Does shoe heel-to-toe drop have an influence on performance in downhill trail running?

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Computer Methods in Biomechanics and Biomedical
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Does shoe heel-to-toe drop have an influence on
performance in downhill trail running?
Thomas Defer, Robin Juillaguet, Marlène Giandolini, Sebastien Pavailler,
Nicolas Horvais, Johan Cassirame & Gregory Doucende
To cite this article: Thomas Defer, Robin Juillaguet, Marlène Giandolini, Sebastien Pavailler,
Nicolas Horvais, Johan Cassirame & Gregory Doucende (2019) Does shoe heel-to-toe drop have
an influence on performance in downhill trail running?, Computer Methods in Biomechanics and
Biomedical Engineering, 22:sup1, S238-S239, DOI: 10.1080/10255842.2020.1714254
To link to this article: https://doi.org/10.1080/10255842.2020.1714254
© 2020 The Author(s). Published by Informa
UK Limited, trading as Taylor & Francis
Group
Published online: 22 May 2020.
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Does shoe heel-to-toe drop have
an influence on performance in
downhill trail running?
Thomas Defer
a
, Robin Juillaguet
b
, Marl
ene
Giandolini
c
, Sebastien Pavailler
c
, Nicolas Horvais
c
,
Johan Cassirame
d,e
and Gregory Doucende
a,b
a
Laboratoire Europ
een Performance Sant
e Altitude, EA4604,
Universit
e de Perpignan Via Domitia, Font Romeu, France;
b
SAS Perftrail, France;
c
Innovation and Sport Science
Laboratory, Salomon SAS, Epagny-Metz-Tessy, France;
d
Plateforme Exercice Performance Sant
e Innovation, Universit
e
de Bourgogne Franche Comt
e, Besanc¸on, France;
e
EA 7507,
Laboratoire Performance, Sant
e, M
etrologie, Soci
et
e,
Reims, France
1. Introduction
Trail running (TR) is characterized by sequences of
uphill and downhill performed in a natural environ-
ment. Recently, studies investigated performance fac-
tors specific to TR. During a full race of TR,
Ehrstr€
om et al. (2018) highlighted that performance is
depending on (1)
_
VO
2max, (2) running economy
and (3) local endurance of lower limbs. However, elite
athletes seem to make a difference in downhill sec-
tions more that in uphill during short TR races. For
that matter, Juillaguet et al. pointed out that perform-
ance in downhill was related to (1) muscular (high
quadriceps rate force development), (2) perceptive
(fast visual based decision making), (3) psychological
(disposition to take risks) and (4) biomechanical (low
percentage of rear foot strikes) factors (Juillaguet
et al. 2018). However, Horvais and Samozino (2013)
highlighted that shoe drop (i.e., the difference of
height between heel and toes in the shoe) highly
influenced foot strike pattern (FSP). Indeed, runners
changed their FSP from rear foot strike to mid/fore
foot strike when using low drop shoes. Moreover, low
drop shoes may also induce a better running econ-
omy, especially on flat sections (Vercruyssen et al.
2016). Given that these studies only investigated flat
and uphill sections, no relevant information could be
found for downhill sections. Well, Juillaguet et al.
pointed out that performance in downhill was influ-
enced by biomechanical factor (low percentage of rear
foot strike). The purpose of this study was to deter-
mine whether using shoes with different drops can
increase performance in downhill. It was hypothesized
that trail-runners would be faster in a short downhill
section with lower drop shoes.
2. Method
2.1. Participants
Thirteen male experienced trail-runners participated
to this study (age: 23 ± 5 years, height: 180 ± 6 cm,
weight: 66 ± 4 kg, training/week: 5 ± 2, experience in
TR: 4 ± 2 years).
2.2. Study design
The study took place in a natural environment. 800-
meters downhill section with 200 meter negative ele-
vations (i.e. gradient of approximately 25%). A short
section was chosen to eliminate the influence of
neuromuscular fatigue. Subjects had to realize a spe-
cific warm-up, followed by a downhill preview. Then,
they had to realize two timed downhills with two
pairs of shoes in a random order: a 4 mm drop shoe
(D4) and an 8 mm drop shoe (D8). Except the drop
difference, all technical features between shoes were
the same. A recovery period of 20 minutes was given
to the subjects between the two downhills.
Participants were instructed to run as fast as possible.
2.3. Data collection
Each participant’s right shoe was equipped with two
triaxials accelerometers (Hikob Agile Fox, Hikob,
Villeurbanne, France). One was placed at the back of
the heel and the other above the metatarsal area.
Accelerometers were secured with adhesive tape.
Accelerations of the three axis were recorded at
1344 Hz directly onto a memory card embedded in
the sensor. All recorded data was analyzed with
SciLab 5.5.2 (Scilab Enterprises, Orsay, France). For
each foot strike, the time between the acceleration
peak of the heel and the metatarsus (THM) was cal-
culated. Then the percentage of rear foot strikes
(%RFS), mid foot strikes (%MFS) and forefoot stries
(%FFS) were determined based on this THM
(Giandolini et al. 2014).
ß20 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group
This is an Open Access article distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives License (http://creativecommons.org/licenses/by-
nc-nd/4.0/), which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is properly cited, and is not altered, transformed,
or built upon in any way.
COMPUTER METHODS IN BIOMECHANICS AND BIOMEDICAL ENGINEERING
2019, VOL. 22, NO. S1, S238–S239
https://doi.org/10.1080/10255842.2020.1714254
19

2.4. Statistical analysis
Data are presented by their mean ± standard devi-
ation. Statistical analysis was performed with the
Statview software (version 5.0). To compare results
according to different conditions, a paired t-test was
used. The relationship between biomechanics (%FFS
and %RFS) and downhill time according to the shoe
assessed using a Pearson’s linear correlation.
Significance threshold was fixed at p<0.05.
3. Results and discussion
Results showed a 3% lower downhill time with the
D4 shoe compared to the D8. Downhill times were
179 ± 28 s and 185 ±24s respectively (Figure 1).
Moreover, %RFS and %MFS were significantly higher
with the D8 shoe than with the D4. Conversely, %FFS
was significantly higher with D4 than with D8.
Therefore, runners were faster with D4 than with
D8. This result is explained by a modification of FSP
from rear/midfoot strike to forefoot strike dominance.
Furthermore, %FFS was higher with D4 than with D8
and there is a relationship between %FFS and per-
formance (Figure 2). Our results are emphasizing
with Juillaguet et al. (2018) which suggest that an
alteration of biomechanical factors will increase
downhill performance. In accordance with this find-
ings, lower drop shoes could also permit improve-
ment of running economy as suggested by
Vercruyssen et al. 2016. This result is also described
by Di Michele and Merni (2014) who highlighted that
higher %FFS is related to lower ground time contact,
leading to better adaptations for trail-runners on spe-
cific and unpredictable tracks.
4. Conclusion
To date, elite athletes are searching marginal gains to
increase performances. Our results showed that using
a low drop shoes (D4) allows modification of FSP
from a rear foot strike pattern to a forefoot strike pat-
tern and thus increase downhill performance. So,
selection of material (shoes with different technical
features) could influence performance in downhill TR.
References
Di Michele R, Merni F. 2014. The concurrent effects of
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KEYWORDS Foot strike pattern; performance; trail running; drop
gregory.doucende@univ-perp.fr
Figure 1. Downhill time with different drop shoes. s: seconds;
D4: 4 mm drop shoe; D8: 8 mm drop shoe.
Figure 2. Relationship between %FFS and downhill performance.
COMPUTER METHODS IN BIOMECHANICS AND BIOMEDICAL ENGINEERING S239