BJMB
Brazilian Journal of Motor Behavior
Research Article
!
Veneroso,
Segundo, Godoi
2021
VOL.15
N.2
65 of 78
65 of 78
Underlying physiological and biomechanical mechanisms related to postural control of
Parkour practitioners: a pilot study
ANDRÉ F. V. VENEROSO
1
| PATRICK W. SEGUNDO
1
| DANIELA GODOI
1
1
Dinâmica - Motor Behavior Laboratory, Department of Physical Education, Federal University of São Carlos, São Carlos, SP, Brazil.
Correspondence to:!Daniela Godoi, Dinâmica - Motor Behavior Laboratory, Department of Physical Education, Federal University of São Carlos - Rod. Washington Luís,
km 235 - SP-310, CEP 13565-905, São Carlos, SP, Brazil.
email: danielagodoij@ufscar.br
https://doi.org/10.20338/bjmb.v15i2.207
HIGHLIGHTS
Tracers show a lower amount of sway than
physically active subjects.
Tracers show a lower amplitude of the torque
required for stabilization than physically active
subjects.
Tracers show a higher degree of postural
stability than physically active subjects.
The use of sensory inputs to control balance is
different in tracers.
The underlying physiological and
biomechanical mechanisms related to postural
control are different in tracers.
ABBREVIATIONS
ANOVAs Analyses of variance
AP Anterior-posterior
CoP Center of pressure
MD Mean distance between
successive peaks
ML Medial-lateral
MP Mean value of the peaks
MT Mean time interval between
successive peaks
RMS Root mean square
SDC Sway Density Curve
PUBLICATION DATA
Received 19 10 2020
Accepted 05 12 2020
Published 01 06 2021
BACKGROUND: Parkour can be seen as a sport, an art, a philosophy, a state of mind, an art of living. Practitioners
(known as “tracers”) have to overcome obstacles in their path by adapting their movements to the given
environment to reach somewhere or something or to escape from someone or something. However, the
knowledge about the underlying mechanisms related to postural control in tracers is still lacking.
AIM: To examine the postural control in tracers using global, structural, and spectral stabilometric descriptors.
METHOD: Five tracers and five controls, all-male, stood upright for 30 seconds, under different conditions of vision
(open or closed eyes), surface (soft or rigid), and base of support (bipedal, semi-tandem, or Parkour stance).
RESULTS: In more challenging conditions, the tracers compared to controls, showed a lower amount of sway,
needed less postural commands, and used sensory information to control balance differently.
CONCLUSION: Tracers have better postural control than controls. Moreover, although current findings are based
on data from a small number of subjects, the results suggest that these differences between groups are related
to different underlying physiological and biomechanical mechanisms related to postural control.
KEYWORDS: Tracers | Postural Control | Sensory Information | Control Mechanisms
INTRODUCTION
Postural control involves not only balance but also the ability to assume and
maintain a desired orientation; so, every movement involves postural control.
1
Therefore,
the postural control system's accurate functioning allows us to interact with the environment
properly. However, for this to occur, it is necessary to get information about the environment,
which is possible from multiple sources of sensory inputs.
Sensory information comes from, mainly, the visual, vestibular, and somatosensory
sensory systems.
2
Nevertheless, sensory integration for postural control is not merely a
summation of inputs from different sensory systems, but a non-linear process named
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sensory reweighting.
3,4
In this way, whenever environmental or central nervous system
conditions change, sensory inputs must be dynamically reweighed to optimize the control of
postural stability.
3
This dynamic sensory reweighting process allows us to properly perceive the
environment and then appropriately act in that environment. Thus, the action is influenced
by the perceived environment, and that action may influence the perceived environment.
5
In
Gibson’s words, action leads to the detection of information, and information plays a vital
role in controlling the action.
6
So, it can be said that people perceive to move and move to
perceive
7
.This mutual dependency of action and perception is designated as the formation
of an action-perception pattern
5
or cycle
1
; that is, an action-perception coupling.
7
Interestingly, postural control functioning is not ready at the beginning of life; on the
contrary, it changes throughout life. As a result, the ability to select and use sensory
information for the appropriate and consistent functioning of the postural control system
according to the environmental demands depends on age,
4,8,9,
and practice.
10,11
For this reason, several studies have examined the sport training effects on postural
control
11,12,13,14
in experimental conditions that manipulated vision
11,12,14
and
somatosensory
14
information. And, among athletic training, Parkour emerge as an
interesting option.
Parkour is derived from the French word parcourt meaning “obstacle course,” and
was created in Paris's suburbs by David Belle and Sébastien Foucan.
15
It is defined as an
art allowing to pass any obstacle to go from one point of space to another with the
possibilities offered by the human body.
16
Thus, Parkour involves practitioners (called
“tracers”) training to overcome obstacles in their path by adapting their movements to the
given environment to reach somewhere or something or escaping from someone or
something.
17
There are several specific Parkour movements, and these movements vary
according to environmental conditions. In general, it can be mentioned vaults (movements
that involves overcoming an obstacle by climbing, jumping, or diving over an obstacle while
using feet, hands, or not touching it at all), precision jumps (jump from or jump to a specific
point from a stationary position), wall runs (horizontal or vertical runs, used to get over a wall
too high), and “cat leaps” or arm leap (jump used to land on a ledge, a wall, or a fence).
18
Due to the rapid growth of this activity worldwide
16,19
and the fact that this activity
had been recognized as a discipline by the International Gymnastics Federation, studies
have been conducted to understand tracer’s performance better. Most studies have been
interested in injuries caused by this activity,
15
sociocultural aspects,
16,19
strength and power
performance,
20
and biomechanics characteristics of landing.
17
However, few studies have been carried out to evaluate the effect of such practice
on postural control. To the best of our knowledge, there are only two studies that
investigated postural control of tracers. One pilot study
18
that investigated postural control
during the maintenance of a standing upright position, and another study
21
that investigated
postural control during Parkour landing. Nonetheless, in these studies, postural stability was
described by linear descriptors (global descriptors such as the area of the center of pressure).
Thus, it was possible to describe the amount of sway but not the dynamics that regulate
balance control.
To describe and understand these underlying physiological and biomechanical
mechanisms related to postural control, more robust analyses should have been employed,
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Brazilian(Journal(of(Motor(Behavior(
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Veneroso,
Segundo, Godoi
2021
VOL.15
N.2
67 of 78
67 of 78
including spectral and structural stabilometric descriptors. In this sense, it can be mentioned
some analyses such as the Sway Density Curve (SDC) analysis of the center of pressure
(CoP),
22
which provide information related to the process of generating sequences of
postural commands,
23,24,25
or spectral analysis in different bands of frequency, which
assumes that different frequency bands are related to control based on different sources of
sensory inputs
12,13
and, therefore, provides information about the use of different sources of
sensory inputs by the postural control system.
Thereby, overall knowledge about the underlying physiological and biomechanical
mechanisms related to postural control in tracers is still lacking. Hence, there is a need to
gain insight into the dynamics that regulate these practitioners' balance control.
Therefore, the present pilot study aimed to examine the postural control in tracers
using global, structural, and spectral stabilometric descriptors. It was hypothesized that
tracers (a) would show a lower amount of sway (global descriptors), (b) would need less
postural commands to control balance (structural descriptors), and (c) would use sensory
inputs in a different way (spectral descriptors), when compared to control subjects with no
prior experience in Parkour.
METHODS
Participants
Ten male participants (tracers and controls) volunteered for this study. The Tracer
group (n=5; mean age: 21.40±2.70 years) had participated in Parkour training for at least
one year. They trained around two times per week, and each training session lasted between
70 and 80 minutes, divided into four parts: 1) 5-10 min of warm-up activities; 2) 25-30 min of
specific Parkour movements, such as vaulting, climbing, precision jump, quadrupedal
movement, wall run; 3) 15-20 min of path activities where the goal is to go from one point of
space to another by using specific Parkour moves to overcome obstacles in their path by
adapting their movements to the given environment; and 4) 15-20 min of challenging
activities which included tasks (either technical Parkour movements or path activities) more
difficult than those practiced earlier in that session training.
The Control group (n=5; mean age: 23.80±2.95) had been involved in other physical
activities for at least one year, and had no prior experience in Parkour training. All
participants gave their informed consent after the procedures were fully explained. The study
was conducted following the Declaration of Helsinki and approved by the Institutional Review
Board of the Federal University of São Carlos (3.021.618/2018).
Procedures
Participants were asked to maintain an upright position barefoot on a force platform
(Advance Mechanical Technology Inc.– AMTI AccuGait) with their arms alongside their
body, look straight ahead, and maintain their position for 30 seconds. All participants
underwent different conditions of vision (open or closed eyes), surface (soft or rigid), and
base of support (bipedal stance, semi-tandem stance, or Parkour landing stance) (Figure 1).
These conditions were manipulated to generate different levels of challenge to the postural
control system, which is considered a classic strategy to unveil the postural control
functioning.
3