Citation: Taborri, J.; Santuz, A.; Brüll,
L.; Arampatzis, A.; Rossi, S.
Measuring Kinematic Response to
Perturbed Locomotion in Young
Adults. Sensors 2022, 22, 672.
https://doi.org/10.3390/s22020672
Academic Editor: Cosimo Distante
Received: 2 December 2021
Accepted: 14 January 2022
Published: 16 January 2022
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Article
Measuring Kinematic Response to Perturbed Locomotion in
Young Adults
Juri Taborri
1
, Alessandro Santuz
2,3
, Leon Brüll
2,3,4
, Adamantios Arampatzis
2,3
and Stefano Rossi
1,
*
1
Department of Economics, Engineering, Society and Business Organization (DEIM), University of Tuscia,
01100 Viterbo, Italy; juri.taborri@unitus.it
2
Department of Training and Movement Sciences, Humboldt-Universität zu Berlin, 10115 Berlin, Germany;
alessandro.santuz@hu-berlin.de (A.S.); bruell@nar.uni-heidelberg.de (L.B.);
a.arampatzis@hu-berlin.de (A.A.)
3
Berlin School of Movement Science, Humboldt-Universität zu Berlin, 10115 Berlin, Germany
4
Network Aging Research, Heidelberg University, 69117 Heidelberg, Germany
* Correspondence: stefano.rossi@unitus.it; Tel.: +39-07-6135-7049
Abstract:
Daily life activities often require humans to perform locomotion in challenging scenarios.
In this context, this study aimed at investigating the effects induced by anterior-posterior (AP) and
medio-lateral (ML) perturbations on walking. Through this aim, the experimental protocol involved
12 participants who performed three tasks on a treadmill consisting of one unperturbed and two
perturbed walking tests. Inertial measurement units were used to gather lower limb kinematics.
Parameters related to joint angles, as the range of motion (ROM) and its variability (CoV), as well
as the inter-joint coordination in terms of continuous relative phase (CRP) were computed. The AP
perturbation seemed to be more challenging causing differences with respect to normal walking in
both the variability of the ROM and the CRP amplitude and variability. As ML, only the ankle showed
different behavior in terms of joint angle and CRP variability. In both tasks, a shortening of the stance
was found. The findings should be considered when implementing perturbed rehabilitative protocols
for falling reduction.
Keywords: perturbed locomotion; fall risk; inertial sensors; gait analysis; coordination
1. Introduction
Humans have to constantly deal with the challenge to adapt their gait to several en-
vironmental conditions; thus, one of the main roles of the central nervous system (CNS) is
to assure the maintenance of dynamic stability during locomotion on different types of sur-
faces [
1
]. Dynamic stability is defined as the ability to control the body’s center of mass within
a moving base of support [
2
]. An incorrect stability leads to increased risk of falls, which
represent a major public worldwide health issue [
3
]. It was demonstrated that falls mainly
occur if the normal gait is disturbed by external factors, such as slips, trips, and collisions,
as well as arising from volitional movement, such as turning and bending [
4
]. The ability to
correctly respond to a balance perturbation determines whether or not a fall occurs, and it is
shown that this ability can be deteriorated as a consequence of CNS changes and/or muscle
properties [
5
,
6
]. In this context, perturbation-based gait paradigms have reached greater pop-
ularity for the measurement of dysfunctions, diseases, or injuries [
7
–
9
]. Based on the tested
population, perturbations of different natures have been used, ranging from cognitive [
10
]
to visual [
11
] and physical [
12
]. At the same time, several variables have been considered
as sensitive for the quantification of human responses to gait perturbation; among other,
spatio-temporal parameters [
13
], dynamic stability [
13
–
16
], muscular activity [
12
,
17
,
18
],
kinematics [
14
,
16
,
18
], and inter-joint coordination [
3
,
19
] have been the most adopted ones.
As concerns spatio-temporal parameters, Madehkhaksar et al. [
13
] evaluated the
effects of sudden, unexpected mechanical perturbation in medio-lateral (ML) and anterior-
posterior (AP) directions during treadmill walking in 10 healthy young adults. They
Sensors 2022, 22, 672. https://doi.org/10.3390/s22020672 https://www.mdpi.com/journal/sensors
