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The quality of performance during international competitions such as the Olympic Games and various world championships is often judged by the number of world records attained. The simple fact that world records continue to improve is evidence that sports performance is progressing. Does this also mean that athletes are improving? Is the continual progression of world-record performances evidence that contemporary athletes are superior to the athletes who performed in the past? Technological developments may obscure insight into the athletic enhancement made by athletes over the years. This commentary tries to separate technological and athletic enhancement in the progression of world records by the use of a power balance model.
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International Journal of Sports Physiology and Performance, 2010, 5, 262-267
© Human Kinetics, Inc.
De Koning is with the Research Institute MOVE, Faculty of Human Movement Sciences, VU-University
Amsterdam, Amsterdam, the Netherlands.
World Records: How Much Athlete?
How Much Technology?
Jos J. de Koning
The quality of performance during international competitions such as the Olym-
pic Games and various world championships is often judged by the number of
world records attained. The simple fact that world records continue to improve
is evidence that sports performance is progressing. Does this also mean that ath-
letes are improving? Is the continual progression of world-record performances
evidence that contemporary athletes are superior to the athletes who performed
in the past? Technological developments may obscure insight into the athletic
enhancement made by athletes over the years. This commentary tries to separate
technological and athletic enhancement in the progression of world records by
the use of a power balance model.
Keywords: performance, modeling, innovation, athletic equipment, speed skating
At the Olympic Winter Games of 1956 in Cortina d’Ampezzo, Italy, the gold
medal in the 1500-m speed skating event was won, jointly, by the Russian skaters
Yevgeniy Grishin and Yuriy Michaylov, with a world-record time of 2:08.6. They
skated on a rink prepared on Lago di Misurina, at an altitude of 1754 m. At present,
15 Olympic Winter Games further in time, the world record has progressed (Figure
1a) and currently is held by Shani Davis from the United States in 1:41.04, skated
at the Utah Olympic Oval, Salt Lake City, Utah, at an altitude of 1423 m, in a venue
with many other world records. Is Davis really that much superior to Grishin and
Michaylov? Historical images and lm footage show that not only skating equipment
has changed, but also skating style and the intensity of racing. A part of the 27.56-s
improvement is clearly attributable to technological development. Presumably, a part
is also attributable to the athletic enhancement of the skaters. Obvious technological
improvements in speed skating include better preparation of the ice surface, aerody-
namic racing suits, and the introduction of clap skates (Dutch, klapschaats).1,2 The
effect of these technological innovations can be at least partially accounted for by
modeling with power equations, which makes it possible to estimate the inuence of
each of these improvements on performance.3,4 An adjustment of past performances
can thus be done to estimate what historical performances would be if corrected
for technological improvements. In this way, the progress of world records can be
evaluated with the current technological status as reference.
Modeling World Records 263
The Model
The velocity of a skater is related to the power produced by the athlete and the
power lost to the environment. The power produced is the aerobic and anaerobic
energy systems adjusted for the efciency of power transfer to propulsion. The
power losses consist of losses to air and ice friction as well as changes in kinetic
energy.1,4 The relation between velocity and power needed to overcome the air
frictional force is nonlinear and depends on the aerodynamics of the skaters and
their garments as well as on environmental circumstances. Studies on the aerody-
namics of speed skating1 have elicited detailed information on the effect of skating
posture, anthropometry, type of clothing, altitude, and net air motion at the venue
(eg, wind). These factors, except air motion at the venue, can be lumped together
into the aerodynamic coefcient. The relation between velocity and power to
overcome ice resistance is linear.5 Ice resistance depends on ice temperature, the
method of ice preparation, and the type of skate blade used, and is accounted for
in the coefcient of ice friction.
At a given magnitude of these coefcients, we can calculate the power demand
for any skating velocity. Taking coefcients that belong to the contemporary situ-
ation (indoor oval, high altitude, aerodynamic suits, excellent ice preparation) and
calculate the power demand to skate the world records that were set during the last
15 Olympiads (Figure 1b), we get an underestimation of the actual power output
necessary for skating each record. Technological development has reduced the
values for the aerodynamic coefcient and the coefcient of ice friction over the
years, so a correction of these coefcients needs to be done to estimate the real
power demand that belongs to each record. The altitude at which each record was
skated also needs to be taken into account. With these values accounted for, the
power output required to achieve the performances at the moment they were set
can be estimated (Figure 1c).
With historical information about the location and altitude of world record
rinks, the coefcients can be adjusted and the probable power output necessary
to skate each record can be estimated. This power output can then be used as
the basis for a recalculation of the historic 1500-m race with the power balance
model to estimate the virtual time of historic world records, as if they were skated
under the same circumstances as when the current world records were set. The
progress from the corrected world records calculated with this procedure, reect
the technology-independent enhancement that the athletes have achieved (athletic
enhancement; Figure 1d).
Technological Developments Made
During the Past 50 Years
In the 1950s and early 1960s, speed skaters were dependent on Mother Nature when it
came to ice conditions. International speed skating competitions were mainly held in
Nordic countries, the United States, or Soviet Russia, often at altitude. Although natu-
ral ice can be very fast, the absence of articial freezing made the preparation of the ice
rink unpredictable. The introduction of refrigerated 400-m ice rinks and ice resurfacing
machines reduced the coefcient of ice friction considerably (from 0.006 to 0.004)1,5.
Figure 1 — (a) Progress in world-record 1500-m speed skating for men. Vertical lines indicate technological developments. (b) Estimated power
output for the world records assuming contemporary technology and circumstances. (c) Corrected power output based on modeling results for tech-
nological developments. (d) World records corrected for technological developments.
Modeling World Records 265
A further reduction in the coefcient of ice friction (from 0.004 to 0.0035) was
made possible by the introduction of fully covered 400-m ice rinks in 1987. From
the mid-1990s, skaters had the availability of skate blades made from powdered
metallurgic material. These skate blades reduced ice friction by another 30% (per-
sonal observation), to a contemporary value of 0.0025.
In the early days, speed skaters used knitted jerseys, tightly tted pants, and
often a woolen cap. This outt was replaced in 1974 by one-piece suits made of
Lycra-like material, form tted to the body. These suits were improved in 2002
with the addition of selected smooth and rough patches for further reduction of air
frictional forces. The traditional garment caused a 10.5% larger air friction coef-
cient than the current suits, and the latest improvement caused a reduction of 2%.1
In the mid-1980s, the Dutch scientist Gerrit Jan van Ingen Schenau invented
a skate with a hinge between the boot and the blade.1,6–9 The aforementioned clap
skate is the most signicant innovation in speed skating to date. With this skate, the
athlete is able to generate a higher power output (12%) due to improved efciency
(for details, see refs. 7, 8, 9). When elite speed skaters began using this type of
skate, every world record improved at least once within the rst year of the intro-
duction of the clap skate.
Model Calculations
With the knowledge of the above-described technological developments and the
use of the power balance model, it is possible to estimate what the world records
would have been if they were all skated under the same circumstances. Figure 1a
shows the historic progress of the world records on the 1500 m; Figure 1b shows the
power output required had they been skated with contemporary technology. These
power output values are an underestimation of the power output of the skaters during
historical world-record races because not all these innovations were available at the
time of the races. Figure 1c illustrates the model estimations for the power output
that the athletes must have produced at the time of their world-record performances.
If this power output is then applied to contemporary conditions, Figure 1d would
have been the current time for the historic world records.
The progress in performance illustrated in Figure 1d could then be seen as real
athletic improvement of speed skaters over the last 15 Olympiads. This observation
suggests that roughly half of the progress in world records comes from technology
and the other half from real athletic improvement. However, published values of
muscle power output and/or VO2max in elite skaters have not changed meaning-
fully over this time period.2,10–13 Accordingly, it must be assumed that skaters have
become more efcient over the same period of time, so that the net skating power
output has increased despite little change in the biological power output. This
seems to be reasonable in terms of the increase in the amount of specic skating
training undertaken by contemporary skaters. The advent of professional teams and
the availability of year-round indoor ice rinks have massively increased the total
number of specic training hours. In the 1950s, it is likely that skaters could only
skate during 3 mo of the year (approx. 60 skating days per year, often with practices
abbreviated because of very harsh weather conditions). By 1980, with the advent
of articially cooled ice rinks, the number of skating days per year had perhaps
increased to approximately 100 per year. Contemporary skaters rarely go a week
266 De Koning
without skating and probably have >200 skating days per year. Specicity of training
is probably a critical element, as speed skating is a highly complex motor task that
must respond favorably to more specic training. The crouched position of speed
skaters has a large inuence on the blood ow and oxygenation of the leg muscles.13
Specic training could have an inuence not only on the effectiveness of motor
coordination patterns, but also on physiological adaptations. Traditionally, speed
skating was a seasonal sport with a large amount of nonspecic summer training
(running, weight lifting, plyometric exercises, and cycling). With the introduction
of refrigerated and covered skating rinks, the amount of specic training has sub-
stantially increased. In addition, short track speed skating and in-line speed skating
have become training modes and sources for an increasing talent pool. As recently
as 1990, long track speed skaters would have scoffed at the concept of skating short
track in the summer as a means of technique improvement. It can be assumed that
these developments have inuenced skating efciency positively, although historic
measurements of skating efciency are not available for comparison. However,
even the experimentally determined efciency of contemporary elite speed skaters,
values around 0.172,7 are still low compared with cycling.
The increasing speed of the skaters through the years also inuenced the skat-
ing style and racing style as well. Contemporary skaters bend their skate blades
slightly for better skating in the turns, and their race strategy has a more all-out
character. Because they are going faster, they can afford to go harder early in the
race. Accordingly, the 1500-m race has become a long sprint. The luxury of using
this all-out strategy has further contributed to the advancement of world records.
Some limitations in the way the model is used deserve mentioning. In the
presented estimations, the individual variation in skating style was not included.
Theoretically it would have been possible to include this if data on anthropomet-
ric parameters and skating position were known. Unfortunately, historic archival
material is very limited, so it is difcult to adjust the model for these factors. The
same holds for historic meteorological conditions. It must be assumed that during
all world-record performances these variables were close to optimal. However,
fans of skating can point out many examples of world records that occurred in less
than ideal climatic circumstances, which suggests that our estimation of how fast
historic athletes might have gone is still underestimated.
The corrected world records in Figure 1d show some extraordinary perfor-
mances. The world record set by Gulyayev in 1987 (1:52.70) and the world records
set by Ritsma and Koss in 1994 (1:51.60 and 1:51.29) corrected for technological
developments are performances (1:42.3, 1:42.6, and 1:42.3 respectively) in the
range expected for contemporary Olympic athletes. On the other hand, some records
set in 1997, immediately following the introduction of the clap skate, turn out to
be nonrecord performances when corrected for technological advantages. These
skaters were perhaps lucky to be the rst skaters of international level who dared
to take advantage of innovative developments. However, in high-level sports, the
courage to try innovative equipment is an admirable quality in its own right, so no
disqualifying comments are intended toward these athletes.
In summary, it can be stated that the progress in 1500-m world records during
the last 50 y can equally be attributed to technological developments and athletic
improvement. The athletic improvement represents an approximately 25% increase
in power output. However, when one considers that the increase in specic training
Modeling World Records 267
time has also increased markedly over the last 50 y and that estimates of skating
efciency are hard to correct for, it may not be unrealistic to suggest that the historic
champions would compete very effectively under contemporary conditions. The
present analysis was limited to responses in speed skating. However, we believe
that the principles presented in this commentary might allow similar correction for
historical performances in other sports.
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The present study investigates which physiological sources support the increase in mechanical power output (W out) that can be obtained using klapskates in speed skating. It was hypothesized that the increase in W out could be achieved through an increase in gross efficiency or an increase in aerobic power (W aer). Six speed skaters performed a submaximal and maximal 1,600-m skating test with both klapskates and conventional skates, to measure gross efficiency and maximal W aer during speed skating. The rate of oxygen uptake (VO2) and post-exercise blood lactate concentrations ([La]) were measured and video recordings were made. W aer was calculated from VO2. W out was derived from the power needed to overcome air and ice friction. Gross efficiency was calculated as the ratio of W out and W aer. In the maximal tests, the subjects skated faster with klapskates compared to conventional skates (10.0 vs 9.6 m x s(-1)). They sustained the resulting higher W out with klapskates with an equal VO2. [La] was, however, 1.7 mmol x l(-1) higher when klapskates were used, which might reflect an increase in anaerobic power. During the submaximal tests the skaters generated equal W out with both types of skate. Although not statistically significant, VO2 and W aer were, on average, lower when klapskates were used compared to conventional skates [mean (SD) 0.3 (0.43) l x min(-1), 105 (143) W]. Despite the lack of a statistically significant difference in W aer, gross efficiency was shown to be significantly higher with klapskates compared to conventional skates (16.3% vs 14.8%, P = 0.02). We conclude that the increase in W out when the subjects were using klapskates could be explained by an increase in gross efficiency rather than an increase in W aer.
During speed skating, the external power output delivered by the athlete is predominantly used to overcome the air and ice frictional forces. Special skates were developed and used to measure the ice frictional forces during actual speed skating. The mean coefficients of friction for the straights and curves were, respectively, 0.0046 and 0.0059. The minimum value of the coefficient of ice friction was measured at an ice surface temperature of about -7 degrees C. It was found that the coefficient of friction increases with increasing speed. In the literature, it is suggested that the relatively low friction in skating results from a thin film of liquid water on the ice surface. Theories about the presence of water between the rubbing surfaces are focused on the formation of water by pressure-melting, melting due to frictional heating and on the 'liquid-like' properties of the ice surface. From our measurements and calculations, it is concluded that the liquid-like surface properties of ice seem to be a reasonable explanation for the low friction during speed skating.
This paper attempts to clarify the formulation of power equations applicable to a variety of endurance activities. An accurate accounting of the relationship between the metabolic power input and the mechanical power output is still elusive, due to such issues as storage and recovery of strain energy and the differing energy costs of concentric and eccentric muscle actions. Nevertheless, an instantaneous approach is presented which is based upon the application of conventional Newtonian mechanics to a rigid segment model of the body, and does not contain assumptions regarding the exact nature of segmental interactions--such as energy transfer, etc. The application of the equation to running, cycling, speed skating, swimming and rowing is discussed and definitions of power, efficiency, and economy are presented.
With the use of a wind tunnel the air friction force Fw on six speed skaters of different body builds was measured. The dependence of the drag coefficient CD on air velocity v and the influence of different skating postures on drag were investigated. At an air velocity of v = 12 m/sec, an angle between upper and lower leg of 110 degrees and a horizontal trunk position, the measured air friction constant kn(=Fw/V2) of all subjects was calculated from their height l and weight m according to the formula 0.0205 l3 square root m (standard error 2%). CD and as a consequence k appeared to be strongly dependent on air velocity. Expressions to correct k for other velocities and postures were derived and substituted into a power balance by which the influence of posture, ice condition, wind and altitude on performance was predicted.
A longitudinal analysis of a group of speed skaters was done to identify the performance-determining factors for a successful speed skating career. This paper presents both the physiological and anthropometric results of this longitudinal study. Twenty-four athletes from the Dutch National Junior Speed Skating Team were followed from age 16-17 yr to age 20-21 yr. During the development from junior to senior speed skater, a number of anthropometric and physiological variables changed. There were no differences between successful and unsuccessful speed skaters from an anthropometric perspective; consequently, it was not possible to distinguish successful from unsuccessful athletes on anthropometric grounds. The longitudinal data showed that at a younger age the successful speed skaters had similar oxygen consumption, mechanical efficiency, and power output values compared with the unsuccessful speed skaters. Later in the study, successful speed skaters distinguished themselves by the ability to produce higher power output values. There were no anthropometric or physiological relationships found in this study on which performance at the age of 20-21 yr could be predicted with measurements at a junior age.
To prevent the tip of the blade from scratching through the ice, the technique in speed skating requires that plantar flexion is largely suppressed during the gliding push off. This not only prevents the plantar flexors from contributing to external work but also causes the skater to lose contact with the ice long before the knee is fully extended. To prevent these disadvantages of the gliding technique, a new skate was developed that permits the shoe to rotate relative to the blade in a hinge between shoe and blade. In a case control study the progression between the 1993/1994 and 1994/1995 skating seasons of 11 male skaters from a regional junior selection who consented to switch to this new skate was compared with the progression of 72 skaters of this and all other regional and national male junior selections of The Netherlands. The experimental group appeared to improve their personal best times by 6.2 +/- 2.3%, which is a significantly (P < 0.001) larger progress than the 2.5 +/- 1.6% improvement of the control group. The new skate will therefore most likely add a new dimension to the art of speed skating.
We have previously hypothesized restricted muscle blood flow during speed skating, secondary to the high intramuscular forces intrinsic to the unique posture assumed by speed skaters and to the prolonged duty cycle of the skating stroke. To test this hypothesis, we studied speed skaters (N = 10) during submaximal and maximal cycling and in-line skating, in both low (knee angle = 107 degrees) and high (knee angle = 112 degrees) skating positions (CE vs SkL vs SkH). Supportive experiments evaluated muscle desaturation and lactate accumulation during on-ice speed skating and muscle desaturation during static exercise at different joint positions. Consistent with the hypothesis were reductions during skating in VO2peak (4.28 vs 3.83 vs 4.26 L x min(-1)), the VO2 at 4 mmol x L(-1) blood lactate (3.38 vs 1.93 vs 3.31 L x min(-1)), and cardiac output during maximal exercise (33.2 vs 25.3 vs 25.6 L x min(-1)). The reduction in maximal cardiac output was not attributable to differences in HRmax (197 vs 192 vs 193 b x min(-1)) but to a reduction in SVmax (172 vs 135 vs 134 mL x beat(-1)). The reduction in SV appeared to be related to an increased calculated systemic vascular resistance (354 vs 483 vs 453 dynes x s(-1) x cm(-1)). During maximal skating there was also a greater % O2 desaturation of the vastus lateralis based on near infrared spectrophotometry (50.3 vs 74.9 vs 60.4% of maximal desaturation during cuff ischemia). The results were supported by greater desaturation with smaller knee angles during static exercise and by greater desaturation and accelerated blood lactate accumulation during on-ice speed skating in the low vs high position. The results of this study support the hypothesis that physiological responses during speed skating are dominated by restriction of blood flow, attributable either to high intramuscular forces, the long duty cycle of the skating stroke, or both.
The development of the new skate design specifically the klapskate in a historical and scientific perspective is described. Reasons why it took so long for top athletes to use the new skate design is explained. The klapskate demonstrated its advantage over conventional skates and proved its benefits.
Reducing ice friction was one of the motives for developing the klapskate. However, the magnitude of power dissipation that occurs with conventional skates when a skater plantar flexes his ankle and the tip of the blade is pressed into the ice has not been quantified previously. In this study, we examine how ice friction varies during a single stroke with conventional skates and estimate the reduction in ice friction that might be obtained with klapskates. Five elite speed skaters performed a series of trials at constant velocity and a series of maximal accelerations. Energy dissipated to ice friction during a stroke with conventional skates was analyzed using an instrumented skate and high-speed 3D kinematic analysis. The energy that would be dissipated when klapskates were used was estimated from the collected data with conventional skates. The estimated difference in power loss between conventional and klapskates was less dramatic than has been suggested frequently. Pressing the tip of the blade into the ice comprises only 0.84 W of the total power dissipated by ice friction (54 W) during constant velocity speed skating. During an all-out acceleration, this power loss reached 4.55 W. We conclude that only a minor part of the benefit of klapskates can be attributed to a reduction in ice friction. It is shown that this relatively small increase in ice friction is related to the large length of the skate blade.