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“Cycling Attributes that Enhance Running Performance after the Cycle Section in Triathlon” by Etxebarria N, et al.
International Journal of Sports Physiology and Performance
© 2013 Human Kinetics, Inc.
Note. This article will be published in a forthcoming issue of the
International Journal of Sports Physiology and Performance. The article
appears here in its accepted, peer-reviewed form, as it was provided by
the submitting author. It has not been copyedited, proofread, or
formatted by the publisher.
Section: Original Investigation
Article Title: Cycling Attributes that Enhance Running Performance after the Cycle Section in
Triathlon
Authors: Naroa Etxebarria
1,2
, Judith M. Anson
2
, David B. Pyne
2,3
, and Richard A. Ferguson
1
Affiliations:
1
School of Sport, Exercise and Health Sciences, Loughborough University,
Loughborough, UK.
2
National Institute of Sports Studies (NISS), Faculty of Health, University
of Canberra, ACT, 2601, Australia.
3
Physiology, Australian Institute of Sport, ACT, 2617,
Australia.
Journal: International Journal of Sports Physiology and Performance
Acceptance Date: January 10, 2013
©2013 Human Kinetics, Inc.
“Cycling Attributes that Enhance Running Performance after the Cycle Section in Triathlon” by Etxebarria N, et al.
International Journal of Sports Physiology and Performance
© 2013 Human Kinetics, Inc.
Title
CYCLING ATTRIBUTES THAT ENHANCE RUNNING PERFORMANCE AFTER THE
CYCLE SECTION IN TRIATHLON
Authors: Naroa Etxebarria
1,2
, Judith M Anson
2
, David B Pyne
2,3
and Richard A Ferguson
1
Institutions
1
School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough,
LE11 3TU, UK.
2
National Institute of Sports Studies (NISS), Faculty of Health, University of Canberra, ACT,
2601, Australia.
3
Physiology, Australian Institute of Sport, ACT, 2617, Australia.
Corresponding author (and present address)
Naroa Etxebarria
National Institute of Sports Studies (NISS)
Faculty of Health
University of Canberra
ACT, 2601, Australia
Email: naroa.etxebarria@canberra.edu.au
Telephone: +61 26201 6325
Fax: +61 26201 5615
Word count: 3495 ; Abstract word count: 250; No. of Tables and Figures: 5.
“Cycling Attributes that Enhance Running Performance after the Cycle Section in Triathlon” by Etxebarria N, et al.
International Journal of Sports Physiology and Performance
© 2013 Human Kinetics, Inc.
ABSTRACT
Purpose: To determine how cycling with a variable (triathlon-specific) power distribution
affects subsequent running performance, and quantify relationships between an individual
cycling power profile and running ability after cycling. Methods: Twelve well-trained male
triathletes (
peak
4.9 ± 0.5 L.min
-1
; mass 73.5 ± 7.7 kg, mean ± SD) undertook a cycle
peak
and maximal aerobic power test, and a power profile involving six maximal efforts (6 s - 10
min). Each subject then performed two experimental 1 h cycle-run trials at either triathlon-
specific variable (VAR) power ranging from 40-140% MAP or constant (CON) power (both at
65% MAP) followed by an outdoors 9.3 km time trial run. Subjects also completed a control 9.3
km run with no preceding exercise. Results: The 9.3 km run time was 42; ±37 s slower (mean;
±90% confidence limits, CL) after VAR (35:32 ± 3:18 min:s, mean ± SD) compared with CON
power cycling (34:50 ± 2:49 min:s). This decrement (35; ±20 s, mean; ± 90% CL) was primarily
evident in the first half of the run. Higher blood lactate and rating of perceived exertion after 1 h
VAR cycling were moderately correlated (r=0.51-0.55; ~±0.40) with a larger decrement in run
performance. There were no clear associations between the power profile test and decrement in
run time after VAR compared with CON. Conclusions: A highly variable power distribution in
cycling is likely to impair 10 km triathlon run performance. Training to lower physiological and
perceptual responses during cycling should limit the negative effects on triathlon running.
Key words: cycle-run, power-profile, constant power
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“Cycling Attributes that Enhance Running Performance after the Cycle Section in Triathlon” by Etxebarria N, et al.
International Journal of Sports Physiology and Performance
© 2013 Human Kinetics, Inc.
INTRODUCTION
In triathlon, the physical demands of each race depend on the host venue and race
dynamics (positioning and tactics). Training specificity and development of effective tactical
strategies for competition are perennial challenges for coaches and triathletes. The cycle section
(prior to the run and after the swim section) of an Olympic distance triathlon race at the elite
level is ~1 h long and well-developed fitness and technical skills are especially important on
criterium-type courses. Cycling is typically performed at a mean intensity of ~60-65% of an
individual’s maximal aerobic power (MAP) with a highly variable power distribution including
efforts of >130% MAP and sustained efforts at ~80-90% MAP.
1
As cycle courses become more
technical, individual and team tactics continue to evolve. The power variations encountered in
the cycling section are larger and more frequent (Etxebarria N, Loughborough University,
unpublished data), presumably increasing the degree of physiological strain even for the stronger
cyclists.
2,3
The third and final run section (influenced by fatigue accumulated during the
preceding cycling), is often decisive in determining the overall outcome of races particularly for
male competitors.
4
Therefore, determining the consequences of race-specific cycling on
subsequent 10 km running performance is important in order to characterize sport-specific race
demands. This information would be useful to optimize sport-specific training as well as physical
and tactical capacities for enhancing triathlon performance.
The highly variable power distribution during the triathlon cycle section is likely to
amplify differences in physiological response
2,3,5
and performance outcomes associated with
constant vs variable power cycling. Several experimental studies investigating the effects of
variable power have employed relatively narrow power variations fluctuations using repetitive
intervals of duration and intensity.
2,6,7
Some studies report that variable intensity cycling (for
“Cycling Attributes that Enhance Running Performance after the Cycle Section in Triathlon” by Etxebarria N, et al.
International Journal of Sports Physiology and Performance
© 2013 Human Kinetics, Inc.
durations between 30-60 min) favors subsequent running
8,9
while others report the opposite.
8
These conflicting findings need to be resolved to clarify ambiguity on the effect of variable
power cycling on subsequent exercise by using sport-specific power variations and performance
measures.
Drafting, variability in technicality of courses, and race tactics in Olympic distance
triathlon, make it difficult to assess laboratory-based physiological and performance
measurements that relate directly with race outcomes. Critical power, a traditional performance
measure derived via ergometry testing, identifies the highest power that can be sustained for an
extended time (typically 30-60 min) without fatigue
10
, and correlates highly with performance in
some endurance events such as cycling time trials.
11
Given the inherent variability in power
output within and between triathlon races, the athlete with the highest sustainable power output
for 1 h, is not necessarily the most successful. A laboratory-based cycle test that assesses a
triathlete’s ability to perform over a wide range of physiological domains is more relevant for
performance evaluation and prediction. The ‘power profile’ test has been used successfully in
road cycling
12
and it is somewhat surprising that the performance capabilities of triathletes have
not been similarly characterized.
The main aim of this study was to compare the effects of 1 h cycling at 65% MAP
incorporating a triathlon-specific power distribution with 1 h constant power cycling on
subsequent running performance. A secondary aim was to study the relationships between
maximal power produced during intermittent maximal cycling sprints of different durations and
running performance after variable power cycling.
“Cycling Attributes that Enhance Running Performance after the Cycle Section in Triathlon” by Etxebarria N, et al.
International Journal of Sports Physiology and Performance
© 2013 Human Kinetics, Inc.
METHODS
Experimental design
A controlled laboratory-based investigation was conducted to study how 1 h variable
(VAR) and constant (CON) power cycling affects subsequent 9.3 km running performance
compared to running with no preceding exercise. We also correlated running performance after
CON and VAR with the ability to generate maximal power during short and longer efforts
through a cycling power profile test.
Subjects
Twelve well-trained male triathletes participated in this study. Their physical
characteristics were: age 28 ± 5 y, height 1.80 ± 0.06 m, body mass 73.4 ± 7.8 kg,
peak
4.9 ±
0.5 L.min
-1
; mean ± SD). The typical weekly training volume for the group was 4 h of
swimming, 8 h of cycling and 3 h of running, with one higher intensity running interval and one
cycling interval session a week. Subjects were instructed to abstain from any physical exercise,
caffeine or alcohol and replicate the same dietary practice in the 24 h prior to each trial. The
study was approved by the Loughborough University Ethics Advisory Committee and the
Committee for Ethics in Human Research at the University of Canberra. All subjects provided
written informed consent after a verbal explanation of the study protocol and experimental
procedures was provided to them.
Preliminary testing
Maximal Aerobic Power and
peak
test
Following a 10 min warm up at 125 Watts (W) subjects performed a progressive
incremental maximal test on an electromagnetically braked cycle ergometer (Excalibur Sport,
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2
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2
“Cycling Attributes that Enhance Running Performance after the Cycle Section in Triathlon” by Etxebarria N, et al.
International Journal of Sports Physiology and Performance
© 2013 Human Kinetics, Inc.
Netherlands) to establish their
peak
and MAP. The starting power output was 150 W and
increments of 5 W every 15 s were employed to ensure exhaustion was reached after 10 min.
Pedal cadence was freely chosen by each participant and kept constant during the test. The MAP
was defined as the average of the four highest consecutive power outputs during the test. Expired
ventilation was measured continuously throughout the test.
Power profile
The power profile test protocol, based on that described by Quod et al.,
10
consisted of six
maximal efforts (6, 15, 30 s and 1, 4 and 10 min) with an active recovery period (75-125 W)
between each effort (174, 225, 330, 480 and 600 s, respectively). Following a 10 min warm up
(125 W), the power profile test was completed on a custom-built wind-braked cycle ergometer
(Australian Institute of Sport (AIS), Canberra, Australia) fitted with the triathletes’ own pedals
and adjusted to their usual bike position. Power was recorded at a frequency of 0.5 Hz. Each
athlete self-selected cadence and was able to change gears during the efforts as required. Data
were analyzed using SRM software (v6.40.05, Schoberer Rad Messtechnik, Germany). The
maximal efforts during the power profile test were subsequently compared to maximal efforts of
the same duration encountered during 12 race power profiles by five different athletes (over
seven different triathlon courses) during the international season of Olympic distance triathlon
during 2011 (unpublished data).
Experimental trials
The experimental trials were performed at least 5 days after the preliminary testing. Each
triathlete performed three different experimental trials: two 1 h cycle trials at a 65% MAP mean
power output at either constant power (CON) or variable power (VAR), both followed by a 9.3
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“Cycling Attributes that Enhance Running Performance after the Cycle Section in Triathlon” by Etxebarria N, et al.
International Journal of Sports Physiology and Performance
© 2013 Human Kinetics, Inc.
km run time trial. A third experimental trial consisted of a run time trial where no preceding
cycling was performed (NO-EX). The power distribution throughout VAR was characterized by
variable intensities often encountered during races (40-140% MAP) and efforts of different
duration (in order 10, 40, 90, 30 and 20 s) – a representative section of a VAR trial is shown in
Figure 1. All three trials were conducted in a counterbalanced and randomized order, at least 7
days apart. The cycling was performed in the laboratory using an electromagnetically braked
cycle ergometer. For the CON and VAR trials, subjects performed a 10 min warm up at 125 W
on the cycle ergometer while the warm-up for the NO-EX run was a 20 min low-intensity run.
Subjects self-selected their preferred cadence during the first trial and were asked to replicate this
cadence for the second trial to avoid any confounding effects on physiological or neuromuscular
responses. Athletes were allowed to drink water ad libitum but no sports drinks or other types of
ergogenic aids were permitted. Immediately after both CON and VAR cycle trials subjects
changed into their running shoes (taking 90 s) and started their 9.3 km time trial run. The start
and finish line was positioned outside the exit door of our ground floor laboratory where the
cycle ergometry was conducted. The run involved a 4-lap outdoor road course and split times for
each lap were recorded. At the end of the run subjects were asked to rate their effort on a scale
between 0-100%: 0% representing no effort at all, and 100% giving absolutely everything.
Subjects also used a Visual Analog scale of 1 – 5 indicating how they felt physically with 1
representing “terrible” and 5 “fantastic“ (AIS, Effort-Sensation Scale, Version 2.10, January
2010).
Anthropometric and physiological measurements
Height, body mass and sum of seven skinfolds (triceps, subscapular, biceps, supraspinale,
abdominal, front thigh and medial calf) were measured on the first visit to the laboratory.
“Cycling Attributes that Enhance Running Performance after the Cycle Section in Triathlon” by Etxebarria N, et al.
International Journal of Sports Physiology and Performance
© 2013 Human Kinetics, Inc.
Pulmonary gas exchange was measured and analyzed by a custom-built open circuit indirect
calorimetry system described previously.
13
The sampling rate was set to 30 s and the mean of the
two highest consecutive readings used to determine an individual’s
peak
during the maximal
progressive test. Heart rate was recorded using a Polar heart rate monitoring system (Polar Heart
Rate Monitor, Kempele, Finland) throughout the maximal test, at the end of each effort of the
power profile, and at 20, 40 and 60 min of VAR and CON cycling. A 5 L capillary blood
sample was drawn from a fingertip at the termination of the maximal cycling test, after the 1, 4
and 10 min efforts during the power profile, and after 60 min of both cycling trials to measure
blood lactate concentration (Lactate Pro, Arkray, Kyoto, Japan). Hydration status was
determined using a digital urine refractometer (UG- - Atago, Japan) before each experimental
trial. Rating of perceived exertion (RPE) with a scale of 0 (no exertion) to 10 (maximal exertion)
was recorded at 20, 40 and 60 min during the cycling trials and at the end of each 9.3 run trial.
Statistical Analysis
Descriptive data are shown as mean ± SD. An analytical approach determining
practical/clinical significance of effects using magnitude-based inferences and precision of
estimation was employed.
14
Mean effects of the CON and VAR power profiles on running
performance were estimated via the unequal-variances t statistic. Precision of estimation was
indicated with 90% confidence limits (CL). The difference between the two groups at any given
point in time was expressed as a percentage of baseline score via analysis of log-transformed
values, in order to reduce bias arising from non-uniformity of error. Standardized difference
scores or the effect size (ES) between the groups were interpreted according to the following
criteria: < 0.2 trivial, 0.2-0.6 small, 0.6-1.2 moderate, 1.2-2.0 large and > 2.0 very large.
15
A
standardized effect was inferred to be unclear when its confidence interval spanned both
VO
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“Cycling Attributes that Enhance Running Performance after the Cycle Section in Triathlon” by Etxebarria N, et al.
International Journal of Sports Physiology and Performance
© 2013 Human Kinetics, Inc.
substantially positive (+0.2) and substantially negative (-0.2) values. Pearson’s correlation
analysis was used to measure the degree of association between different physiological and
performance markers using a scale of magnitudes:
16
< 0.1 trivial, 0.1-0.3 small, 0.3-0.5
moderate, 0.5-0.7 large, and extended
14
to include 0.7-0.9 v. large, > 0.9 nearly perfect. A
correlation was deemed unclear if the confidence interval spanned both -0.1 and +0.1 values. To
compare the magnitude of variation in pacing of the 9.3 km run for the three experimental
groups, we computed a ratio of the % coefficients of variation (%CV) in quartile split times.
Ratios within a range of 0.9 – 1.1 were considered trivial (see justification at
http://yahoogroups.com/groups/sportscience/message/2538). Ratios <0.9 indicate the pacing of
split times was substantially less variable for the first measure of the comparison. Statistical
significance was set at p < 0.05.
RESULTS
Cycling MAP was 411 ± 39 W (mean ± SD),
peak
4.9 ± 0.5
L.min
-1
and sum of
skinfolds 56 ± 15 mm at baseline. All trials were performed with subjects in an euhydrated status
(urine specific gravity <1.020). The 1 h cycle trials at CON and VAR were performed at 65%
MAP equivalent to a mean power output of 267 ± 25 W for both trials.
Time trial run performance
Both runs with preceding cycling were substantially slower (Table 1) compared to the run
with no cycling (33:42 ± 2:32 min:s). The overall 9.3 km run time was 42 ± 37 s (mean; ± 90%
CL) slower after VAR (35:32 ± 3:18 min:s, mean ± SD) compared with CON (34:50 ± 2:49
min:s). The decrement after VAR appeared primarily in the first half of the run (35 ± 20 s, mean;
± 90% CL slower than CON). The variation in pacing of the four-lap run was substantially
VO
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“Cycling Attributes that Enhance Running Performance after the Cycle Section in Triathlon” by Etxebarria N, et al.
International Journal of Sports Physiology and Performance
© 2013 Human Kinetics, Inc.
greater after VAR compared with CON (ratio of coefficient of variation = 0.79). The NO-EX run
had the most evenly paced strategy followed by the post-CON run (Figure 2).
The control run (NO-EX) elicited the highest B
La
response out of the three running time trials
(7.5 ± 2.4 mmol.L
-1
) with a trivial difference between trials (CON 5.9 ± 2.5 and VAR
6.7 ± 2.3 mmol.L
-1
, Table 1). Subjects reported they gave 94 ± 5% effort during the run after
CON, 95 ± 6% during the run after VAR and 93 ± 9% after NO-EX. There were trivial
differences between the cycle strategies on how subjects felt during the run (3.1 ± 1 for CON and
3.1 ± 1 for VAR; scale 1-5) with an unclear difference between the two cycle strategies and NO-
EX (3.4 ± 0.8).
One hour constant and variable power cycling
There was a very large difference in B
La
at the end of the 1 h cycle (Table 1) with a
higher concentration after VAR (8.2 ± 3.6 mmol.L
-1
) than CON (3.3 ± 1.5 mmol.L
-1
). The RPE
for CON and VAR was similar at 20 min (6.0 ± 1.6 vs 5.9 ± 1.3 respectively) but substantially
higher for VAR at 40 min (6.9 1.4 vs 6.3 ± 1.6 units) and 60 min (7.8 ± 1.1 vs 6.3 ± 1.6 units)
of the 1 h cycle. HR followed a similar pattern as RPE with a trivial difference between the
cycling trials at 20 min (155 ± 13 vs 155 ± 16 for CON and VAR) but substantially higher at 40
min (162 ± 15 vs 156 ± 13 b.min
-1
) and 60 min (161 ± 16 vs 155 ± 13 b.min
-1
) in VAR. A better
run time was associated with a lower B
La
and RPE at the end of the 1 h cycling trials (Figure 3).
Power profile test
The RPE,
and B
La
during the power profile test are shown in Table 2. The athletes
performed their 4 min and 10 min efforts at 90 and 88% of their
peak
. The curvilinear
relationship between power output and time generated by the cycling power profile in our
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2
“Cycling Attributes that Enhance Running Performance after the Cycle Section in Triathlon” by Etxebarria N, et al.
International Journal of Sports Physiology and Performance
© 2013 Human Kinetics, Inc.
triathletes was similar to that previously documented in road cyclists, although the power outputs
were lower (offset) in comparison. This profile of the triathletes also compared well with the
equivalent (time) maximal efforts encountered during the 12 cycle race-profiles of elite-level
triathlon races (Figure 4,). However, our triathletes achieved higher power output in the short
efforts but were not able to sustain as high a power output for the longer efforts as elite athletes
did in racing.
One subject’s power profile results were excluded due to early fatigue and subsequent
inability to generate maximal power. The only clear predictor of impaired running performance
after VAR cycling was the B
La
response during the 10 min effort of the power profile. Subjects
with a higher B
La
response had a bigger impairment of running after VAR (r=0.50; -0.04 to 0.81,
90% confidence interval). Body mass was positively correlated with absolute mean power output
during the 15 s (r=0.82, 0.52 to 0.94) and 30 s (r=0.83, -0.66 to 0.35) efforts. Absolute peak
power output during the 6 and 15 s efforts was inversely correlated with running ability after
both 1 h cycling trials (r=0.50 – 0.67; ~±0.40). However, were unable to identify clear
relationships between peak and mean power output during the power profile test and difference
in run time between CON and VAR: peak power during 6 s (r=-0.29, -0.71 to 0.27) and 15 s
sprint (r=-0.22, -0.66 to 0.35), and mean power during 1 min (r=-0.32, -0.71 to 0.21), 4 min
(r=0.14, -0.41 to 0.62) and 10 min (r=0.16, -0.40 to 0.63) efforts.
DISCUSSION
The VAR cycle protocol implemented in this study during a 1 h cycle characterized by a
triathlon-specific power distribution substantially slowed the subsequent 9.3 km run time. Nearly
85 % of the time lost occurred during the first half of the run. The slower run time after VAR
observed in the current study is in agreement with previous results over a 30 min cycle and 5 km
“Cycling Attributes that Enhance Running Performance after the Cycle Section in Triathlon” by Etxebarria N, et al.
International Journal of Sports Physiology and Performance
© 2013 Human Kinetics, Inc.
run.
8
The elevated physiological responses during VAR cycling were most prominent towards
the end of the cycle just before the start of the run, which likely explains the slow start in the
subsequent run section. Higher physiological and perceptual responses during variable power
cycling were substantially correlated with impaired running performance compared to constant
power cycling. Power output during the power profile test alone does not explain greater
impairment in run performance after variable power cycling.
The probable reason for the first running split being slowest following VAR is due to the
elevated physiological (HR and B
La
) state at the end of VAR cycling. The higher B
La
concentration towards the end of VAR is accompanied by higher metabolic acidosis when
buffering capacity is limited.
17
This scenario could explain the higher associated RPE readings,
18
compromising the start of the running performance after VAR. Such elevations in HR and B
La
during variable power cycling have not always been identified by studies implementing narrow
power variations.
5,6,19
The divergent findings between previous studies and our study reiterates
the importance of implementing race-specific power fluctuations to better understand the
physiological demands of the cycle section in triathlon, and their impact on performance.
The present study involved a self-paced 9.3 km run time trial performance, which is
slightly different from a pack run scenario often seen at the start of the run of a triathlon race.
Our data indicate that 1 h of variable power cycling leads to uneven pacing on subsequent
running over a 4 lap run course. The athletes in this study were not worried about ‘race position’
yet the first half of the run was substantially slower after VAR than CON. The longer the
sporting event (~ >10 min) the more beneficial it is to keep an even pace during racing.
20-22
Despite this fact, the first split of a usual 4 lap run course in triathlon however, is often the fastest
by as much as 1 km.h
-1
compared to the mean run speed for the rest of the run.
23
In a race
“Cycling Attributes that Enhance Running Performance after the Cycle Section in Triathlon” by Etxebarria N, et al.
International Journal of Sports Physiology and Performance
© 2013 Human Kinetics, Inc.
situation where tactics often dictate pacing, adopting a much faster first quarter of the run after a
taxing variable cycle section is likely to increase the risk of fatigue towards the finish line.
Assessing the power profile in our well-trained triathletes has allowed us to explore some of the
key physiological determinants of performance in triathlon. A low B
La
concentration following
the 10 min sustained bout, correlated moderately with enhanced performance after VAR cycling.
Lower B
La
after a sustained maximal effort suggests enhanced lactate uptake within the muscle
associated with a higher aerobic capacity.
24
The positive relationship between a low B
La
during
the maximal 10 min effort with a favorable running performance after VAR reinforces the
benefits of a higher aerobic capacity to recover between high intensity bouts.
25
The power
outputs of our well-trained subjects were consistently 10% lower than the road cyclists
12
across
the efforts. We acknowledge the fact that athletes undertake a higher number of efforts during
racing, however, our laboratory results in triathletes are in agreement with those laboratory
results seen in cyclists with a nearly perfect correlation (r = 1.00, 0.97 – 1.00) with the efforts
displayed in the field. The higher absolute power output during the short cycling efforts was
positively associated with a higher body mass and negatively correlated with run performance
after 1 h cycling. Triathletes need to develop the capacity to generate adequate power in cycling
by increasing relative power output (W/Kg) without compromising the subsequent running
performance.
Practical implications
In addition to impaired overall performance, a slower first half of the run section after
VAR cycling could impair the ability to establish and/or sustain a favorable race position.
Triathletes should avoid varying their pace too much during the run aiming for a solid start to
avoid a decay in speed in the latter stages. Triathletes with superior technical and physical
“Cycling Attributes that Enhance Running Performance after the Cycle Section in Triathlon” by Etxebarria N, et al.
International Journal of Sports Physiology and Performance
© 2013 Human Kinetics, Inc.
cycling ability can save energy during the cycle section for the run by riding more
conservatively, which might compromise race performance or depending on tactical
considerations, push to the lead making weaker cyclists tired for the subsequent run. To lead,
triathletes should develop their ability to adapt to the specific demands of power variability
during 1 h cycling. Specific sustained interval training to overcome the high physiological and
perceptual disturbances during triathlon cycling should minimize fatigue during the cycle and
limit time lost on the subsequent run.
Conclusion
A 1 h triathlon-specific variable power cycle has a larger detrimental effect on
subsequent running performance than cycling at a constant power output with no variation in
intensity. Training to lower physiological and perceptual responses during cycling should limit
the negative effects on subsequent run performance in triathlon.
Acknowledgements
The authors would like to acknowledge Triathlon Australia for facilitating access to race power
profile information.
“Cycling Attributes that Enhance Running Performance after the Cycle Section in Triathlon” by Etxebarria N, et al.
International Journal of Sports Physiology and Performance
© 2013 Human Kinetics, Inc.
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“Cycling Attributes that Enhance Running Performance after the Cycle Section in Triathlon” by Etxebarria N, et al.
International Journal of Sports Physiology and Performance
© 2013 Human Kinetics, Inc.
Figure 1. a) A representative 10 min section of the 1 h variable power (VAR) protocol showing
five short higher intensity intervals. b) The 1 h power protocol for the variable power (VAR)
experimental trial included 30 efforts ranging between 10 to 90 s and exercise intensities
between 40 – 140% maximal aerobic power (MAP).
“Cycling Attributes that Enhance Running Performance after the Cycle Section in Triathlon” by Etxebarria N, et al.
International Journal of Sports Physiology and Performance
© 2013 Human Kinetics, Inc.
Figure 2. Four running split times (min:s) during the 9.3 km run after constant power cycling
(CON), variable power cycling (VAR) and during the run with no prior exercise (NO-EX).
Substantial differences between CON and VAR (*), VAR and NO EX (†) and CON and NO EX
(◊) during the 4 splits are represented according to the size of the standard difference and
qualitative inference (small = 1 symbol, moderate = 2 symbols). Error bars represent the 90%
confidence limits.
“Cycling Attributes that Enhance Running Performance after the Cycle Section in Triathlon” by Etxebarria N, et al.
International Journal of Sports Physiology and Performance
© 2013 Human Kinetics, Inc.
Figure 3. Correlations between the difference in B
La
(a) and RPE (b) at the end of 1 h VAR and
CON cycling and the difference in run time after VAR and CON. Dashed lines represent the
90% confidence limits.
“Cycling Attributes that Enhance Running Performance after the Cycle Section in Triathlon” by Etxebarria N, et al.
International Journal of Sports Physiology and Performance
© 2013 Human Kinetics, Inc.
Figure 4. Mean power output during the 6 s, 15 s, 30 s, 1 min, 4 min, and 10 min maximal
efforts (with proportionally increasing rest periods) during the power profile test of the current
study. The 12 race power profiles are taken from 7 different international courses involving 5
athletes and are equivalent to the maximal 5 s, 30 s, 1 min and 10 min. The 15 s and 4 min values
are the data points that best fit the curve (2
nd
order polynomial – quadratic). Data from Quod et
al. 2010 (with permission) indicates laboratory-based results for different maximal efforts as
above from 12 well-trained cyclists. Error bars represent the 90% confidence limits.
“Cycling Attributes that Enhance Running Performance after the Cycle Section in Triathlon” by Etxebarria N, et al.
International Journal of Sports Physiology and Performance
© 2013 Human Kinetics, Inc.
Table 1. Percentage difference and magnitude-based inferences between blood lactate
concentration (B
La
) at 60 min and RPE and HR at 20, 40 and 60 min of the cycle trial after CON
and VAR, all three 9.3 km experimental run times, and B
La
at the end of the three 9.3 km runs.
CL = confidence limits.
%
difference
(±90%CL)
p-value
Standardized
difference (±90%CL)
Qualitative inference
Cycle B
La
60 min
VAR - CON
147; ±26
0.00
2.01 ± 0.51 v. large
Cycle RPE
20 min
VAR - CON
-0.6; ±13.9
0.93
-0.02 ± 0.46 unclear
40 min
VAR - CON
10.2; ±8.9
0.06
0.36 ± 0.32 small
60 min
VAR - CON
25.1; ±11.6
0.00
0.79 ± 0.39 moderate
Cycle HR
20 min
40 min
60 min
VAR - CON
0.1; ±3.1
0.97
0.01 ± 0.34 unclear
VAR - CON
3.5; ±1.9
0.00
0.37 ± 0.20 small
VAR - CON
3.7; ±2.1
0.00
0.40 ± 0.23 small
9.3 km run time
VAR - CON
1.9; ±1.7
0.07
0.21 ± 0.19 small
CON - NO-EX
3.3; ±0.7
0.00
0.40 ± 0.09 small
VAR - NO-EX
5.3; ±1.7
0.00
0.63 ± 0.21 moderate
B
La
end of run
VAR - CON
11; ±25
0.40
0.31 ± 0.64 unclear
NO-EX - CON
21; ±28
0.19
0.56 ± 0.72 small
NO-EX - VAR
11; ±18
0.28
0.32 ± 0.51 small
“Cycling Attributes that Enhance Running Performance after the Cycle Section in Triathlon” by Etxebarria N, et al.
International Journal of Sports Physiology and Performance
© 2013 Human Kinetics, Inc.
Table 2. Rate of perceived exertion (RPE) on a scale of 1-10,
and B
La
responses during
the 6 s, 15 s, 30 s, 1 min, 4 min and 10 min efforts of the laboratory-based power profile test.
RPE
(units)
peak
(L.min
-1
)
B
La
(mmol.L
-1
)
6 s standing
6.8 ± 1.7
**
**
15 s
8.5 ± 1.3
**
**
30 s
9.0 ± 0.8
**
**
1 min
9.0 ± 0.9
4.2 ± 0.4
11.9 ± 3.1
4 min
8.9 ± 0.9
4.5 ± 0.6
13.0 ± 2.6
10 min
9.3 ± 0.8
4.4 ± 0.6
11.1 ± 2.0
** No measurements recorded (see methods)
(n=11)
VO
2
VO
2
