Percent utilization of V̇O2 max at 5-km competition velocity does not determine time performance at 5 km among elite distance runners

Abstract

The present study investigated to what extent maximum oxygen uptake (VO2 max) and fractional utilization (%VO2 max) in 5-km competition speed correlate with 5-km performance times among elite long distance runners. Eight elite long distance runners with 5-km performance times of 15.10 minutes ( +/- 32 seconds) were tested for VO2 max during an incremental protocol and for %VO2 max during an 8-minute treadmill test at the velocity representing their 5-km seasonal best performance time. There was no correlation between fractional utilization and 5-km performance. The study showed no significant difference between VO2 max obtained during an incremental VO2 max test and %VO2 max when running for 8 minutes at the runner's individual 5-km competition speed. The 5-km time was related to the runner's VO2 max even in a homogenous high-level performance group. In conclusion, the present study found no relationship between fractional utilization and 5-km performance time. Training aiming to increase %VO2 max may thus be of little or no importance in performance enhancement for competitions lasting up to approximately 20 minutes.

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NUMBER 1OF1
AUTHOR QUERIES
DATE 2/27/2010
JOB NAME JSC
ARTICLE 201068
QUERIES FOR AUTHORS Støa et al
THIS QUERY FORM MUST BE RETURNED WITH ALL PROOFS FOR CORRECTIONS
AU1) Please provide the middle initials (if any) for the authors ‘‘Øyvind Støren’’, ‘‘Eystein Enoksen’’
and ‘‘Frank Ingjer’’.
AU2) Is this correct at the very end of the ref list?

PERCENT UTILIZATION OF
_
VO
2
MAX AT 5-KM
COMPETITION VELOCITY DOES NOT DETERMINE
TIME PERFORMANCE AT 5KMAMONG ELITE
DISTANCE RUNNERS
EVA MARIA STØA,
1,2
ØYVIND STØREN,
1
EYSTEIN ENOKSEN,
2
AND FRANK INGJERAU1
2
1
Telemark University College, Department of Sport and Outdoor Life Studies, Bø, Norway; and
2
Norwegian School of Sport
Sciences, Oslo, Norway
ABSTRACT
Støa, EM, Støren, Ø, Enoksen, E, and Ingjer, F. Percent
utilization of _
VO
2
max at 5-km competition velocity does not
determine time performance at 5 km among elite distance
runners. J Strength Cond Res 24(x): 000–000, 2010—The
present study investigated to what extent maximum oxygen
uptake ( _
VO
2
max) and fractional utilization (% _
VO
2
max) in 5-km
competition speed correlate with 5-km performance times
among elite long distance runners. Eight elite long distance
runners with 5-km performance times of 15.10 minutes ( 632
seconds) were tested for _
VO
2
max during an incremental
protocol and for % _
VO
2
max during an 8-minute treadmill test
at the velocity representing their 5-km seasonal best perfor-
mance time. There was no correlation between fractional
utilization and 5-km performance. The study showed no
significant difference between _
VO
2
max obtained during an
incremental _
VO
2
max test and % _
VO
2
max when running for 8
minutes at the runner’s individual 5-km competition speed.
The 5-km time was related to the runner’s _
VO
2
max even in
a homogenous high-level performance group. In conclusion, the
present study found no relationship between fractional
utilization and 5-km performance time. Training aiming to
increase % _
VO
2
max may thus be of little or no importance in
performance enhancement for competitions lasting up to
approximately 20 minutes.
KEY WORDS aerobic capacity, fractional utilization, long
distance running
INTRODUCTION
Long distance running represents distances from
1500 m to ultra marathon. During a 5-km
competition the anaerobic energy expenditure is
responsible for only about 10% of the total energy
expenditure, whereas the aerobic capacity is one of the most
important variables predicting 5-km running performance
(22,27). Maximum oxygen uptake ( _
VO
2
max) represents the
runner’s aerobic capacity and is thus an important de-
terminant of success in distance running (11,15,21).
Previous studies have reported strong correlations bet-
ween long distance performance time and _
VO
2
max (25,27).
However, _
VO
2
max has previously not been shown to predict
race performance in long distance running among runners at
a homogenous _
VO
2
max level (6,7). In a model described
by Pate and Kriska (21), 3 major factors account for
interindividual variance in aerobic endurance performance—
maximal oxygen uptake ( _
VO
2
max), lactate threshold (LT),
and work economy (C). This is in accordance with several
other studies (4,7,9,10,22). Consequently, the runner with the
highest _
VO
2
max, who is able to utilize the highest fraction of
the maximal oxygen uptake for an extended period of time
and with the lowest O
2
cost of running per meter, will most
probably win the competition. In addition to the perfor-
mance-predicting factors mentioned, several studies have
shown that high-level runners are able to utilize a large
fraction of the maximal oxygen uptake for an extended
period (6,9). Le
´ger et al (20) have shown that the correlation
between fractional utilization (% _
VO
2
max) and performance is
dependent on the running time in competition rather than
the running distance. Among world class runners, personal
best 5-km times vary from 12.38 minutes to 13.10 minutes
(13). Based on results from the Norwegian Championships in
2005, runners at a Norwegian national level have personal
best times ranging from 13.40 to 15.50 minutes.
_
VO
2
max is shown to be the physiological variable that
correlates best with performance in competitions lasting
between 4 and 10 minutes, whereas % _
VO
2
max becomes in-
creasingly more important with distance from approximately
Address correspondence to Assistant Professor Eva Maria Støa, eva.m.
stoa@hit.no.
0(0)/1–7
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Ó2010 National Strength and Conditioning Association
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10 km (5,8,19,23). According to Joyner and Coyle (16), the
best marathon runners are those who are able to maintain
a high % _
VO
2
max during the whole competition.
According to Davies and Thompson (8), % _
VO
2
max in 5-km
competition among national-level runners ranges from 92%
to 98% _
VO
2
max. Other studies indicate that the best runners
at this distance have the ability to utilize 100% of their
_
VO
2
max, meaning that they are able to complete the whole
distance at an intensity equal to their _
VO
2
max (8,17). The
5-km world record is 12.37.35 (13). According to A
˚strand
and Rodahl (27), an intensity representing 100% _
VO
2
max
can be maintained for approximately 15 minutes among
elite athletes, indicating that elite runners can race 5 km at
approximately _
VO
2
max. For distances longer than 5 km, the
speed will represent a certain percentage of the runner’s
_
VO
2
max. This % _
VO
2
max should, according to Le
´ger et al
(20), decrease in accordance with the longer time spent in
these competitions.
Only a few studies have investigated the relationship
between 3-km or 5-km running performance and fractional
utilization (8,18,24,). Only the study by Lacour et al (18) is
performed on high-level 5-km runners. The aims of the
present study thus were to explore to what extent maximum
oxygen uptake ( _
VO
2
max) and fractional utilization (% _
VO
2
max)
in 5-km competition speed correlate with 5-km performance
times among long distance runners at a national level and to
investigate if there is a significant difference between _
VO
2
max
and % _
VO
2
max at 5-km competition speed. The hypothesis
was that high-level runners are able to utilize close to 100%
of their _
VO
2
max during a 5-km competition and that
%_
VO
2
max utilized at competition speed is a function of time
rather than distance.
METHODS
Subjects
A group of 8 runners attended this study. All subjects signed
a consent paper approved by the local Human Research
Ethics Committee at the Norwegian School of Sports
Sciences. The paper informed the subjects about the experi-
mental risks and stated that the participation was voluntary
and that they could withdraw from the study without further
explanation. The subjects were regarded as elite runners,
regularly competing on the 5-km distance at a national level,
and they all had a 5-km personal best between 14.26 and 15.50
minutes on track. Running velocity among the subjects is on
average 16% slower than the 5-km world record velocity on
track. The runners in this study were regularly competing at
a national level in either track or field. Three of the runners
were competing at an international level. Their weekly
running kilometer total ranged from approximately 120 to
200 km. They were all tested in their competition season.
All the runners were familiar with running on a treadmill,
and they all had performed _
VO
2
max tests earlier in their
running career. All the runners were thoroughly informed of
the test procedure.
The last days before testing, the runners were told to eat
as normal. Their diets were therefore similar to normal
competition preparation; this is important because the
purpose of the study is to compare the test results with
competition results. All the runners followed a standard
procedure concerning hydration and food intakes before
testing. This procedure implied not eating 2 hours before
testing and not drinking anything other than water within
2 hours before testing.
The subjects’ characteristics are presented in T1Table 1.
Test Procedures and Material
The first test was a standard incremental _
VO
2
max test, as
previously described in Støren et al (26). In this study, a 1.7%
treadmill inclination was used. This inclination is a compen-
sation for air resistance during competition. The velocity at
the beginning of the test was equal to the runner’s individual
lactate threshold velocities. The speed increased by 1 kmh
each minute for the first 3 minutes, and for each following
minute the runner was asked before further increasing
the speed. _
VO
2
(mlkg
21
min
21
) was measured continuously
and the heart rate was taken every 30 seconds. The test
continued up to voluntary exhaustion. In addition, at least
1 of the following criterion was achieved among the runners:
stagnation or reduced oxygen uptake despite increasing
velocity, respiratory quotient $1,10, or heart rate $97 %
HFmax. _
VO
2
max was set to the average of the 2 highest
following _
VO
2
measurements.
According to several studies (11,12,14,15), a velocity that
will exhaust the runner between 4 and 6 minutes is an
accurate workload to reach _
VO
2
max. All the runners in this
study reached voluntary exhaustion between 4 and 6 minutes.
A second test was made to measure the specific % _
VO
2
max
at an individual 5-km velocity (3). According to Bernard et al
(3), when measuring variables concerning a specific distance,
the velocities under testing should reflect the true race
intensity. _
VO
2
data should also be measured at specific
steady-state competition intensity. The methods used to
discover % _
VO
2
max among distance runners vary in previous
studies, and it seems like there is no standard method to find
%_
VO
2
max in long distance running. However, several studies
TABLE 1. Physical and performance characteristics
of runners (n= 8).
Variables
Age (years) 29 62.9
Weight (kg) 66.5 65.8
Height (cm) 178 63.4
Time 5 km (min) 15.02 60.53
Values are mean 6SD.
2
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suggest that the most specific method to measure % _
VO
2
max
is to collect _
VO
2
data when running at the velocity
representing average competition speed at the given distance
(3,24).
Bernard et al (3) have shown that it takes longer time to
reach _
VO
2
steady state during maximal, compared to sub-
maximal, intensities. The % _
VO
2
max test in this study implied
running for 8 minutes at the runner’s individual average 5-km
competition velocity. Because the velocity during this test
represents the runners’ 5-km competition speeds, all the
runners are above lactate threshold (
T3 Table 3). This test is
thus not a measurement of efficiency or running economy
because running economy measured as oxygen cost of
running should be measured at submaximal intensities,
preferably below lactate threshold (9).
The % _
VO
2
max test lasted for 8 eight minutes. The velocity
was calculated from the runner’s individual average velocity
during the present season’s personal best 5-km performance.
After a standard warm-up, the runners had 30 seconds to
reach competition speed, whereupon the test was started.
Both _
VO
2
and heart rate were measured continuously during
the test. The % _
VO
2
max was calculated on the basis of the
average of the 4 highest following _
VO
2
values at steady-state
measurements between 4 and 8 minutes. All the subjects
achieved a steady-state _
VO
2
between the fifth minute and the
eighth minute.
Each test was carried out on 2 different days, with a
minimum of 2 and a maximum of 7 days with easy training in
between the tests. A pilot study was done prior to the
study, and no test-to-test variation concerning _
VO
2
or lactate
measures was observed between the 2 studies.
Equipment
A Woodway PPS 55sport treadmill (Germany) calibrated
for inclination and speed was used for all running tests. _
VO
2
was measured using the metabolic test system Oxycon
Champion (Jaeger-Toennies, Wurtzburg, Germany). All test
Figure 1. The relationship between maximal oxygen uptake ( _
VO
2
max,
mlkg
20.75
min
21
) and 5-km running personal best (minsec). R
2
= 0.684,
p,0.05.
TABLE 2. Physiological results (n= 8).
Variables
_
VO
2
(mlkg
21
min
21
)
_
VO
2
(mLkg
20.75
min
21
)
HR
(beatsmin
21
)La
2
(mmolL
21
)R%
_
VO
2
max(mlkg
20.75
min
21
)
%_
VO
2
max
(mlkg
21
min
21
)
_
VO
2
max intensity 73.1 64.7 207.9 614.0 186 66 7.9 61.2 1.16 60.04 100 60.0 100 60.0
5-km race intensity 71.5 65.8 203.8 616.1 182 66* 6.7 61.5* 1.05 60.04†98.0 63.7 97.3 62.6
Values are mean 6SD._
VO
2
max = maximal oxygen uptake; _
VO
2
= oxygen uptake; HR = heart rate; La
-
= lactate; R = expiratory CO
2
/_
VO
2
.
*p,0.05.
†p,0.01, significantly different from _
VO
2
max intensity values.
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equipment underwent a standard calibration procedure on
each test day before the testing procedures were carried out.
These calibration procedures are standards at the Exercise
Physiology Laboratory (Norwegian School of Sports Scien-
ces). _
VO
2
values were obtained from a mixing chamber every
30 seconds. Generally, test-to-test variations in _
VO
2
max
measurements have a variability of 63% (27). However, tests
at our laboratory have shown test-to-test variations of less
than 1%.
Lactate measurements were performed using an YSI 1500
Sports Lactate analyzer (Yellow Springs Instruments Co.
Yellow Springs, OH, USA). HR was measured using Polar
s610 heart rate monitors (Polar, Kempele, Finland).
Allometric Scaling
Energy cost for movement does not increase in the same rate
as body weight. According to Bergh et al (2) and Helgerud
(11), comparisons of _
VO
2
max should be expressed relative
to body mass raised to the power of 0.75 when running.
_
VO
2
values are thus mainly expressed in mlkg
20.75
min
21
in
the present study.
Statistical Analyses
In all cases, p#0.05 was taken as the level of significance
in 2-tailed tests. Descriptive statistical analysis was made to
display means and standard deviations (SD). To compare
means, paired T-tests and independent samples T-tests were
used. The data were tested for normal distribution using
quantile—quantile (QQ) plots. Correlations were calculated
by the Pearson correlation test.
Blood Samples
Blood samples were taken from fingertip immediately after
both tests. Before each test, the lactate analyzer was calibrated
with the use of a standardized lactate solution of 5 mmolL
21
.
The linearity for higher lactate values was also controlled for
by the use of a standardized 15 mmolL
21
lactate solution.
According to the user manual for the YSI 1500 Sports
Lactate analyzer, the variability of measurements are 62%
at lactate values between 0 and 5 mmolL
21
and 63% at
lactate values between 5 and 15 mmolL
21
.
Weight
All the runners were weighed wearing running shoes, a t-shirt,
and running shorts/tights at a digital Seca weight (Seca,
Hamburg, Germany) before testing.
TABLE 3. Individual physiological results.
Subject no. 1 2345678
Time performance (minsec) 14.26 14.30 14.33 14.50 14.59 15.30 15.32 15.50
_
VO
2
max (mlkg
20.75
min
21
) 219.4 221.6 210.9 221.9 210.0 200.8 182.3 196.6
%_
VO
2
max 100 98.4 97.9 92.7 98.5 93.8 98.3 99.0
[La
-
]
b
(mmolL
21
) 5.3 6.3 5.9 9.5 8.3 5.5 6.4 6.3
_
VO
2
max = maximal oxygen uptake; [La
2
]
b
= blood lactate concentration after % _
VO
2
max test.
Figure 3. The relationship between time of running and fractional
utilization (% _
VO
2
max). Figure shows results from Lacour et al, Støa et al,
Davies and Thompson, Ramsbottom et al (1987), and Ramsbottom et al
(1992).
Figure 2. Comparison of physiological results at 5-km race intensity and
at _
VO
2
max intensity in percent of _
VO
2
max. *p,0.05. **p,0.01.
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RESULTS
Relationship Between _
VO
2
max and 5-km Performance
The subjects’ average _
VO
2
max was 73 (64.7) mlkg
21
min
21
and 207.9 (614) mlkg
20.75
min
21
. The results showed
a strong correlation between performance and _
VO
2
max
(R
2
= 0.752 and 0.684, respectively) as presented inF1 Figure 1.
Relationship Between Fractional Utilization (% _
VO
2
max) and
5-km Performance
The average O
2
expenditure of the subjects’ competition
speed was 71.5 mlkg
21
min
21
and 203.8 mlkg
21
min
20.75
.
The mean values for _
VO
2
max were 73.1 mlkg
21
min
21
and
207.9 mlkg
21
min
20.75
, which gives an average of 97.3 and
98% _
VO
2
max. The results showed no correlation between
fractional utilization and 5-km performance (T2;T3 Tables 2 and 3).
Eight Minutes Running at the Runner’s Individual 5-km
Competition Speed
No significant difference was seen between _
VO
2
max and the
O
2
expenditure (fractional utilization) during 8 minutes of
running at the runner’s individual 5-km competition speed.
The [la
2
]
b
, HR, and R were found to be 16%, 2%, and 9%
lower after the fractional utilization test compared to the
_
VO
2
max test (F2 Figure 2, Tables 2 and 3).
DISCUSSION
The major findings in this study are that % _
VO
2
max does
not correlate with 5-km performance and that the results
revealed no significant difference between the runners’
_
VO
2
max and their oxygen expenditure during an 8-minute
test at their individual 5-km competition speed. The finding
in this study support previous studies indicating that
%_
VO
2
max is a consequence of time rather than distance
and that % _
VO
2
max can not predict performance at distances
up to and including 5 km.
Time performance in running is mainly a function of
3 factors: _
VO
2
max, running economy, (RE) and LT (21).
According to Bassett and Howley (1) and Joyner and Coyle
(16), fractional utilization is an important factor influencing
running performance irrespective of distance and time spent
in competition. In opposition to this, it is argued that
fractional utilization is merely a consequence of time spent in
competitions, at least regarding distances up to and including
5 km (5,8,20,23). In a heterogeneous time performance
group of runners, those with the best _
VO
2
max and the best
RE will complete a given distance in a shorter time than
those with poorer _
VO
2
max or RE. Consequently, the runners
that complete the distance in the shortest time will be able to
run at the highest individual intensity and thus show the
highest fractional utilization of _
VO
2
max. In a homogenous
time performance group of runners, the runners complete
a given distance in approximately the same time. Conse-
quently, these runners will show approximately the same
fractional utilization of _
VO
2
max. The results of this study
support the latter, indicating that % _
VO
2
max does not predict
running performance among high-level runners at a 5-km
running competition.
Fractional Utilization at Competition Speed
The present study revealed no significant difference between
the _
VO
2
measurements during the fractional utilization test
and the _
VO
2
max test. This implies that these runners during
a 5-km competition perform at an intensity equivalent to
_
VO
2
max. Consequently, the runner’s individual _
VO
2
max level
should have a strong influence on performance.
Relative Importance of _
VO
2
max in 5-km Performance
The results in this study showed a close negative relationship
between the runners’ _
VO
2
max and performance times (R
2
=
0.684), although the runners were characterized as a homog-
enous group of runners. _
VO
2
max should thus explain 68% of
interindividual variance in performance times. We may
speculate that these elite long distance runners after many
years of running have accomplished close to similar RE and
therefore much of the variation in performance times could
be related to the differences in the runners’ _
VO
2
max. How-
ever, RE was not examined among the subjects participating
in this study.
Relationship Between Fractional Utilization and Competition
Time
Several studies have shown that % _
VO
2
max among runners
decrease proportionally with increasing time of running
(5,8,20,23). These findings may indicate that the lower
%_
VO
2
max among the runners in the studies of Ramsbottom
et al (23) and Davies and Thompson (8), compared with the
present study, is reflected by the lower performance level of
the runners and consequently their longer time spent in
competition compared with the runners in this study. The
Figure 4. The relationship between time of running and corrected
fractional utilization (% _
VO
2
max). Figure 4 shows results from Lacour et al,
Støa et al, Davies and Thompson, Ramsbottom et al (1987), and
Ramsbottom et al (1992) and are corrected by the formula of Le
´ger et al:
Y = 126.69 – 11.056 ln X.
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connection between time of running and % _
VO
2
max has
been systemized by Le
´ger et al (20) by the following
equation: Y = 126.69 – 11.056 ln X (r=20.936 ).When
calculating the results from the present study and from the
studies of Ramsbottom et al (23), Lacour et al (18), and
Davies and Thompson (8) with the formula of Le
´ger et al
(20), the measured % _
VO
2
correspond closely to the % _
VO
2
estimated by the formula. This finding is thus in accordance
with studies suggesting that % _
VO
2
is a poor predictor of
performance at shorter long distances (1,500 m–5,000 m), but
is of gradually greater importance with increasing distances
from 10 km (5,8). The present results accompanied with
previous results (8,18,20,23) are presented in
F3;F4 Figures 3 and 4.
The relationship between time of running and fractional
utilization as shown by the formula of Le
´ger et al (20) can
be illustrated by the following example: If 2 runners at
different performance levels run as fast as they can for
10 minutes, the runners will have similar % _
VO
2
max. The
best runner will naturally cover the longest distance and
thus have the best performance. Because they have similar
%_
VO
2
max, this achievement must be a result of another
factor than the fractional utilization. Most likely, the better
performance is a result of a higher _
VO
2
max and/or a better
running economy, as discussed in Pate and Kriska (21).
Further research on this topic should therefore contain
additional measurements of RE, maximal aerobic speed
(MAS), and LT.
PRACTICAL APPLICATIONS
The major finding in this study is that fractional utilization
(% _
VO
2
max) does not correlate with 5-km performance
among elite distance runners. There was no significant
difference between the runners’ _
VO
2
max and their oxygen
expenditure during an 8-minute test at individual 5-km com-
petition speed. The runners’ _
VO
2
max were closely correlated
to performance time.
Because % _
VO
2
max did not correlate with performance in
this study, the differences in performance level among the
runners must be the result of another factor than the
fractional utilization. Most likely, the better performance is
a result from a higher _
VO
2
max and/or a better running
economy, as discussed in Pate and Kriska (21). Generally, to
improve 5-km performance time, the runner should thus
focus on improving _
VO
2
max and RE. This may be achieved
by high-intensity aerobic interval training (12) and maximal
strength training (26). When improving these 2 factors, the
runner will run faster and consequently utilize a higher
percentage of _
VO
2
max during competition.
Based on the results from the present study, we suggest that
the physical variable fractional utilization of maximal oxygen
consumption (% _
VO
2
max) should not be considered a perfor-
mance determinant in short long distance running (duration
up to approximately 20 min). Training aiming to increase
%_
VO
2
max may thus be of little or no importance in
performance enhancement for competitions lasting up to
approximately 20 minutes.
ACKNOWLEDGMENTS
There is no conflict of interest.
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