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Acute effect of biomechanical foot orthotics on gross efficiency in cyclists affected by an anatomic asymmetry in time trial position

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Computer Methods in Biomechanics and Biomedical
Engineering
ISSN: 1025-5842 (Print) 1476-8259 (Online) Journal homepage: http://www.tandfonline.com/loi/gcmb20
Acute effect of biomechanical foot orthotics on
gross efficiency in cyclists affected by an anatomic
asymmetry in time trial position
A. Bouillod, M. Retali, G. Soto-Romero, E. Brunet, M. Frémeaux, J. Cassirame,
J. Maillot & F. Grappe
To cite this article: A. Bouillod, M. Retali, G. Soto-Romero, E. Brunet, M. Frémeaux, J. Cassirame,
J. Maillot & F. Grappe (2017) Acute effect of biomechanical foot orthotics on gross efficiency
in cyclists affected by an anatomic asymmetry in time trial position, Computer Methods in
Biomechanics and Biomedical Engineering, 20:sup1, 23-24, DOI: 10.1080/10255842.2017.1382842
To link to this article: http://dx.doi.org/10.1080/10255842.2017.1382842
© 2017 The Author(s). Published by Informa
UK Limited, trading as Taylor & Francis
Group
Published online: 27 Oct 2017.
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COMPUTER METHODS IN BIOMECHANICS AND BIOMEDICAL ENGINEERING, 2017
VOL. 20, NO. S1, S23S24
https://doi.org/10.1080/10255842.2017.1382842
Acute eect of biomechanical foot orthotics on gross eciency in cyclists
aected by an anatomic asymmetry in time trial position
A.Bouilloda,b,c, M.Retalib,d, G.Soto-Romeroc,e, E. Brunetb, M.Frémeauxa, J.Cassiramea, J.Maillotb and F.Grappea,f
aEA4660, C3S Health - Sport Department, Sports University, Besancon, France; bFrench Cycling Federation, Saint Quentin en Yvelines, France;
cLAAS-CNRS, Université de Toulouse, CNRS, Toulouse, France; dPodiatry, Altkirch, France; eISIFC – Génie Biomédical, Besançon, France; fProfessional
Cycling Team FDJ, Moussy le Vieux, France
KEYWORDS Pelvis tilt; foot orthotics; gas exchanges; mechanical power; time trial
1. Introduction
Cyclist position on his bicycle and individual anthro-
pometric parameters are very important to optimise
pedalling biomechanics (Bini et al. 2011). Postural imbal-
ance can lead to increase joint stress in the lower limbs.
erefore, dierent methods are used to reduce these joint
stresses such as chiropractic, kinesio taping or the use of
foot orthotics. e latter seem to be of interest to reduce
parasitic movements during the pedalling cycle (e.g. pelvis
tilt) and to restore the symmetry of the movements, both
during the pushing and pulling phases of the pedal.
Hice et al. (1985) measured a signicant decrease
in oxygen consumption (VO2) and heart rate with foot
orthotics in laboratory. Moreover, Yang (2013) showed
that, when cycling with personal bicycle, the contribution
of foot orthotics had benecial eects on muscular activ-
ity of vastus medialis, vastus lateralis and gastrocnemius
medialis which are recruited during the pushing phase.
e activation time of those muscles decreases, which
leads to a decrease in muscular fatigue, while the peak
muscle power increases.
e scientic literature is controversial on the inu-
ence of foot orthotics in cycling. erefore, the aim of our
study was to analyse the acute eect of foot orthotics on
gross eciency (GE) and comfort in cyclists aected by
an anatomic asymmetry in TT position. We hypothesize
that foot orthotics could increase comfort and GE with a
decrease in VO
2
considering better stability on the saddle.
2. Methods
Twelve cyclists volunteered to participate in the study.
All participants were licensed to the French Cycling
Federation and were assigned into two groups, a test group
(TG; n=6) and a control group (CG; n=6) based on their
anatomic asymmetry. All participants gave their written
informed consents aer received full explanation of the
protocol.
e participants performed two 11-min testing ses-
sions separated by one hour (before and aer orthopaedic
correction) in TT position using their personal TT bicy-
cle xed on a Hammer Direct Drive Trainer (CycleOps,
Madison, USA) at three dierent intensities (3, 3.5 and
4W kg−1). Each intensity lasted 2min. ese intensities
were separated by 1min at 2W kg−1 whereas the rst
intensity was preceded by 3min at 2W kg−1. e pedal-
ling cadence was free during the rst testing session and
the cyclists had to reproduce the same pedalling cadence
and TT position during the second session.
All participants have been examined between the two
testing sessions 1) to detect a lower limb length inequal-
ity (LLLI) with current clinical assessments (Brady et al.
2003). Firstly, clinical exam on the table validates a LLLI
higher than 5mm. Secondly, standing clinical exam vali-
dates the pelvis tilt induced by the LLLI on the same side.
irdly, cycling clinical exam validates the pelvis tilt on
the saddle. e cyclists without pelvis tilt were included
in the CG and received no change for the second testing
session.e cyclists with the three signs of pelvis tilt are
included in the TG and received custom foot orthotics
molded under the feet with medial arch support and a
3 millimeters’ spacer under the shoes for the side of the
lower limb. e cyclists were aware of these changes.
e workload was automatically adjusted by the
Hammer Direct Drive Trainer via Vitual Training so-
ware and recorded on the same platform. Metabolic
measurements were done with a breath-by-breath device
(Metalyzer 3B-R3, Cortex, Leipzig, Germany). Metalyzer
© 2017 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 License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use,
distribution, and reproduction in any medium, provided the original work is properly cited.
CONTACT A. Bouillod anthonybouillod@gmail.com
OPEN ACCESS
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S24 A. BOUILLOD ET AL.
4. Conclusions
is study demonstrates a trend for biomechanical foot
orthotics to improve both the GE and comfort, which are
determinant in cycling performance. However, future
studies with a larger sample should investigate this topic
considering the individual responses measured.
Acknowledgements
e authors wish to thank the participating cyclists for their
cooperation and the Matsport Company for its material sup-
port.
References
Bini RR, Hume PA, Cro JL. 2011. Eects of bicycle saddle
height on knee injury risk and cycling performance. Sports
Med. 41:463–476.
Brady RJ, Dean JB, Skinner TM, Gross MT. 2003. Limb
length inequality: clinical implications for assessment and
intervention. J Orthop Sports Phys er. 33:221–234.
Hice G, Kendrick Z, Weeber K, Bray J. 1985. e eect of
foot orthoses on oxygen consumption while cycling. J Am
Podiatr Med Assoc. 75:513.
Moseley L, Jeukendrup AE. 2001. e reliability of cycling
eciency. Med Sci Sports Exercise. 33:621–627.
Yang S. 2013. e ecacy of arch support sports insoles in
increasing the cycling performance and injury prevention.
Footwear Sci. 5:S107–S109.
3B-R3 measures breathing ow through bi directional dig-
ital turbine and 2.2m sample line tube collect inspired
and expired air to measure O2 and CO2 concentrations.
O2 consumption (VO2, L min−1) and CO2 production
(VCO
2
, L min
−1
) were calculated using standard metabolic
algorithms. GE was calculated from measures of energy
expended (EE, J s−1) and mechanical power (PO) averaged
over the last minute of each intensity. As presented previ-
ously (Moseley and Jeukendrup 2001):
With EE = [(3.869×VO2) + (1.195×VCO2)] × [(4.186/60)
× 1000].
Finally, a visual analogue scale from 0 (very uncom-
fortable) to 10 (very comfortable) was used to assess the
comfort of fourteen dierent anatomical locations at the
end of each session: le and right feet, le and right lower
limbs, saddle, back, head, le and right upper limbs, le
and right elbows, le and right hands and general comfort.
All these data were averaged to obtain a unique comfort
rating.
e data of the three intensities were averaged and ana-
lyzed with a paired t-test. We used eect size (ES, Cohens
d) to estimate the magnitude of the dierence between the
two testing sessions in GE and comfort. e dierence was
considered trivial when ES≤0.2, small when ES≤0.5,
moderate when ES≤0.8, and large when ES>0.8.
3. Results and discussion
e Figure 1 shows that the mean GE did not change sig-
nicantly in the TG (+1.1%, p= 0.608 and ES=0.205)
aer the laying of the foot orthotics whereas it was a
tendency to decrease in the CG (-4.6%, p = 0.058 and
ES = 0.452). e decrease in GE in the CG could be
explained by fatigue.
Individual responses are measured in TG because three
participants increased their GE in the second session
while the other three decreased their GE. Moreover, the
perceived comfort did not change signicantly in both CG
(7.6 vs. 7.3, p=0.363 and ES=0.406) and TG (8.0 vs. 7.3,
p=0.102 and ES=0.478) in the second test. By consider-
ing the dierence between TG and CG, this study shows a
trend for which biomechanical foot orthotics, in cyclists
aected by a LLLI, slightly improve the GE (+5.7%) and
comfort (+4.5%) in TT position.
GE =PO ×100%∕EE
Figure 1. Scatterplot representing the acute effect of
biomechanical foot orthotics on gross efficiency (CG: control
group; TG: test group). Grey lines: individual values; black lines:
mean values.
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... However, to our knowledge, no study has evaluated their effects on hip, knee and ankle kinematics of the short lower limb while pedalling. The use of soles and spacers can improve gross efficiency (GE) [10] and comfort [10,11]. Spacers may also reduce the bilateral differences in joint kinematics (hip, knee, ankle), torque production and vastus lateralis activity between the two lower limbs in cyclists affected by a small lower limb length discrepancy (Mean ± SD 5.4 ± 2.9 mm) [9]. ...
... However, to our knowledge, no study has evaluated their effects on hip, knee and ankle kinematics of the short lower limb while pedalling. The use of soles and spacers can improve gross efficiency (GE) [10] and comfort [10,11]. Spacers may also reduce the bilateral differences in joint kinematics (hip, knee, ankle), torque production and vastus lateralis activity between the two lower limbs in cyclists affected by a small lower limb length discrepancy (Mean ± SD 5.4 ± 2.9 mm) [9]. ...
... Previous studies have also found that changing crank arm length does not influence metabolic variables [4,18]. However, it has been shown that foot orthotics could improve GE [10] and VȮ 2 [30]. Despite the changes in joint kinematics with asymmetrical cranks, these physiological variables were not affected in the current study, which is consistent with the results of Macdermid and Mann [9]. ...
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Incorrect bicycle configuration may predispose athletes to injury and reduce their cycling performance. There is disagreement within scientific and coaching communities regarding optimal configuration of bicycles for athletes. This review summarizes literature on methods for determining bicycle saddle height and the effects of bicycle saddle height on measures of cycling performance and lower limb injury risk. Peer-reviewed journals, books, theses and conference proceedings published since 1960 were searched using MEDLINE, Scopus, ISI Web of Knowledge, EBSCO and Google Scholar databases, resulting in 62 references being reviewed. Keywords searched included 'body positioning', 'saddle', 'posture, 'cycling' and 'injury'. The review revealed that methods for determining optimal saddle height are varied and not well established, and have been based on relationships between saddle height and lower limb length (Hamley and Thomas, trochanteric length, length from ischial tuberosity to floor, LeMond, heel methods) or a reference range of knee joint flexion. There is limited information on the effects of saddle height on lower limb injury risk (lower limb kinematics, knee joint forces and moments and muscle mechanics), but more information on the effects of saddle height on cycling performance (performance time, energy expenditure/oxygen uptake, power output, pedal force application). Increasing saddle height can cause increased shortening of the vastii muscle group, but no change in hamstring length. Length and velocity of contraction in the soleus seems to be more affected by saddle height than that in the gastrocnemius. The majority of evidence suggested that a 5% change in saddle height affected knee joint kinematics by 35% and moments by 16%. Patellofemoral compressive force seems to be inversely related to saddle height but the effects on tibiofemoral forces are uncertain. Changes of less than 4% in trochanteric length do not seem to affect injury risk or performance. The main limitations from the reported studies are that different methods have been employed for determining saddle height, small sample sizes have been used, cyclists with low levels of expertise have mostly been evaluated and different outcome variables have been measured. Given that the occurrence of overuse knee joint pain is 50% in cyclists, future studies may focus on how saddle height can be optimized to improve cycling performance and reduce knee joint forces to reduce lower limb injury risk. On the basis of the conflicting evidence on the effects of saddle height changes on performance and lower limb injury risk in cycling, we suggest the saddle height may be set using the knee flexion angle method (25-30°) to reduce the risk of knee injuries and to minimize oxygen uptake.
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