Improving Athletic Performance or Promoting Health through
Professor Timothy David NoakesDiscovery Health Chair of Exercise and Sports Science and Director MRC/UCT
Research Unit for Exercise Science and Sports Medicine
Division of Human Structure and Function
University of Cape Town
Sports Science Institute of South Africa
P O Box 115, Newlands, 7725, South Africa.
IntroductionThe Twentieth Century saw a massive growth in the extent to which sport and physical activity impacted on the lives of many of the world's populations. In part this has been due to the progressive internationalisation, professionalisation and commercialisation of a group of sports, including football, track and field athletics, rugby, and cricket which developed in England in the latter half of the nineteenth century, and their evolutionary offshoots in North America including baseball, American football and basketball. Since its foundation more than 100 years ago, the Olympic movement, which began as a largely Eurocentric organisation, has also expanded the reach of an additional diverse range of sports to all the corners of the >world.
One effect of the growth of international sport has been the quite spectacular expansion in the supporting medical disciplines, sports medicine and the exercise sciences. Knowledge acquired in these disciplines has increased our understanding of how the body adapts to training, in both healthy and unhealthy ways, and which bodily factors determine athletic abilities. An important offshoot has been the research into the mechanisms by which regular physical activity improves longevity and reduces the risk that certain diseases will develop, as reviewed by Professor Haskell in his presentation.
In this lecture I wish to discuss what effect the globalisation of sport has had on human athletic achievements; what explains those changes and what bodily (physiological) factors probably set the limits for human athletic performance. This sets the scene also to ask the question: Should we be promoting sport and physical activity to improve athletic performance or, alternatively, to promote health? The point I shall be making is that the two are not necessarily complimentary.
For whereas the promotion of physical activity potentially involves all the world's people, superior athletic performance is the province of only a tiny fraction of uniquely gifted humans both in terms of inherited genetic factors and the financial resources to provide the necessary supportive environment. Perhaps, just as the 20th century produced a remarkable growth in competitive sport across the globe, spearheaded not least by the Olympic Movement, so the 21st century will witness the next important development - a rise in the use of recreational physical activity to promote health on a global scale.
Improving athletic performance
Improvements in human athletic performance in the 20th centuryThe past century has witnessed a progressive, indeed remorseless improvement in human athletic performance. This is most apparent in track and field, a sport the records of which were first established about 120 years ago.
Thus during the first 70 years of the 20th
century, record performances in the 100m improved at a relatively constant rate
of 0.6 m/min/year in the 100m and at 0.9 m/min/year in the marathon. Only
in the past 30 years has it become apparent that in some events including the
1500m, the rate of progress is no longer as rapid as it was between 1900 and 1950,
suggesting that humans are gradually approaching some physiological limits for
their performances, at least in track and field events (Noakes, 1992).
Possible factors explaining the progressive improvement in human athletic performance during the 20th century.* Increased training loads
When the English runner, Alf Shrubb, set >world running records for distances from 1 - 11 miles between 1900 and 1904, he trained about 67 km per week of which 22 km were at race pace. In contrast, the peak training of a modern Kenyan 5000-10 000m runner would cover about 230 km weekly for about 6 weeks before a major international competition. Most of this training is undertaken at medium altitudes (~2000m) at speeds barely comprehensible to non-Kenyans. It is perhaps not surprising that this modern Kenyan athlete would be able to run at least 10 km (6.2 miles) at a speed that Alf Shrubb could sustain for less than 1/6th of that distance.
However this increased training volume is not without risk; the probability that the athlete will do too much and so develop a fatigued state, known as the overtraining syndrome, is high. This condition was barely recognised in Alf Shrubb's era or indeed before about 1960, but has become an increased concern in modern sport. Particularly concerning are the risks, still unknown, of exposing young adolescents to the extreme demands of heavy training for international competition from a young age. The dangers are as much psychological as physical. Such training may rob the child of the chance to be a child.
But of equal concern are reports of the long-term physical effects of daily training of high volume or high intensity, or both, sustained for 10-20 years. Athletes at particular risk are marathon runners and triathletes of >world-class. Early reports suggest the development of a syndrome of premature skeletal muscular ageing with, in some cases, profound exercise intolerance and associated mental changes. It is paradoxical that those who are the most vibrant in their youths may suffer this unacceptable consequence.
Even the Kenyans are not exempt from the consequences of their heavy training and the intensive competition from their peers. With the result that few Kenyans survive at the top of their sport for more than a couple of years.
* Increased global participation
When the first modern Olympic Games were held in Greece in 1896, athletes from a total of 13 countries participated. Even for the first 20 years of the twentieth century, the Olympic Games were essentially a Eurocentric and North American festival with limited participation of athletes from Asia, Africa and South American countries. Only by mid-century were more than 50 countries regularly represented at the Games.
In 1968 three significant events occurred that would profoundly influence future Olympic competitions and the nature of international sport in the last 30 years of that century and thereafter.
First was the participation, for the first time of athletes from the German Democratic Republic (GDR) competing as a separate country, in the 1968 Olympic Games. The result was that between 1968 and 1988, athletes from the GDR became a dominant force in international Olympic and other competitions winning a similar number of Olympic medals as athletes from the United States of America. For example, the number of medals won by the GDR increased from 25 in 1968 to 128 in 1980 (when the United States did not compete) and to 102 in 1988, one more than the total medal count of the United States athletes. In the 1976 Olympic Games, athletes from the GDR won 40 gold medals compared with only 34 by athletes from the United States.
When one considers that the population of the GDR during those years was less than 20 million or approximately one tenth that of the United States, the true magnitude of this achievement is apparent. Whilst ethical doubts about the basis for that success persist and may be answered in the legal proceedings currently in progress against the former head of GDR sport, Manfred Ewald, yet it was unquestionable these successes that stimulated other countries most especially the USA and Australia, to professionalise the scientific and medical support provided to their athletes, along the lines first pioneered by the GDR sports system.
The driving logic was that if the East Germans could do it, why not the Americans or Australians, or indeed the athletes from any country choosing to adopt this philosophy and approach? All that was required was to discover “the secret”. And in as much as science might provide that “secret”, so the idea dawned that possibly science could play a role in promoting athletic success and the resulting international prestige that flowed from this success.
The second factor was holding the 1968 Olympic Games in Mexico City. For Mexico City is sited at an altitude of 2270m. And never before had the Olympic Games been held at a venue so high above sea level.
This single fact first exposed, on an international scale, the very real and quite embarrassing inadequacies in the depth of knowledge in the exercise sciences at that time. For in addition to a great depth of ignorance in many other areas, the real effects of medium altitude on athletic performance were simply not known. For example, no one knew whether it was possible to hold such high quality competition at altitude without endangering the lives of the competitors.
The result was that every major sporting country with the capacity to undertake scientific research in this field immediately established exercise at altitude as an urgent research priority.
This research showed that whereas performance improved with residence at altitude, the time it would take for full acclimatization was a “matter of months rather than weeks”. There would be no great performances at the Mexico City Games from athletes who had been born and who had lived and trained at sea level.
In the end the results were as the scientists had predicted; the endurance events in running were dominated by athletes who resided at altitude, especially those from East Africa. Sir Roger Bannister’s statement, that it would take a lifetime for an athlete born at sea level to adapt for maximum exercise at medium altitude, was proved correct.
As a result, it was the 1968 Olympic Games in Mexico City that heralded the modern re-awakening of international sports medicine and sports science. It was the singular event that stimulated the remarkable growth in these disciplines in the last 30 years of the 20th century.
The third event was the performances of the East African, especially Kenyan athletes at those games. Most spectacular was the performance of Kip Keino who defeated American >world record holder Jim Ryun in one of the greatest 1500 races in the history of the Olympic Games. This event heralded the arrival of the second great wave of athletes from the African continent who would rise to dominate another segment of >world athletics.
Current analysis shows that superior athletic performances in track and field events are geographically based. Thus athletes whose genetic origins are in Central West Africa dominate running distances from 100 - 400m as well as the long jump, whereas East, North and South African athletes dominate the longer races of 5 - 42 km. European runners, especially Russians, are increasingly dominant at racing distances beyond 80 km. These findings suggest that not all of the >world’s populations have equal athletic ability; a contentious opinion for which there does appear to be a strong body of evidence (Noakes, 1999; Entine, 2000).
The point of this analysis is to show that it is only when a particular sport becomes truly global that those humans with the unique abilities necessary for success in that sport, are likely to be included. Only then will the true human sporting potential in the different athletic disciplines become apparent.
Hence greater global participation will increase the probability that the small number of exceptionally gifted humans able to achieve superior performances, will be included in any particular sporting activity.
* Scientific and technological innovations
The rise of the sports science stimulated by the 1968 Olympic Games, has increased the understanding of the physiology of the human body and how it adapts to training. This has improved the quality of the advice that is given to athletes. Athletes are now more likely to follow advice that works and the probability that erroneous practices will be adopted, has been reduced.
My analysis of many generations of accumulated coaching wisdom and the experience of the best runners of the past century suggests that at least 15 Laws of Training can be identified (Table 1). The more widespread application of this knowledge would explain at least part of the continued improvements in athletic performance in the past 20 years.
For example, only in the past 30 years has it been established that too much training (overtraining) produces a specific medical condition that substantially impairs athletic performance. Similarly, until relatively recently, athletes believed it necessary to continue intensive training right up to the day of competition.
But modern athletes now know that the same high intensity training necessary to adapt the body for superior athletic performance, also produces a persisting state of mild fatigue that impairs performance during a single all-out effort. Only when there has also been a period of rest allowing full recovery from that fatigue, will a peak performance be achieved.
Similarly, modern technology has dramatically altered performance in certain sports. Two examples will suffice to make the larger point. For example, in the 1980’s, the >world record in the javelin broke the 100m barrier for the first time (Figure 1). But as the dimensions of most athletic stadia in the >world do not allow sufficient room for throws of that distance without endangering the lives of the spectators, it became necessary to alter the aerodynamics of the javelin so that only shorter throws would be possible. This effect was achieved and the newly designed javelin immediately reduced the >world javelin record by more than 15m (Figure 1). But, as is the nature of human athletic performance, the record distances have gradually increased so that the 100m barrier is again being approached.
The second example comes from the sport of cycling. Like the javelin, the bicycle and rider travel at high speeds so that aerodynamic factors become increasingly important determinants of success as the velocity of travel increases.
The modern bicycle was designed in 1888. Between that year and about 1920, there was a rapid increase in >world one hour cycling record. But from then until the mid-1980’s, the >world one-hour cycling record improved in a predictable and linear way. Then a rash of aerodynamic innovations including disk wheels, aerodynamic handlebars, aerodynamic frames, changes in the cycling position and competing in the rarefied atmosphere at altitude, produced record improvements in 5 years that exceeded the performance improvements in the previous 60 years (Bassett et al. 1999).
A more humorous example of how knowledge or conversely ignorance of technology impacts on performance, comes from the >world’s most famous cycling race, the Tour de France.
At the start of the final stage of the 1989 Tour de France, the Frenchman Lauren Fignon had an overall lead of 50 seconds. As the final stage of that race was an individual time trial in which the cyclists each race on their own without assistance from their team members, and as the race distance was only 25 km, it was not considered possible that the second rider, American Greg Le Mond, would be able to close the gap sufficiently to win the race.
In the end however, Le Mond won the race by eight seconds, the closest winning margin in the history of the race. And he won not because he had cycled better in the final stage but because he had taken the extra trouble to determine which factors open to simple modification might influence his performance.
So, unlike Fignon, he had adapted his bicycle to include a technological advance known as aerobars. This modification allows the position of the hands to be altered so that the upper body takes on the aerodynamic profile of an arrow. By comparison, the aerodynamic profile of the conventional cycling position is more like that of a shovel. This quite simple alteration can reduce one’s race time over a 40 km cycling time trial by as much as 60 seconds, or almost enough to explain by itself why Le Mond was able to snatch such a dramatic victory in the dying seconds of that race. Interestingly, aerobars were first developed and adopted by triathletes and were initially spurned by professional cyclists, perhaps on the grounds that such gimmicks were below the dignity of the true (cycling) professionals. However the performance of Le Mond immediately reversed that arrogance.
Ironically, Le Mond also received critical help from his main competitor, who chose to race the last time trial with an uncovered head and with his fashionable ponytail exposed to the wind rushing past as he raced towards the finish. Subsequent calculations showed that the ponytail cost Fignon exactly the eight seconds by which he lost the Tour de France to Greg Le Mond!
* The professionalisastion of sport
The growth of professional sport has provided athletes with the free time necessary to train as intensively as they need to optimise their performances.
It has also provided money for the purchase of scientific and medical support. This, in turn, has allowed the academic and clinical disciplines of sports medicine and sports science to evolve more rapidly.
* The use of performance-enhancing drugs
There is a perception that the use of performance-enhancing drugs is widespread throughout international sport. In part this belief is fuelled by the recent disclosures suggesting widespread drug use by athletes in the former East Germany and the events surrounding the 1998 Tour de France.
One statistic of interest is that the performance difference in track running events between men and women narrowed during the 1980’s but has since increased. In addition, very few female >world records have been set on the track in the past 12-15 years (Entine, 2000). Approximately 70% of the track records set during the 1970's and '80's, were established by athletes from the GDR and Russia.
It has been argued that the increase in the performance difference between men and women in the past decade has occurred because better methods have been introduced to control drug use by female athletes. As the athletic performance of women may be enhanced to a greater degree by the use, especially of anabolic steroids, so their performances would be more markedly effected by the introduction of stricter doping control methods in the 1990's.
* Psychological factors
One of the
great moments in >world athletics occurred on the Iffley Track, Oxford, England
on May 6th 1954 when Sir Roger Bannister became the first human to run the mile
in less than 4 minutes. Within weeks, what had previously been considered
the ultimate limit of human performance, was broken by a succession of athletes
whose previous attempts had failed. Bannister's conclusion was the following:
vein, the researchers who found that >world running records improve in regular,
linear fashion, rather than in sudden, exponential jumps, explained their findings
according to a psychological basis:
Physiological changes that explain the progressive improvements in human athletic performance.Most of the research into the physiological adaptations that result from training, and which therefore explain the progressive improvements in athletic >world records, has focused on endurance-type activities. In part this probably reflects the personal sporting inclination of the research scientists of the late 20th century, most of whom were involved in endurance sports like running, cycling, swimming and rowing. It may also result from the erroneous perception that endurance-type activities are more beneficial for health than sports involving explosive efforts like sprinting or weightlifting.
This research shows that elite endurance athletes have the following physiological characteristics:
A high capacity to utilise oxygen.
* Lung function is not a crucial factor for exercise performance at sea level but becomes increasingly important at increasing altitude. Thus lung function, in particular, the capacity to breathe continually at high rates (sustained hyperventilation) and a superior capacity to transfer oxygen across the lung membranes (lung membrane oxygen transfer) become crucial determinants of the ability to climb to extreme altitude, for example, to the summit of Mount Everest. As these factors are different from those required to be an elite endurance athlete, so it is that the >world’s best endurance athletes may not be the best qualified to climb to high altitude, a conclusion that is not immediately intuitive. Indeed,
* many of the world's greatest climbers have not been particularly athletic in terms of running ability.
* An adequate mass of red blood cells.
The illegal substance, the hormone erythropoeitin (EPO) is used by endurance athletes who wish to increase the mass of red blood cells circulating in their bloodstream. This increases artificially their ability to transport oxygen to their heart and muscles, producing a large increase in endurance capacity. Training at sea level has no such effect but living at high altitudes (>3000m) for weeks or longer may produce an equivalent effect. The International Cycling Federation has ruled that when the mass of red blood cells exceeds 50% of the total blood volume (circulating blood cells plus the fluids in which they float), the cyclist may not compete internationally. In effect, this has produced a target value, at which those cyclists who wish to use erythropoeitin, can aim.
* Muscles that have the capacity to utilize oxygen at high rates and to store and utilize energy fuels efficiently.
A large capacity of the heart to transport oxygen to the exercising muscles must be matched by an equivalent capacity of those muscles to absorb a large blood flow (requiring a large capillary network) and to extract oxygen at high rates from the blood stream. This requires an extensive network of mitochondria, where the oxygen is processed. The efficient use of energy fuels is important, especially during very prolonged exercise, when depletion of the muscles' fuel reserves, especially carbohydrate, may influence endurance performance.
* Muscles that can resist the damage due to prolonged weight-bearing.
Sports like running in which there is prolonged weight-bearing produce a specific form of fatigue during prolonged exercise in which the spring-like function of the muscles is altered. When the exercise is more prolonged, skeletal muscle damage may result.
It seems probable that the world's best endurance athletes must have muscles that are better able to resist the damage caused by prolonged, repetitive, weight-bearing activities.
* A brain that has been pre-programmed to extract the most from the athlete's body.
One theory is that fatigue during exercise is really the result of a brain that monitors a variety of bodily functions and then "switches off" the muscles when there is a risk of organ damage (Noakes, 1997; Noakes, 2000). By "switching off" the muscle contraction, the rate of heart production and energy use by the muscles is reduced. This prevents overheating (heatstroke), during high intensity exercise in the heat. The same mechanism would ensure that the heart is not damaged during high intensity exercise lasting 2-4 minutes when a maximum blood supply to the heart is required so that the risk of heart damage is the greatest (Noakes, 1998).
Promoting physical healthIf the past 32 years have seen an unprecedent growth of interest in the health and performance capabilities of international athletes, has this been matched by an equivalent rise in the promotion of sport for health? Or, stated differently, has the focus on international sporting success, especially in Olympic competition, enhanced the health of the >world’s peoples by promoting greater sporting participation around the >world? Perhaps a superficial analysis of two highly successful sporting nations, the United States of America and Australia, can give an indication of the likely answer that will be uncovered by a more detailed and rigorous scientific study.
Since the mid-1970’s, Australian success in Olympic competition, especially, has been nothing short of meteoric, rising from a total of 5 medals at the 1976 Montreal Olympic Games, to 41 at the 1996 Atlanta Games. There is a direct, linear correlation between the rise in this medal count and the amount of money spent on preparing Australian athletes for elite competition. As a result of increased support of Australian Olympic athletes, especially in 1999/2000, the prediction is that athletes from that country will win 62 medals in the 2000 Olympic Games.
However the conclusion from that country is that this major and largely unequally financial effort has not been matched by an equivalent commitment to sports participation by the Australian population.
Indeed a comparative study of children of all ethnic groups living in the 2000 Olympic City, Sydney, in either 1985 or 1998, has shown a significant increase in body mass index, a measure of obesity, for successive generations of 9-12 year old white girls and boys compared over that 13 year period (Figure 2) (Lynch et al. 2000). Hence successive generations of white Australian children have increased their levels of fatness over the 15 years in which that country has promoted elite sport.
There is also no evidence that a greater proportion of the Australian population participate in regular physical activity today than was the case in 1976 when the Australian government initiated their programme to enhance the international sporting success of Australians.
Perhaps the same applies to the citizens of the United States. Despite the commitment of the country to extensive professional sports and to success in the Olympic Games, many public health officials remain concerned that too few Americans participate in regular physical activity. The rising prevalence of obesity in that country is also considered to result, in part, from a progressive reduction in physical activity.
Perhaps the point is that a negative consequence of the greater emphasis that is placed on international sporting success, may well be increased levels of spectatorship, to sustain the financial base for those superior performances of the elite few. An emphasis on elite performance may also produce feelings of inadequacy in those who are less gifted, thereby further entrenching spectatorship.
Thus there is a real concern that seeing others with unique sporting abilities may discourage those with lesser abilities from participating in sport even at a recreational level, as has been suggested to be a developing problem in Australia and perhaps the United States, and presumably in other countries in which elite sporting performances are emphasized.
ConclusionThe 20th century saw the development of competitive sport as a global phenomenon. One beneficiary has been sports medicine and the exercise sciences, which have developed as important academic disciplines in the past 30 years. In turn, research from those disciplines has proven the value of physical activity and has further enhanced the performance of elite sportsmen and women through technological advances and as a result of a better understanding of human physiology and biochemistry.
Yet this knowledge has not been without cost. The emphasis on elite sport development has not necessarily persuaded more, especially young people, to be physically active in a meaningful way. Perhaps it has even had the opposite effect.
The challenge for the 21st century will be to develop methods that will promote physical activity for health on a global scale, just as competitive sport became a global passion in the 20th century.
ReferencesBannister, R.G. Muscular effort. British Medical Bulletin 12: 222-225, 1956.
Bassett, D.R., Kyle, C.R., Passfield, L., Broker, J.P., Burke, E.R. Comparing cycling >world hour records, 1967-1996: modelling with empirical data. Medicine and Science in Sports and Exercise 31: 1665-1676, 1999.
Entine, J. Why black athletes dominate sport and why we're afraid to talk about it. Public Affairs, New York, 2000, pp. 1-387.
Lynch, J., Wang, X.L., Wilcken, D.E. Body mass index in Australian children: recent changes and relevance of ethnicity. Archives of Diseases in Children 82(1): 16-20, 2000.
Noakes, T.D. Challenging beliefs: ex Africa semper aliquid novi. Medicine and Science in Sports and Exercise 29(5): 571-590, 1997.
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Table 1: 15 Laws of Training1. Train frequently all year round.
2. Start gradually and train gently.
3. Train first for distance, only later for speed.
4. Don't set yourself a daily schedule.
5. Alternate hard and easy training.
6. At first, try to achieve as much as possible on a minimum of training.
7. Don't race in training, and run time-trials and races longer than 16 km only infrequently.
9. Incorporate base training and peaking (sharpening).
10. Don't overtrain.
11. Train under a coach.
12. Train the mind.
13. Rest before a big race.
14. Keep a detailed logbook.
15. Understand the holism of training.
Legend to Figure 1.Progressive >world record performances in the men's javelin. Note that when the record exceeded 100m it was necessary to introduce a less aerodynamic javelin in order to spare the lives of the spectators. As a result, the distances of the javelin >world records fell.
Legend to Figure 2.Changes in body mass index, a measure of obesity, in successive generations of 9-12 year old white boys and girls living in Sydney, Australia, host of the 2000 Olympic Games. Note that the body mass index of white children, but not those of other ethnic groups, has increased in the 13 years between the measurements that were taken (1985-1998).
from Lynch et al. (2000).