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Is economy of competitive cyclists affected by the anterior-posterior foot position on the pedal?

Authors:

Abstract

The primary purpose of this investigation was to test the hypothesis that cycling economy, as measured by rate of oxygen consumption (VO(2)) in healthy, young, competitive cyclists pedaling at a constant workrate, increases (i.e. VO(2) decreases) when the attachment point of the foot to the pedal is moved posteriorly on the foot. The VO(2) of 11 competitive cyclists (age 26.8+/-8.9 years) was evaluated on three separate days with three anterior-posterior attachment points of the foot to the pedal (forward=traditional; rear=cleat halfway between the head of the first metatarsal and the posterior end of the calcaneous; and mid=halfway between the rear and forward positions) on each day. With a randomly selected foot position, VO(2) was measured as each cyclist pedaled at steady state with a cadence of 90 rpm and with a power output corresponding to approximately 90% of their ventilatory threshold (VT) (mean power output 203.3+/-20.8 W). After heart rate returned to baseline, VO(2) was measured again as the subject pedaled with a different anterior-posterior foot position, followed by another rest period and then VO(2) was measured at the final foot position. The key finding of this investigation was that VO(2) was not affected by the anterior-posterior foot position either for the group (p=0.311) or for any individual subject (p>or=0.156). The VO(2) for the group was 2705+/-324, 2696+/-337, and 2747+/-297 ml/min for the forward, mid, and rear foot positions, respectively. The practical implication of these findings is that adjusting the anterior-posterior foot position on the pedal does not affect cycling economy in competitive cyclists pedaling at a steady-state power output eliciting approximately 90% of VT.
Journal of Biomechanics 40 (2007) 1262–1267
Is economy of competitive cyclists affected by the anterior–posterior
foot position on the pedal?
J.R. Van Sickle Jr
a
, M.L. Hull
a,b,
a
Biomedical Engineering Graduate Group, One Shields Avenue, University of California, Davis, CA 95616, USA
b
Department of Mechanical Engineering, One Shields Avenue, University of California, Davis, CA 95616, USA
Accepted 29 May 2006
Abstract
The primary purpose of this investigation was to test the hypothesis that cycling economy, as measured by rate of oxygen
consumption ð_
VO2Þin healthy, young, competitive cyclists pedaling at a constant workrate, increases (i.e. _
VO2decreases) when the
attachment point of the foot to the pedal is moved posteriorly on the foot. The _
VO2of 11 competitive cyclists (age 26.878.9 years)
was evaluated on three separate days with three anterior–posterior attachment points of the foot to the pedal (forward ¼traditional;
rear ¼cleat halfway between the head of the first metatarsal and the posterior end of the calcaneous; and mid ¼halfway between
the rear and forward positions) on each day. With a randomly selected foot position, _
VO2was measured as each cyclist pedaled at
steady state with a cadence of 90 rpm and with a power output corresponding to approximately 90% of their ventilatory threshold
(VT) (mean power output 203.3720.8 W). After heart rate returned to baseline, _
VO2was measured again as the subject pedaled
with a different anterior–posterior foot position, followed by another rest period and then _
VO2was measured at the final foot
position. The key finding of this investigation was that _
VO2was not affected by the anterior–posterior foot position either for the
group (p¼0:311) or for any individual subject (pX0.156). The _
VO2for the group was 27057324, 26967337, and 27477297 ml/
min for the forward, mid, and rear foot positions, respectively. The practical implication of these findings is that adjusting the
anterior–posterior foot position on the pedal does not affect cycling economy in competitive cyclists pedaling at a steady-state power
output eliciting approximately 90% of VT.
r2006 Elsevier Ltd. All rights reserved.
Keywords: Economy; Energy expenditure; Efficiency; Oxygen consumption; Ankle; Plantar flexor; Triceps surae; Muscle
1. Introduction
The two most important physiological factors in
determining a rider’s maximum average power output,
and therefore velocity, are the rider’s cycling economy
and the rider’s _
VO2at lactate threshold (Coyle, 1995).
Economy is defined as the caloric energy expenditure at
a given workrate. At a given workrate, economy is a
useful indicator of the gross efficiency defined as the
ratio of the work accomplished per unit time to the
caloric energy expenditure per unit time. Economy is
dictated by the energy demands placed on the rider,
which in turn are dictated by the force demands required
of the muscles. Reducing the muscular forces at a given
power output may translate into improvements in
performance (Coyle, 1995).
One means for decreasing the force developed by the
ankle plantarflexors is to move the foot on the pedal
anteriorly. By equilibrating the moment about the ankle
joint created by the pedal reaction force, the ankle
plantarflexors act primarily to transfer the power
produced by the hip and knee extensors to the crank
(Raasch et al., 1997;Zajac et al., 2002) and hence
contract largely isometrically. The force developed by
the plantarflexors to transfer this power is substantial.
For example, at a crank angle of 901(i.e. crank
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0021-9290/$ - see front matter r2006 Elsevier Ltd. All rights reserved.
doi:10.1016/j.jbiomech.2006.05.026
Corresponding author. Tel.: +1 530 752 6220;
fax: +1 530 752 4158.
E-mail address: mlhull@ucdavis.edu (M.L. Hull).
horizontal and forwards), the equilibrating force in the
Achilles tendon for a size 9 ft in the traditional anterior–
posterior position while pedaling at 90 rpm and 250 W is
approximately 650 N. Consequently, moving the cleat
rearward on the shoe would move the foot anteriorly on
the pedal thus reducing the moment developed by the
pedal reaction load about the ankle joint (Ericson et al.,
1985b;Gonzalez and Hull, 1989) and decreasing the
force required by the ankle plantarflexors to equilibrate
this moment (Ericson et al., 1985a;van Sickle, 2003).
This reduction in force could translate into an increase
in economy. Because the effect of anterior–posterior
foot position on economy in cycling is unknown, the
primary objective of this study was to test the hypothesis
that gross metabolic energy expenditure as indicated by
_
VO2in competitive cyclists decreases when the attach-
ment point of the foot to the pedal is moved posteriorly
on the foot. If the gross metabolic energy expenditure is
not affected for the competitive cycling population, then
a second objective was to determine whether effects are
evident for individual subjects. This latter objective was
of interest because pedaling mechanics differ between
subjects (Coyle et al., 1991) so that the energy
expenditure of individual subjects might be affected
even if energy expenditure of the population was not.
2. Methods
Eleven subjects, nine males and two females, were
recruited from the local cycling community (Table 1).
All subjects had a minimum of 2 years of competition,
and 4 years cycling experience; their average age was 26
years.
After obtaining approval of the experimental protocol
by the Institutional Review Board and after obtaining
written informed consent of each subject, all testing was
performed using a bicycle (Model 1500, Trek, Madison,
WI) mounted on a Velodyne cycling ergometer (Front-
line Technology, Irvine, CA). The Velodyne ergometer
provided constant power outputs that could be adjusted
incrementally and maintained independent of pedaling
rate. The test bicycle was adjusted to match the
dimensions of the subject’s own bicycle. The dimensions
measured for this purpose included the following: (1)
seat height, (2) knee over pedal spindle (seat fore-aft
position), (3) stem height (in relation to seat), and (4)
nose of saddle to handlebar clamp distance.
To modulate the force demand of the ankle plantar-
flexors, the cleat was mounted in three different
anterior–posterior positions. The traditional, or for-
ward, position with the cleat beneath the head of the
first metatarsal was used as a baseline reference. The
other two positions were the rear position, halfway
between the head of the first metatarsal and the
posterior end of the calcaneous, and a mid position,
halfway between the rear and forward positions. The
progressive rearward mounting of the look-style cleat
was accomplished by mounting the cleat on a light-
weight (135 g), longitudinally slotted plate affixed to the
bottom of lightweight (650 g for size 43) cycling shoes
(SH-R100, Shimano, Irvine, CA). Because the effective
leg length was decreased for the more rearward cleat
positions, the seat height was necessarily lowered so that
the subjects could reach the pedals. The seat height and
handlebar heights were lowered by the amounts
necessary to maintain the same patterns of motion
(measured using a video-based motion analysis system)
for the hip and knee for each foot position for each
subject.
2.1. Experimental design
All testing was performed at a power output designed
to elicit approximately 90% of the rate of oxygen
consumption associated with ventilatory threshold (VT)
of each of the 11 competitive cyclists who volunteered to
be test subjects. VT was used instead of a strict
percentage of _
VO2 max because VT is a better predictor
of athletic performance (Coyle, 1995). VT provides a
reference for the metabolic pathways being used by the
body (i.e. right at the beginning of an exponential
increase in arterial CO
2
pressure, which is PaCO
2
)
(Coyle, 1995). Accordingly, each subject worked at
approximately the same relative level of effort. VT was
determined using gas exchange and the ‘‘V-slope’’
method (Wasserman et al., 1994). The protocol involved
breath-by-breath measurement of _
VCO2, plotted
against the simultaneous _
VO2(Physio-Dyne Max-1,
Physio-Dyne Instruments Corp., Quogue, NY).
The VT test was designed to take approximately
14 min (Wasserman et al., 1994). The subjects began by
riding for 3 min at 100 W. The loading was incremen-
tally increased 25 W/min either for the next 12 min to
elicit a respiratory exchange ratio ðRER ¼_
VCO2=_
VO2Þ
of at least 1.1 or until the subject could no longer
continue. The power output needed to elicit a _
VO2of
ARTICLE IN PRESS
Table 1
Subject data
Subject Gender Age (years) Height (m) Weight (kg) Level
Subject 1 M 24 1.816 74.9 Cat 2
Subject 2 M 22 1.803 69.9 Cat 4
Subject 3 M 50 1.765 79.9 Mas 45+
Subject 4 M 36 1.854 78.1 Cat 3
Subject 5 F 21 1.702 59.9 Cat 3
Subject 6 M 21 1.778 83.1 Cat 4
Subject 7 M 22 1.753 74.9 Cat 4
Subject 8 M 22 1.880 87.2 Cat 4
Subject 9 F 22 1.778 64.5 Cat 3
Subject 10 M 27 1.867 79.9 Cat 3
Subject 11 M 28 1.854 78.1 Cat 4
J.R. Van Sickle Jr, M.L. Hull / Journal of Biomechanics 40 (2007) 1262–1267 1263
approximately 90% of each subject’s VT was deter-
mined.
Subsequent to the VT test, the subjects were tested in
the different foot positions on each of 3 days to reduce
the standard error in _
VO2measurements and test days
were spaced during a period of 2 weeks to reduce any
effects of concurrent training. The testing of each
subject occurred at a regular time of day within a 2-h
window to control for any effect of the time of day on
test results (Hill et al., 1992;Hill, 1996). All foot
positions were tested each day, keeping the protocol
identical and randomizing the foot position order. On
each day preceding a test day, the subjects rested from
their regular training regimen so that fatigue as a result
of training load immediately prior to the test day did not
affect test results (Sherman et al., 1984). The order of the
foot positions was randomized for each subject to
minimize any carry over effects.
The testing each day began by measuring the subject’s
resting heart rate in a sitting position after allowing the
subject to rest comfortably for 5 min. The subject then
warmed up for 17 min with the foot in the forward
position. The warm up consisted of 10 min at 125 W,
5 min at 90% VT, and 2 min at 100 W. The entire warm
up was ridden at 90 rpm. A metronome, as well as a
visual cadence indicator, was used to regulate the
cadence. Following the warm up, the subject was
allowed to recover until their heart rate returned to
within 20 beats per minute (bpm) of the previously
measured resting value. To allow for adaptation to the
different foot positions, each subject then rode for
10 min at 125 W and 90 rpm under each position to be
tested. Upon completion of the adaptation period, the
subject was allowed to recover until their heart rate fell
to within 20 bpm of their resting value. The subject then
began pedaling at 125 W and 90 rpm, and the resistance
was steadily increased over 1 min up to the power output
corresponding to approximately 90% of their VT for the
forward foot position. The subject continued riding for
7 min at 90% of their VT and 90 rpm. Data were
collected for the last 3 min of the interval while the
subject was at steady state (Riley and Cooper, 2002).
After the subject’s heart rate fell to within 20 bpm of
their resting value, the next randomly selected foot
position was tested.
2.2. Energy expenditure measurement and data analysis
Oxygen uptake was determined using open-circuit
metabolic procedures. Expired gasses were collected
using a triple-J valve with mouthpiece, and analyzed for
volume and concentration using a metabolic gas
analyzer. _
VO2was calculated from breath-by-breath
collection with averages over each minute. The averaged
value from the last 3 min of each trial was used to
minimize variability.
To address the two objectives of the study, statistical
analyses were performed. To test the hypothesis that
moving the cleat rearward on the pedal decreased _
VO2
for the competitive cycling population, a one-factor
repeated measures ANOVA on repeated observations
for all subjects was used. To determine whether moving
the cleat rearward on the pedal decreased _
VO2for
individual subjects, a one-factor ANOVA on repeated
observations for each subject was used. In each of these
analyses, the single factor was the anterior–posterior
foot position at three levels (forward, mid, and rear) and
the dependent variable was _
VO2averaged over the last
3 min of each trial. If significant effects were detected
(po0:05), then a post hoc Tukey pairwise comparison
was used to identify which foot positions significantly
affected _
VO2. SAS (Release 8.02, Cary, NC) was used
for all statistical calculations.
3. Results
The foot position did not significantly affect _
VO2for
the sample of subjects tested (p¼0:311) (Table 2).
Indeed the differences in the _
VO2averaged over all of
the subjects for the mid and rear positions from the
forward position were small (Fig. 1). The average
difference in _
VO2between the mid and forward
positions was only 10 ml/min or 0.4% relative to the
forward position. The average difference in _
VO2
between the rear and forward positions was greater
than that between the mid and forward positions but
was still limited to only 41 ml/min or 1.5% relative to
the forward position (Fig. 1).
When the data were analyzed on a per subject basis,
the foot position did not significantly affect _
VO2for any
of the subjects (p40:156). Only three of the 11 subjects
(subjects 1, 6, 10) showed a consistent trend in _
VO2with
foot position when averaged over the 3 days but these
trends were not strong enough to be significant
statistically.
4. Discussion
Improving cycling economy through biomechanical
modifications of the bicycle-rider interface is a potential
means for improving athletic performance. Changing
the anterior–posterior foot position on the pedal had the
potential to alter a rider’s economy by substantially
reducing the force of the ankle plantarflexors. The
hypothesis tested in this study was that the gross
metabolic energy expenditure of the cyclist would
decrease when the attachment point of the foot to the
pedal was moved posteriorly on the foot. The key
findings were that _
VO2for the rear and mid foot
positions was not significantly different from that of the
ARTICLE IN PRESS
J.R. Van Sickle Jr, M.L. Hull / Journal of Biomechanics 40 (2007) 1262–12671264
forward position for either the subject sample or for any
individual subjects.
Because the null hypothesis was not rejected and
because a small 1.5% difference in _
VO2between the
forward and rear positions existed for the subject sample
which could translate into a performance difference, a
post hoc power analysis based on the variability in the
data collected and the small difference observed was
conducted. In this analysis, the difference to detect,
delta, was set at 41 ml O
2
/min and the sample standard
deviation, sigma (i.e. square root of the error term), was
equal to 59 ml O
2
/min. For a delta/sigma ratio ¼0.7, the
power of the statistical test was approximately 95%
which indicates that there is a low probability of falsely
accepting the null hypothesis. Accordingly, the null
hypothesis that there is no difference in _
VO2can be
accepted with high confidence.
The results did not support the hypothesis notwith-
standing the substantial decreases in the force demand
placed on the ankle plantarflexors by moving the cleat
posteriorly to the mid and rear positions. At constant
power output, the intersegmental moment developed at
the ankle joint is proportional to the distance between
the attachment point of the shoe to the pedal and the
ankle joint (Ericson et al., 1985b). Because only the
ankle plantarflexors but not the dorsiflexors are active
when the ankle intersegmental moment is maximum
(Neptune et al., 1997), the corresponding force produced
by the ankle plantarflexors is modulated in direct
proportion to changes in the intersegmental ankle
moment. The ankle intersegmental moment and hence
force demand on the ankle plantarflexors decreased by
approximately 30% and 65% for the mid and rear foot
positions, respectively.
Because the results did not support the hypothesis, it
is of interest to consider the implications to the
mechanical kinetics of the muscles. Although the ankle
plantarflexors act primarily to transfer the power
produced by the hip and knee extensors to the crank
(Raasch et al., 1997;Zajac et al., 2002), they also
generate power in their own right contributing about
7.5% of the total work to complete one crank cycle
(Zajac et al., 2002). Moving the cleat posteriorly on the
foot not only reduced the force demand on the ankle
plantarflexors to equilibrate the ankle joint moment
developed by the foot-pedal reaction forces, but also
reduced the ability of the ankle plantarflexors to
generate power. Because the average power generated
by the subjects was maintained constant, another
muscle(s) would have to generate additional power to
compensate for the loss in power of the ankle plantar-
flexors. Accordingly one possible explanation of the
result in this study is that the increase in energy
expenditure to redistribute power to another muscle(s)
was equal to the loss in energy expenditure accompany-
ing the reduced force of the ankle plantarflexors.
ARTICLE IN PRESS
Table 2
Rates of oxygen consumption for each subject (ml O
2
/min)
Day Forward Mid Rear
Subject 1 1 3044 3003 2967
2 3048 3093 3079
3 3040 3027 3045
Subject 2 1 2737 2752 2722
2 2559 2575 2554
3 2774 2889 2829
Subject 3 1 2816 2953 2831
2 3112 3075 3063
3 2597 2543 2458
Subject 4 1 3159 3137 3142
2 3109 3083 3114
3 2812 2836 2822
Subject 5 1 2337 2281 2320
2 2449 2424 2450
3 2035 2002 2953
Subject 6 1 2860 2940 3035
2 3003 2815 2963
3 2926 2909 2926
Subject 7 1 2708 2582 2700
2 2477 2424 2471
3 2693 2738 2762
Subject 8 1 3006 2993 2973
2 2871 2792 2840
3 2721 2814 2844
Subject 9 1 2180 2112 2210
2 2186 2157 2210
3 1986 1968 1995
Subject 10 1 2920 2980 3030
2 3061 3024 3111
3 2990 3002 3080
Subject 11 1 2343 2343 2338
2 2374 2374 2422
3 2357 2329 2380
2747
2696
2706
1500
2000
2500
3000
3500
Forward Mid Rear
Foot Position
Rate of Oxygen Consumption
(ml/min)
Fig. 1. Bar graph illustrating average rates of oxygen consumption
across all subjects for the three foot positions. The error bars are 71
standard deviation. The foot position did not significantly affect the
rate of oxygen consumption (p¼0:311).
J.R. Van Sickle Jr, M.L. Hull / Journal of Biomechanics 40 (2007) 1262–1267 1265
In considering which muscles are likely to provide the
additional power, the principal candidates are the
gluteus maximus and/or the vastii because these muscles
produce the majority of the power in the downstroke
region of the crank cycle and because the ankle
plantarflexors act synergistically with the hip and knee
extensors to transfer power to the crank (Raasch et al.,
1997;Zajac et al., 2002). In an effort to determine which
of these muscles provided the extra power, the electro-
myograms of the vastus lateralis, vastus medialis, and
gluteus maximus were recorded with surface electrodes
during the experiments (van Sickle, 2003). The methods
and results of these measurements are summarized
briefly below and are not presented in greater detail
because the measurements were not central to test the
hypothesis of the study and because the results were
inconclusive. The activation of each muscle was
computed as described previously (Raasch et al., 1997;
Neptune and Hull, 1998) and it can be argued that the
activation was a relative indicator of the muscle force
for the conditions of these experiments (van Sickle,
2003). The activation was analyzed statistically using a
single-factor repeated measures ANOVA where the
independent variable was foot position at three levels
and the dependent variable was the activation integrated
over the crank cycle. There was no statistically
significant increase in integrated activation for any of
the muscles as the cleat position was moved posteriorly
on the sole of the shoe (p40:05). An increase in
activation may not have been detected because other
muscles, which could not be monitored with surface
electrodes, provided the additional power. For example,
the vastus intermedius could have provided most of the
additional power because it contributes the greatest to
knee extension moment of the three vastii muscles
(Zhang et al., 2003). Alternatively the additional power
could have been distributed to either one or more of the
muscles that were monitored but the increase was
difficult to detect using activation computed from
surface electromyography.
To confirm the large decrease in plantarflexor force of
approximately 30% and 65% for the mid and rear
positions expected from the equilibrium analysis, the
electromyograms also were recorded for the three ankle
plantarflexors (van Sickle, 2003). The integrated activa-
tion over the crank cycle for the mid and rear positions
decreased by 27% and 54%, respectively, compared to
the forward position and these decreases were statisti-
cally significant (po0:0001) (van Sickle, 2003). The
dramatic decreases in integrated activation support the
results from equilibrium that the force demand on the
ankle plantarflexors was substantially decreased.
The result that the anterior–posterior foot position
had a minimal effect on the economy in pedaling has an
important practical implication. Many commercially
available cycling shoes offer a small (71 cm) range of
adjustment of the anterior–posterior cleat position and
this range could be readily increased if such an increase
is warranted. Based on the results of this study however,
there is no economy advantage to be gained in terms of
energy cost by adjusting the anterior–posterior cleat
position for cyclists riding at approximately 90% VT at
a steady-state pedaling rate of 90 rpm.
Lowering the force demand of the ankle plantarflex-
ors could be beneficial to injured athletes. For athletes
with injuries to either the Achilles tendon or the muscles
in the triceps surae group, it would be beneficial to
reduce the load on this muscle–tendon complex while
maintaining the ability to either exercise or possibly
compete. Because a significant change in energy
expenditure was not demonstrated for a more rearward
cleat position, a more rearward position can be adopted
without an expected decrease in steady-state perfor-
mance due to increased energy expenditure.
Two biomechanical variables that were controlled so
that they did not systematically affect the metabolic
energy expenditure were the seat height and the
handlebar height. Seat height was adjusted (i.e. lowered)
as the cleat position was moved posteriorly on the sole
of the shoe. Subjects could not reach the pedals at the
bottom of the crank cycle with the posterior cleat
positions because the effective length of the leg
decreased due to the loss in foot length as the cleat
position was moved posteriorly on the sole of the shoe.
The seat was lowered for the mid position by 7 mm on
average and for the rear position by 13 mm on average.
The handlebar height was also lowered in conjunction
with the seat height. These two adjustments served to
maintain the patterns of motion of both the hip and
knee constant as verified through motion analysis.
Without maintaining the joint patterns of motion
constant, the experiment design could have been
confounded because changes in both anterior–posterior
foot position and joint patterns of motion could have
affected the energy expenditure (Shennum and deVries,
1976;Nordeen-Snyder, 1977;Grappe et al., 1998). Thus
to isolate the anterior–posterior foot position as a single
independent variable for study, the physical seat height
and handlebar height were adjusted to maintain a
constant ‘effective’ seat height.
In summary, the anterior–posterior foot position did
not affect pedaling economy both for the population of
competitive cyclists and for individuals within this
population. Thus the substantial decrease in the force
of the ankle plantarflexors that occurred when the cleat
position was moved posteriorly on the sole of the shoe
did not elicit a change in economy for steady-state
cycling. From a cycling performance standpoint, there is
no benefit in moving the cleat posteriorly on the sole of
the shoe. From a clinical standpoint, the anterior–
posterior foot position can be adjusted to lower the
force transmitted through the Achilles tendon while
ARTICLE IN PRESS
J.R. Van Sickle Jr, M.L. Hull / Journal of Biomechanics 40 (2007) 1262–12671266
minimally affecting the patient’s ability to exercise,
which may be beneficial to injured athletes.
Acknowledgement
The authors are grateful to Professor James Shaffrath
of the Department of Exercise Biology for advice on the
experimental design and measurement of human per-
formance variables.
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ARTICLE IN PRESS
J.R. Van Sickle Jr, M.L. Hull / Journal of Biomechanics 40 (2007) 1262–1267 1267
... Several studies evaluated the effect of the change in the antero-posterior shoe-cleat placement on cycling economy during a constant or a non-constant power output pedalling trial, but none of them have found significant changes in heart rate or oxygen consumption (Millour et al., 2020;Paton, 2009;Paton & Jardine, 2012;Van Sickle & Hull, 2007;Viker & Richardson, 2013). Nevertheless, several studies (Ericson et al., 1985;Litzenberger et al., 2008;McDaniel & Fu, 2013;Millour et al., 2020) found that moving the cleat posterior to the first metatarsal position during submaximal intensity reduced the surface electromyographic activity (EMG) of ankle plantar flexors muscles (i.e., Gastrocnemius Medialis and Soleus) and increased EMG of ankle dorsiflexors (i.e., Tibialis Anterior) and hip flexors (i.e., Rectus Femoris). ...
... Although some of these previous research provided interesting findings, most of them have studied larger shoe-cleat position changes (i.e., around ± 50 mm), which are well beyond the range of fore-aft adjustment range possible (10 to 15 mm) with commercially available road cycling shoes (Millour et al., 2020). On the other hand, only two of the abovementioned studies were conducted in experienced cyclists (Paton, 2009;Van Sickle & Hull, 2007), and none of them evaluated the pedalling biomechanics. Moreover, no study has compared both anterior and posterior shoe-cleat positions with respect to the reference position (i.e., the first metatarsal head). ...
... As expected from previous studies (Paton, 2009;Paton & Jardine, 2012;Van Sickle & Hull, 2007;Viker & Richardson, 2013), lower limb extension (hip, knee, and ankle joint angles) increased with the posterior cleat position. The knee extensions observed in this study were within the recommended range (140-150°) for minimising the risk of overuse injuries (Ferrer-Roca et al., 2014, 2017. ...
Article
The aim of this study was to investigate the effect of changes in cycling shoe-cleat position on pedalling biomechanics, physiological variables, and performance in road cycling. Twelve competitive road cyclists performed three pedalling trials with the cleat positioned at the first metatarsal head, 15-mm anterior and 15-mm posterior. Each trial included three sets of 5 min performed at 35%, 50%, and 65% of maximal aerobic power (MAP) followed by a 10-s sprint. Results showed no significant changes in physiological variables, pedalling kinetics, muscular activity of six lower limb muscles, sprint performance and perceived exertion. However, significant differences were found regarding joint kinematics: hip, knee, and ankle angles during both extension and flexion were reduced in the anterior cleat position. Therefore, this study suggests that cleat position does not affect sprint performance, physiological variables, pedalling kinetics, muscle activity, and perceived exertion regardless of the cycling intensity. However, joint kinematics, and particularly knee extension angle which could be related to the risk of overuse injuries, was affected by the shoe-cleat position.
... In this instance, the first metatarsal head is positioned directly above the pedal spindle (i.e., fore-aft) [17,18]. However, despite this location being suggested to be the most optimal for performance, it is controversial [19], not well investigated and may promote a higher likelihood for injury [20]. Whereas the MPJ region appears to have been adopted by a significant array of cyclists, it remains largely theoretical whether the location is beneficial for triathletes given the run segment that follows. ...
... Furthermore, the variations of trunk acceleration occurred in the longitudinal direction with nominal increases seen in mediolateral motion. Despite prior studies confirming a beneficial effect of antero-posterior (i.e., MPJ-POS) cleat placement on physiological variables in running [4,14,19], few studies have assessed the temporal kinematics of the trunk and the corresponding impact of cycling and running. This makes direct comparisons with the results presented in this study difficult. ...
Article
Full-text available
Appropriate cycling cleat adjustment could improve triathlon performance in both cycling and running. Prior recommendations regarding cleat adjustment have comprised aligning the first metatarsal head above the pedal spindle or somewhat forward. However, contemporary research has questioned this approach in triathlons due to the need to run immediately after cycling. Subsequently, moving the pedal cleat posteriorly could be more appropriate. This study evaluated the effectiveness of a triaxial accelerometer to determine acceleration magnitudes of the trunk in outdoor cycling in two different bicycle cleat positions and the consequential impact on trunk acceleration during running. Seven recreational triathletes performed a 20 km cycle and a 5 km run using their own triathlon bicycle complete with aerodynamic bars and gearing. Interpretation of data was evaluated based on cadence changes whilst triathletes cycled in an aerodynamic position in two cleat positions immediately followed by a self-paced overground run. The evaluation of accelerometer-derived data within a characteristic overground setting suggests a significant increase in total trunk acceleration magnitude during cycling with a posterior cleat with significant increases to longitudinal acceleration (p = 0.04) despite a small effect (d = 0.2) to the ratings of perceived exertion (RPE). Cycling with a posterior cleat significantly reduced longitudinal trunk acceleration in running and overall acceleration magnitudes (p < 0.0001) with a large effect size (d = 0.9) and a significant reduction in RPE (p = 0.02). In addition, running after cycling in a posterior cleat was faster compared to running after cycling in a standard cleat location. Practically, the magnitude of trunk acceleration during cycling in a posterior cleat position as well as running after posterior cleat cycling differed from that when cycling in the fore-aft position followed by running. Therefore, the notion that running varies after cycling is not merely an individual athlete’s perception, but a valid observation that can be modified when cleat position is altered. Training specifically with a posterior cleat in cycling might improve running performance when trunk accelerations are analysed.
... Cycle racing is one of the few sports where performance is ascertained by physical output in direct contact with a mechanical device, and as a result, much work has gone into understanding the factors that affect the bicycle and the cyclist in a bid to create the most mechanically efficient model across disciplines. One area which has received lots of attention is the crank-pedal interface and how factors such as crank length (Martin and Spirduso, 2001;Barratt et al., 2016) and anterior-posterior foot position on the pedal (Van Sickle and Hull, 2007) can affect cycling performance. Another consideration has been the design of non-circular chainrings as a replacement of traditional circular chainrings in a bid to optimise cycling performance and/or efficiency (Hull et al., 1991;Hue et al., 2001;O'Hara et al., 2012). ...
... Since the invention of the derailleur in 1905, and consequently the ability to change gears, the mechanics of the drivetrain has remained relatively unchanged. However, there remains apparent constraints with the transfer of power from the body to the drivetrain, which are reliant upon a series of components such as crank length (Martin and Spirduso, 2001; Barratt et al., 2016), anterior-posterior foot position on the pedal (Van Sickle and Hull, 2007), seat height (Sanderson and Amoroso, 2009) and seat tube angle (Verma et al., 2016). All of these factors are responsible for affecting the moment about the ankle and/or hip, and ultimately the ability to apply maximum effective force. ...
Thesis
Full-text available
Optimisation of movement strategies during cycling is an area which has gathered a lot of attention over the past decade. Resolutions to augment performance have involved manipulations of bicycle mechanics, including chainring geometries. Elliptical chainrings are proposed to provide a greater effective diameter during the downstroke, manipulating mechanical leverage and resulting in greater power production during this period. A review of the literature indicates that there is a pervasive gap in our understanding of how the theoretical underpinnings of elliptical chainrings might be translated to practical use. Despite reasonable theory of how these chainrings might enforce a variation in crank angular velocity and consequently alter force production, performance-based analyses have struggled to present evidence of this. The purpose of this thesis was to provide a novel approach to this problem by combining experimental data with musculoskeletal modelling and evaluating how elliptical chainrings might influence crank reactive forces, joint kinematics, muscle-tendon unit behaviour and muscle activation. One main study was proposed to execute this analysis, and an anatomically constrained model was subsequently used to determine the joint kinematics and muscle-tendon unit behaviour. Bespoke elliptical chainrings were designed for this study and as such, different levels of chainring eccentricity (i.e. ratio of major to minor axis) and positioning against the crank were presented whilst controlling the influence of other variables known to affect the neuromuscular system such as cadence and load. Findings presented in this thesis makes a new and major contribution in our understanding of the neuromusculoskeletal adaptations which occur when using elliptical chainrings, showing alterations in crank reaction force, muscle-tendon unit velocities, joint kinematics and muscle excitation over a range of cadences and loads, and provides direction for where the future of this research might be best applied. Keywords: Elliptical chainrings; Cycling; Musculoskeletal modelling; Principal Component Analysis; Electromyography
... The economical transfer of power from the human body to mechanical power output driving the bicycle is influenced by many aspects of equipment configuration and the pacing strategy employed. Accordingly, manipulations of seat height [5,6], seat-tube angle, pedal cadence [7], chainring design [8,9], crank length [10,11], and the pedal design [1, 10,12] have all been investigated. ...
... Increasing the length of the crank arm during the downward stroke of the cycle has been shown to produce the highest torque values [15] and has subsequently lead to the design of non-circular chainrings to theoretically achieve such an effect. Nonetheless, the results of the experimental studies to date that have used such an approach could best be described as equivocal [8,11]. ...
Technical Report
Full-text available
The aim of both studies was to assess the effects of the EasyPedal prototypes compared to conventional pedals on cycling efficiency. The main study and case study results do not indicate reduced energy expenditure when using the EasyPedal prototypes versus conventional pedals in either a typical cycling set-up or semi-recumbant position. This is based on similar levels of oxygen consumption and heart rate when using both pedal types at the same absolute cycling intensity (measured in watts. However, this does not rule out a potential benefit of the EasyPedal prototype when used at slower cycling cadences (testing in this study carried out at cadences of approximately 70 rpm) or with a novel/alternative cycling pattern. The testing detailed in this report illustrates the acute responses to using these pedal prototypes (i.e. after < 30 minutes of use). It is possible that individuals could learn to perform an altered pedalling style which could make greater use of the potential mechanical advantages of the EasyPedal prototypes. Such an altered style would take time to develop and would change the neuromuscular requirements of the task. It is still unknown how much time would be required to develop such a pattern and what possible advantages it would provide in terms of cycling efficiency
... However, several cycling factors have been identified to play a key role for the subsequent running performance: cycling pacing strategy (Hausswirth et al. 1999 This adjustment, also based on empirical knowledge, could improve foot stability, due to a reduction in the lever arm of the foot (pedal axis to ankle joint), and reduce risk of Achilles tendon injury (Burt 2014). Some studies have found no significant impact of very large antero-posterior cleat displacements (≈ 5 cm) on physiological and performance variables during sub-maximal pedalling (Paton 2009, Van Sickle andHull 2007). However, no studies have assessed the impact of small changes of cleat position (< 1.5 cm) at intermittent intensities. ...
Article
Proper cleat adjustment improves cycling performance and prevents knee injuries. Recommendations have included positioning the first metatarsal head above the pedal spindle or slightly forward, but mid-foot cleat positions could be more appropriate in triathlons at constant load for their impact on the subsequent running performance. We evaluated the impact of antero-posterior cleat position on biomechanical and physiological variables during the cycling and running parts of a simulated Sprint triathlon. Seven participants performed two 32-min cycling tests including 8 sets of 3 min 30 s intervals performed at just below the power output at the first ventilatory threshold interspersed with 30 s sprints at > 100% of the maximal aerobic power. The cycling exercises were immediately followed by a maximal running performance of 20 min. The tests were performed with a 5-mm backward (BCP) and a 5-mm forward (FCP) first metatarsal cleat position. The BCP decreased the energetic cost during running (5.9%; p = 0.04; effect size [ES] = 0.92) despite no significant performance change in the cycling or the subsequent running tests. Moreover, the BCP resulted in a lower soleus recruitment during sub-maximal intensity (7.0%; p < 0.05; ES = 1.23) and of the gastrocnemius medialis (25.0%; ES = 1.00; p < 0.05) and tibialis anterior (11.9%; ES = 1.51) during the subsequent running. However, we observed much higher recruitment of the soleus (8.8%; ES = 1.36), vastus lateralis (10.1%; ES = 1.37), biceps femoris (12.0%; ES = 1.45), tibialis anterior (16.4%; ES = 3.35), and overall lower limb (11%; ES = 0.92) during sprints with the BCP. Therefore, the BCP could be more suitable in triathlons by being more economical for subsequent running despite the greater muscle activity during the cycling sprints, which form an important part of the cycling portion of Sprint triathlons.
... However, several cycling factors have been identified to play a key role for the subsequent running performance: cycling pacing strategy (Hausswirth et al. 1999 This adjustment, also based on empirical knowledge, could improve foot stability, due to a reduction in the lever arm of the foot (pedal axis to ankle joint), and reduce risk of Achilles tendon injury (Burt 2014). Some studies have found no significant impact of very large antero-posterior cleat displacements (≈ 5 cm) on physiological and performance variables during sub-maximal pedalling (Paton 2009, Van Sickle andHull 2007). However, no studies have assessed the impact of small changes of cleat position (< 1.5 cm) at intermittent intensities. ...
Article
Full-text available
Proper cycling cleat adjustment could improve triathlon performance. Recommendations have included positioning the first metatarsal head above the pedal spindle or slightly forward, but mid-foot cleat positions could be more appropriate in triathlon at constant load due to their impact on the subsequent running performance. We evaluated the impact of antero-posterior cleat position on biomechanical and physiological variables during the cycling and running parts of a simulated Sprint triathlon. Seven participants performed two 32-min cycling tests including 8 sets of 3 min 30 s intervals performed at just below the power output at the first ventilatory threshold interspersed with 30 s sprints at > 100% of the maximal aerobic power. The cycling exercises were immediately followed by a maximal running performance of 20 min. The tests were performed with a 5-mm posterior (PCP) and a 5-mm anterior (ACP) first metatarsal cleat position. The PCP decreased the energy cost of running (-5.9%; p = 0.04; effect size [ES] = 0.37) despite no significant change in cycling power output (p = 0.17; ES = 0.40) and running speed (p = 0.89; ES = 0.04). In addition, the PCP resulted in a lower recruitment of soleus during sub-maximal cycling intensity (-7.0%; p = 0.04; ES = 0.88) and of gastrocnemius medialis during the running part of the test (-25%; p = 0.04; ES = 1.05). Therefore, the PCP could be more suitable in triathlon by being more economical for subsequent running, due to a lower recruitment of calf-muscles during the sub-maximal cycling and the running part.
... Both systems usually enforce that the head of the metatarsal bones are close to the pedal axle (Ramos Ortega et al. 2012). However, no effects from changing this position to a more forward position of the foot have been observed in cycling efficiency (van Sickle Jr and Hull 2007). Differently, triathletes could benefit from moving the foot more forward in relation to the pedal, potentially reducing the load on the calf muscles and improving running after cycling (Paton and Jadine 2012). ...
Chapter
In this chapter, we intend to present information on the kinematics of cycling for recreational and professional plural. Considering that the kinematics of cycling can be affected by many aspects, we opted to discuss some of the more frequent issues that have been covered in the literature on segmental movements during cycling. We believe this chapter is an introductory reading for undergraduates and graduate students interested in understanding how kinematics can change during cycling and why it is important for training and competition. Although we mention in some sections information about technical details of motion capture systems, our purpose is not to provide a full discussion on how motion capture works. We started the chapter by introducing the importance of assessing kinematics of cyclists. We also included a brief summary with the state of the art in the use of kinematics for cycling assessment. The chapter follows with the discussion of selected topics, including the effects of body position, exercise intensity, pedaling cadence, fatigue, bike fit, and training level on the segmental movements during pedaling. Finally, we discuss some implications of segmental movements on force production and injury risk among cyclists. The chapter is finished with our conclusions and comments on future directions for research in this topic.
... For example, the long lever arm in conventional speed skates inhibited the athletes' ability to initiate ankle rotation, which resulted not only in the suppression of plantar flexion, but also in the early termination of knee and hip extension [1,2]. Furthermore, this spatial relationship between the pivot point and the ankle joint has also been studied in cycling with regard to shoe-pedal attachment locations, where moving the pivot position between the head of the first metatarsal and the posterior end of the calcaneus created a short lever arm, thereby reducing the ability of the ankle plantar flexors to generate power [6]. Another example where equipment modification affects the lever arm system can be found in sports such as in running. ...
Article
Full-text available
The purposes of the current study were to 1) test if the hinge position in the binding of skating skis has an effect on gross efficiency or cycle characteristics and 2) investigate whether hinge positioning affects synergistic components of the muscle activation in six lower leg muscles. Eleven male skiers performed three 4-min sessions at moderate intensity while cross-country ski-skating and using a klapskate binding. Three different positions were tested for the binding’s hinge, ranging from the front of the first distal phalange to the metatarsal-phalangeal joint. Gross efficiency and cycle characteristics were determined, and the electromyographic (EMG) signals of six lower limb muscles were collected. EMG signals were wavelet transformed, normalized, joined into a multi-dimensional vector, and submitted to a principle component analysis (PCA). Our results did not reveal any changes to gross efficiency or cycle characteristics when altering the hinge position. However, our EMG analysis found small but significant effects of hinge positioning on muscle coordinative patterns (P < 0.05). The changed patterns in muscle activation are in alignment with previously described mechanisms that explain the effects of hinge positioning in speed-skating klapskates. Finally, the within-subject results of the EMG analysis suggested that in addition to the between-subject effects, further forms of muscle coordination patterns appear to be employed by some, but not all participants.
... This study aimed to investigate the effects of the positional changes in well-trained cyclists. As with other similar works the need for a consistent sample of welltrained cyclists has resulted in a relatively small sample size (Grappe et al. 1998;Peveler and Green, 2011;Van Sickle and Hull, 2007). Hence, future work is required to investigate specific position related effects in a larger cohort. ...
... Los ángulos se definen como: el ángulo del tronco (α), el ángulo de articulación de la cadera (β), ángulo en el lado posterior entre la línea del muslo y una línea vertical a través de las articulaciones de la cadera determinada orientación del muslo (γ), el ángulo de articulación de la rodilla (δ), ángulo de la articulación del tobillo (ε), la orientación del pie (ζ). Otros estudios han descrito los cambios que provoca la posición del pie sobre el pedal en la cinemática y actividad de los músculos del tren inferior (Van Sickle & Hull, 2007). Estos autores describieron como la ubicación antero-posterior de la cala modifica los ángulos de pedaleo y por lo tanto la elongación de la musculatura afectada, aunque en este caso no se encontró una influencia significativa sobre el VO2, aunque si hay diferencias marginales entre la posición adelantada y la retrasada del pie sobre el pedal y esta variable fisiológica. ...
Article
Introducción: El estudio de las presiones plantares en ciclistas está es- casamente analizado y en la mayoría de los estudios se ha realizado con ciclistas no profesionales. El objeto del presente estudio fue determinar el efecto que produce el aumento de la potencia de pedaleo sobre las presiones plantares en ambos pies en ciclistas profesionales. Material y métodos: Con el sistema Biofoot/IBV®, se registraron las presiones plantares a 50 ciclistas profesionales. El pie se dividió en 9 zonas: 3 zonas para los dedos (D1, D2, D3), 3 zonas para los metatarsos (C1, C2, C3), 2 zonas para el mediopié (M1, M2) y una zona para el re- tropié (T). Se fijó la cadencia en 100 rpm y se contrabalanceó el orden de aplicación de las pruebas con las potencias de 100 W y 200 W entre los ciclistas participantes. Se realizó un ANOVA de medidas repetidas con 3 factores intra-sujetos: Potencia (100 w vs. 200 w) x Pie (derecho vs. izquierdo) x Zonas (D1, D2, D3, C1, C2, C3, M1, M2 y T ). Resultados: Se encontró una interacción significativa Potencia x Zona, F(2,51,102,76) = 34,82, p < 0,001, η2 = 0,46. Los análisis post hoc indicaron que, aunque el efecto de potencia (mayores presiones en la potencia 200 w respecto a la de 100 w) fue significativo en todas las zonas (ps < 0,031), dicho aumento de potencia afectó de manera desigual a la pre- sión que recibieron las diferentes zonas. No se encontraron diferencias en la presión debidas al Pie (p = 0,933).Conclusiones: Las presiones se reparten de manera desigual en el pie, soportando mayor carga las zonas del primer dedo y primer metatarso. Las zonas que mayor aumento de presión reciben por efecto del incre- mento de la potencia, son las zonas mediales, destacando especialmente la zona del primer metatarso. Deberán considerarse estos resultados para la confección de plantillas de acomodación selectiva.
Article
Full-text available
Relying on a biomechanical model of the lower limb which treats the leg-bicycle system as a five-bar linkage constrained to plane motion, a cost function derived from the joint moments developed during cycling is computed. At constant average power of 200 W, the effect of five variables on the cost function is studied. The five variables are pedalling rate, crank arm length, seat tube angle, seat height, and longitudinal foot position on the pedal. A sensitivity analysis of each of the five variables shows that pedalling rate is the most sensitive, followed by the crank arm length, seat tube angle, seat height, and longitudinal foot position on the pedal (the least sensitive). Based on Powell's method, a multivariable optimization search is made for the combination of variable values which minimize the cost function. For a rider of average anthropometry (height 1.78 m, weight 72.5 kg), a pedalling rate of 115 rev min-1, crank arm length of 0.140 m, seat tube angle of 76 degrees, seat height plus crank arm length equal to 97% of trochanteric leg length, and longitudinal foot position on the pedal equal to 54% of foot length correspond to the cost function global minimum. The effect of anthropometric parameter variations is also examined and these variations influence the results significantly. The optimal crank arm length, seat height, and longitudinal foot position on the pedal increase as the size of rider increases whereas the optimal cadence and seat tube angle decrease as the rider's size increases. The dependence of optimization results on anthropometric parameters emphasizes the importance of tailoring bicycle equipment to the anthropometry of the individual.
Article
Current understanding of how muscles coordinate walking in humans is derived from analyses of body motion, ground reaction force and EMG measurements. This is Part I of a two-part review that emphasizes how muscle-driven dynamics-based simulations assist in the understanding of individual muscle function in walking, especially the causal relationships between muscle force generation and walking kinematics and kinetics. Part I reviews the strengths and limitations of Newton–Euler inverse dynamics and dynamical simulations, including the ability of each to find the contributions of individual muscles to the acceleration/deceleration of the body segments. We caution against using the concept of biarticular muscles transferring power from one joint to another to infer muscle coordination principles because energy flow among segments, even the adjacent segments associated with the joints, cannot be inferred from computation of joint powers and segmental angular velocities alone. Rather, we encourage the use of dynamical simulations to perform muscle-induced segmental acceleration and power analyses. Such analyses have shown that the exchange of segmental energy caused by the forces or accelerations induced by a muscle can be fundamentally invariant to whether the muscle is shortening, lengthening, or neither. How simulation analyses lead to understanding the coordination of seated pedaling, rather than walking, is discussed in this first part because the dynamics of pedaling are much simpler, allowing important concepts to be revealed. We elucidate how energy produced by muscles is delivered to the crank through the synergistic action of other non-energy producing muscles; specifically, that a major function performed by a muscle arises from the instantaneous segmental accelerations and redistribution of segmental energy throughout the body caused by its force generation. Part II reviews how dynamical simulations provide insight into muscle coordination of walking.
Article
VO2 was obtained for 10 women bicycling on rollers at 3 saddle heights (SH), 95, 100 and 105% trochanteric height. Kinematic patterns described by the hip, knee, ankle and foot were discerned from one pedal cycle at each of the 3 SH. Subjects cycled on a Fuji Dynamic 10 10-speed bicycle, at 60 rpm, (a work load of 799 kpm/min was applied by a tensioning belt from a bicycle ergometer) until they reached steady state. Expired air was then collected and cine films were taken during gas collection. The 100% SH was most efficient, mean values for 95, 100 and 105% SH were 1.69, 1.61 and 1.74 lit/min, respectively. Kinematic patterns showed no variation in the range of motion (ROM) at the hip, values at the dead centers (DC) did change. The ROM at the knee varied from 69 to 82.9 degrees, 95 to 105% SH, values at the DC varied also. Plantar flexion (PF) at bottom dead center increased by 10% from 95 to 105% SH. Foot angle showed no significant variation with increasing SH. The major adaptations to increases in SH are found at the knee and in ankle PF.
Article
The effect of saddle height upon oxygen consumption during bicycle ergometer work was measured. Five subjects were tested on a continuous work protocol from 50 watts to 200 watts in 25 watt increments at experimental saddle heights of 100%, 103%, 106%, 109%, and 112% of inside leg length measured from the ischium to the floor. Data were recorded on Vo2, Vco2, VE, and heart rate. It was found that Vo2 progressively increased as saddle height increased; the highest Vo2 occurred at the highest experimental setting of 112%; the most effective saddle positions in the experiment as measured by lowest Vo2 per unit of work were 100% and 103%; and there was no significant difference between the VO2 AT 100% AND 103%. It was concluded that in light of our data and earlier data showing power output to be maximized at 104% (by our measurement method), the saddle height of choice should be approximately 103% to 104% of leg length. A convenient and objective method for setting seat height is presented.
Article
This study evaluated the effect of time of day on performance of high-intensity, constant-power cycle ergometry by both men and women. Subjects performed all-out cycle ergometer tests in the morning and in the afternoon in randomized order. For all tests, work rate was a constant 5.0 W.kg-1 (women, n = 6) or 6.0 W.kg-1 (men, n = 8). Total work performed was 9.6% greater in the afternoon (mean +/- SE, 348.8 +/- 40.6 J.kg-1) compared to the morning (318.2 +/- 39.5 J.kg-1). The greater amount of work in the afternoon was associated with a 5.1% higher aerobic power and a 5.6% larger anaerobic contribution. There was no interaction between gender and the effect of time of day on the aerobic or anaerobic contributions. These results provide evidence of a circadian rhythm in aerobic and anaerobic responses to high-intensity short-duration exercise, in women as well as in men.
Article
In this study we evaluated the physiological and biomechanical responses of 'elite-national class' (i.e., group 1; N = 9) and 'good-state class' (i.e., group 2; N = 6) cyclists while they simulated a 40 km time-trial in the laboratory by cycling on an ergometer for 1 h at their highest power output. Actual road racing 40 km time-trial performance was highly correlated with average absolute power during the 1 h laboratory performance test (r = -0.88; P < 0.001). In turn, 1 h power output was related to each cyclists' V̇O2 at the blood lactate threshold (r = 0.93; P < 0.001). Group 1 was not different from group 2 regarding V̇O(2max) (approximately 70 ml·kg-1·min-1 and 5.01 l·min-1) or lean body weight. However, group 1 bicycled 40 km on the road 10% faster than group 2 (P < 0.05; 54 vs 60 min). Additionally, group 1 was able to generate 11% more power during the 1 h performance test than group 2 (P < 0.05), and they averaged 90 ± 1% V̇O(2max) compared with 86 ± 2% V̇O(2max) in group 2 (P = 0.06). The higher performance power output of group 1 was produced primarily by generating higher peak torques about the center of the crank by applying larger vertical forces to the crank arm during the cycling downstroke. Compared with group 2, group 1 also produced higher peak torques and vertical forces during the downstroke even when cycling at the same absolute work rate as group 2. Factors possibly contributing to the ability of group 1 to produce higher 'downstroke power' are a greater percentage of Type I muscle fibers (P < 0.05) and a 23% greater (P < 0.05) muscle capillary density compared with group 2. We have also observed a strong relationship between years of endurance training and percent Type I muscle fibers (r = 0.75; P < 0.001). It appears that 'elite-national class' cyclists have the ability to generate higher 'downstroke power', possibly as a result of muscular adaptations stimulated by more years of endurance training.
Article
The aim of the study was to quantify the activity as recorded by electromyography during ergometer cycling in eleven different muscles of the lower extremity. Eleven healthy subjects rode in twelve different ways at different work-load, pedalling rate, saddle height and pedal foot position. Vastus medialis and lateralis, gastrocnemius medialis and lateralis and the soleus muscle were the most activated muscles. Changes in muscle activity during different calibrations were studied in eight of the eleven muscles. An increase in work-load significantly increased the mean maximum activity in all the eight muscles investigated. An increase of the pedalling rate increased the activity in the gluteus maximus, gluteus medius, vastus medialis, medial hamstring, gastrocnemius medialis and soleus muscles. An increase of the saddle height increased the muscle activity in the gluteus medius, medial hamstring and gastrocnemius medialis muscles. Use of a posterior pedal foot position increased the activity in the gluteus medius and rectus femoris muscles, and decreased the activity in the soleus muscle.
Article
The ankle joint moment, joint compressive force, and Achilles tendon force obtained during ergometer cycling were calculated by using a quartz force-measuring transducer mounted on the pedal. Six healthy subjects rode in 11 different ways at different workloads, pedalling rates, saddle heights, and pedal foot positions. The mean maximum dorsiflexing load moment about the ankle joint during standardized ergometer cycling was calculated to 30.9 nm. The mean ankle joint compressive force and mean Achilles tendon force measured 1008 N (1.4 times body weight) and 762 N (1.1 times body weight), respectively. The ankle joint moment was significantly changed by a change of workload or pedal foot position.
Article
This study 1) quantitates the effect of a 42.2-km footrace (marathon) on leg extensor strength (maximal peak torque, MPT) and work capacity (WC, measured during a leg extensor fatigue test), and 2) describes the effect of either a rest or exercise regimen for 1 wk after the marathon on the recovery of MPT and WC. Ten trained male runners performed personal records in a marathon and were then randomly assigned to either a rest or exercise-recovery group. The rest group did not train, whereas the exercise group ran 20-45 min/day at their selected intensity of exercise [50-60% maximal O2 consumption (Vo2max)] during the recovery week. MPT was measured at 1.1, 3.2, and 5.3 rad X s-1. The total work generated during a 50-contraction active extension-passive flexion fatigue test conducted at 3.2 rad X s-1 was defined as WC. Reports of perceived soreness of the quadriceps were obtained before each strength-testing session. These measurements were obtained before the marathon and 15-20 min and 1, 3, 5, and 7 days postmarathon. A significant reduction in MPT and WC resulted and continued 1 day postmarathon. MPT of both groups improved through day 5 postmarathon at 1.1 and 3.2 rad X s-1. MPT of the rest group improved through day 7 postmarathon but remained less than premarathon MPT. Recovery of MPT was impaired in the exercise group through days 5-7 postmarathon after 40-45 min exercise at 60% Vo2max. WC was recovered 3 days postmarathon in the rest group but was still impaired 7 days postmarathon in the exercise group.(ABSTRACT TRUNCATED AT 250 WORDS)
Article
This model is used to understand the interrelationships of the physiological factors determining endurance performance ability during prolonged exercise. Early studies found that marathon runners maintain a velocity in competition that corresponds to the intensity at which lactate begins to accumulate in blood and muscle [7, 8, 19]. From this observation, the concept developed that this blood lactate threshold (LT Vo2) reflects the degree of muscular stress, glycogenolysis and fatigue. However, it was not clear whether the lactate accumulation was a result of cardiovascular limitations linked to oxygen delivery, as reflected by Vo2max [54], as opposed to metabolic factors in the exercising muscle related to the extent to which mitochondrial respiration is disturbed to maintain a given rate of O2 consumption [29, 30]. Two studies were performed to determine whether LT Vo2 was tightly coupled to Vo2max. In one study, endurance-trained ischemic heart disease patients were observed to possess a Vo2max that was 18% below that of normal master athletes who followed the patient's training program and who displayed the same performance ability as the patients. Both the patients and the normal men displayed an identical LT Vo2 (i.e., 37 ml/kg/min) (Fig. 2.5). Therefore, performance was determined primarily by LT Vo2 instead of Vo2max in this situation, albeit with abnormal subjects. In a second study we assembled two groups of competitive cyclists who were identical in Vo2max but differed by having a high or low LT Vo2 (82% vs. 66% Vo2max) [13]. When cycling at 80-88% Vo2max, the low LT group displayed more than a 2-fold higher rate of muscle glycogen use and blood lactate concentration, and as a result were able to exercise only one-half as long as the high LT group. Performance time for a given Vo2 was clearly related to LT Vo2 instead of Vo2max (Fig. 2.6). This is not to say that Vo2max plays no role in determining LT Vo2, because as in heart disease patients, it clearly sets the upper limit. Indeed, we have seen that much of the variance (i.e., 31-72%) in LT Vo2 is related to Vo2max. (Fig. 2.11.) However, improvements in performance after the first 2-3 yr of intense training are associated with improvements in LT Vo2, whereas Vo2max generally increases very little thereafter (Table 2.3). The next question concerns the factors responsible for further increases in LT Vo2 and Performance. Another major factor determining LT Vo2 is the muscle's Aerobic Enzyme Activity or mitochondrial respiratory capacity, as discussed in previous reviews [29, 30].(ABSTRACT TRUNCATED AT 400 WORDS)