The Cycling Physiology of Miguel Indurain 14 Years After

International Journal of Sports Physiology and Performance, 2012, 7, 397-400
© 2012 Human Kinetics, Inc.
www.IJSPP-Journal.com
CASE STUDY
The Cycling Physiology of Miguel Indurain
14 Years After Retirement
Iñigo Mujika
Age-related fitness declines in athletes can be due to both aging and detraining. Very little is known about
the physiological and performance decline of professional cyclists after retirement from competition. To gain
some insight into the aging and detraining process of elite cyclists, 5-time Tour de France winner and Olympic
Champion Miguel Indurain performed a progressive cycle-ergometer test to exhaustion 14 y after retirement
from professional cycling (age 46 y, body mass 92.2 kg). His maximal values were oxygen uptake 5.29 L/min
(57.4 mL · kg–1 · min–1), aerobic power output 450 W (4.88 W/kg), heart rate 191 beats/min, blood lactate 11.2
mM. Values at the individual lactate threshold (ILT): 4.28 L/min (46.4 mL · kg–1 · min–1), 329 W (3.57 W/kg),
159 beats/min, 2.4 mM. Values at the 4-mM onset of blood lactate accumulation (OBLA): 4.68 L/min (50.8
mL · kg–1 · min–1), 369 W (4.00 W/kg), 170 beats/min. Average cycling gross efficiency between 100 and 350
W was 20.1%, with a peak value of 22.3% at 350 W. Delta efficiency was 27.04%. Absolute maximal oxygen
uptake and aerobic power output declined by 12.4% and 15.2% per decade, whereas power output at ILT and
OBLA declined by 19.8% and 19.2%. Larger declines in maximal and submaximal values relative to body
mass (19.4–26.1%) indicate that body composition changed more than aerobic characteristics. Nevertheless,
Indurain’s absolute maximal and submaximal oxygen uptake and power output still compare favorably with
those exhibited by active professional cyclists.
Keywords: detraining, performance, efficiency, reduced training
The physiological and performance characteristics
of the world’s greatest athletes are seldom reported in the
scientific literature. A very limited number of studies are
available describing the physiology of champion cyclists
at the prime of their careers,1,2 but even less is known
about the rate of decline in physiological and performance capacities of these outstanding individuals once
they retire from competition. The relationships between
physiological loss, performance decrement, and age have
been described in cross-sectional3 and retrospective4 studies of master athletes, suggesting that age-related fitness
declines are due to both aging and detraining. However,
little is known about the aging- and detraining-induced
decline of elite cyclists after retirement. Case studies of
the world’s best athletes over time are important because
they provide insight into the upper limits of human performance and the intrinsic qualities and environmental
influences that helped them reach the summit of their
sport. The purpose of this investigation was to report
on the physiological characteristics of the great cycling
champion Miguel Indurain 14 years after the end of his
professional cycling career, to gain some insight into the
aging and detraining process of elite cyclists.
The author is with the Dept of Physiology, Faculty of Medicine
and Odontology, University of the Basque Country, Leioa,
Spain.
Methods
At the age of 46, 14 years after retirement from
professional cycling, 5-time Tour de France winner
(1991–1995) and Olympic Champion (1996) Miguel
Indurain performed a progressive cycle-ergometer test
to exhaustion. Indurain gave written informed consent to
participate in the study and for publication of the results.
For the first 4 years after retirement, Indurain progressively reduced his cycling frequency from daily to
once or twice a week, never exceeding a heart rate of 165
beats/min. Thereafter, he cycled 6000 to 8000 km and
ran once a week during the warmer 6 months of the year,
but only cycled occasionally (once or twice per month)
the rest of the year. At the time of testing, he had cycled
about 8000 km over the preceding 6 months and taken
part in 2 recreational cycling events of 113 and 143 km.
He was considered to be at the peak of his annual training and fitness level. The results of the current test are
primarily compared with those of a test carried out by
the subject at the prime of his cycling career in 1994, 3
weeks before his successful attempt to break the 1-hour
cycling world record, when he had cycled ~24,000 km in
the season adding up training and competition distances.2
This comparison, however, is to be taken with caution,
as different testing equipment and protocol were used
on the 2 occasions (electromagnetically vs mechanically
braked cycle ergometer; initial load 100 W and 25-W
397
398 Mujika
increments every 3 min continuous test vs initial load
110 W and 35-W increments every 4 min with 1 min
recovery between workloads).
Indurain’s height was 1.86 m (Seca 222, Hamburg,
Germany), body mass 92.2 kg (Seca 877, Hamburg, Germany), and sum of 7 skinfolds 72.3 mm (triceps, biceps,
subscapular, supraspinale, abdominal, front thigh, medial
calf; Holtain, Crymych, UK). The incremental test was
carried out on a calibrated electromagnetically braked
cycle ergometer (Lode Excalibur Sport, Groningen, The
Netherlands) adapted with brake hoods and clip-in pedals.
Ambient temperature was 20.4°C, and relative humidity,
43.0%. Testing started at 100 W, and the workload was
increased by 25 W every 3 minutes. Cadence was kept
constant at 85 rpm, and testing continued until Indurain
could no longer maintain the required pedal rate. Gas
exchange and minute ventilations were continuously
monitored breath-by-breath using a calibrated metabolic
cart (Ergocard, Medisoft, Sorinnes, Belgium). Heart rate
was monitored throughout the trials (Polar RS800CX,
Kempele, Finland), and blood lactate measured (Lactate
Pro, Arkray Factory Inc, Shiga, Japan) from a 5-μl capillary blood sample obtained from an ear lobe at the end
of each workload.
Maximal aerobic power was determined as the highest workload maintained for 3 minutes, and maximal
oxygen uptake (VO2max) as the highest average value
obtained over a 30-second period. The individual lactate
threshold (ILT)5 and the 4-mM onset of blood lactate
accumulation (OBLA)6 were identified on the blood
lactate–power output curve. Gross efficiency was calculated at power outputs below OBLA intensity as the
ratio of power output to power input and expressed as a
percentage. Power input was determined as the rate of
energy expenditure calculated from VO2 and respiratoryexchange ratio7 measured over the final minute of each
workload. An updated table of nonprotein respiratoryexchange ratio was used to calculate the energy equivalent
of oxygen.8 Delta efficiency was calculated as the inverse
of the slope in the linear regression between the rates
of energy expended and work accomplished at power
outputs where the respiratory-exchange ratio was lower
than 1 (ie, 100–400 W).9
Results
A plateau phenomenon was observed in Indurain’s VO2
values. His maximal aerobic power was 450 W (4.88 W/
kg), VO2max 5.29 L/min (57.4 mL · kg–1 · min–1), heart
rate 191 beats/min, and blood lactate 11.2 mM (Figure
1). Submaximal power output and VO2 values at ILT and
OBLA intensities are also shown in Figure 1. The ILT
Figure 1 — Miguel Indurain’s oxygen uptake (upper left: absolute values; upper right: relative to body mass) and power output
(lower left: absolute values; lower right: relative to body mass) and their percentage change with respect to data obtained in 1994.2
Comparative ILT values are based on unpublished observations from 1995 (no oxygen-uptake values available). Abbreviations: ILT,
individual lactate threshold; OBLA, 4-mM onset of blood lactate accumulation.
Miguel Indurain’s Cycling Physiology 399
was reached at 73.1% of maximal aerobic power, 83.2%
of maximal heart rate, and 80.9% of VO2max. The OBLA
represented 82.0% of maximal aerobic power, 89.0% of
maximal heart rate, and 88.5% of VO2max. Absolute maximal and submaximal aerobic characteristics had declined
between 17.3% and 27.7% since retirement (12.4–19.8%
per decade), but the decline relative to body mass was
27.3% to 36.5% (19.4–26.1% per decade).
Power output at ILT and OBLA had declined over
the years from 79.4% and 88.3% to 73.1% and 82.0%
of maximal aerobic power, but OBLA was reached at a
similar percentage of VO2max (88.3% vs. 88.5%). The
percentage of maximal heart rate at ILT (83.5% in 1995 vs
83.2%) and OBLA (92.3-93.8% vs 89.0%) also remained
relatively stable over time.
Average gross efficiency between 100 and 350 W
was 20.1%, with a peak value of 22.3% at 350 W (Figure
2). Delta efficiency was 27.04%.
Discussion
This case study is unique in that it reports on the physiology of a retired cycling champion of the highest caliber,
and the reported values could be used as a reference for
future investigations on retired and aging athletes. The
physiological and performance characteristics of elite
endurance athletes are compromised with aging, but the
rate of decline is reduced by training.10 The observed
diminution in VO2max of 12% and 20% in absolute and
relative values per decade, respectively, indicates that
retirement was associated with a larger change in body
composition than in VO2. These values are higher than
the 10% decline per decade in relative VO2max observed
in fitness-trained former elite distance runners of similar
age.10 The higher rate of decline may be explained by the
higher competitive caliber of Miguel Indurain, his 14%
increase in body mass, the fact that his cycling training is
usually limited to 6 months of the year, and differences in
the testing protocol and equipment used. It is interesting
that while the power output at ILT and OBLA suffered a
substantial decline over the years (indicative of a reduced
training status), OBLA was reached at a similar percentage of VO2max, suggesting that there might be a steady
relationship between these 2 indices of endurance ability
in spite of aging and detraining. The same holds true for
the percentage of maximal heart rate at ILT and OBLA.
Whether these indices could be used to assess the separate
effects of aging and detraining remains to be elucidated.
Despite the observed decline, the absolute maximal
and submaximal power output and VO2 values of Miguel
Indurain are still impressive and similar to values exhibited by active male professional cyclists tested with similar protocols.9,11 Indurain’s gross mechanical efficiency
was lower than that reported for another multiple Tour
de France winner (21.2–23.1%)1 but similar to that of
competitive cyclists using comparable methods to determine gross efficiency (19.6–20.6%).7 Delta efficiency was
slightly higher than mean values reported for a group of
world-class professional cyclists at the end of a 5-year
period of training and competition (26.97% ± 3.70%).9
However, the current cycling-efficiency values should be
interpreted with caution as they may have been influenced
by the relatively short duration of the workloads (3 min)
for efficiency assessment.
In conclusion, Miguel Indurain’s absolute VO2max
and aerobic power declined by 12% to 15% per decade
over the past 14 years, whereas power at ILT and OBLA
declined by 19% to 20%. Larger declines in maximal and
submaximal values relative to body mass (19–26%) indicated that retirement was associated with a much larger
change in body composition than in absolute physiological and performance values. The current set of data does
not allow us to ascertain the differential consequences
of aging and those of detraining, but it could be used in
future investigations with that purpose. Miguel Indurain
displays at 46 years of age absolute aerobic qualities
that compare favorably with those exhibited by active
professional road cyclists.
Figure 2 — Miguel Indurain’s gross efficiency at power outputs below the 4-mM onset of blood lactate accumulation.
400 Mujika
Acknowledgments
The author would like to acknowledge the valuable comments
and suggestions provided by Prof David Pyne (Physiology,
Australian Institute of Sport).
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