY
KW - BALANCE
KW - RESPONSES
KW - WALKING
KW - SLIP
KW - ADJUSTMENTS
KW - STRATEGIES
U2 - 10.1016/j.humov.2023.103069
DO - 10.1016/j.humov.2023.103069
M3 - Article
C2 - 36871477
SN - 0167-9457
VL - 88
JO - Human Movement Science
JF - Human Movement Science
M1 - 103069
ER -