Which lap is the slowest? An analysis of 32 world mile record performances
- 1 UCT/MRC Research Unit for Exercise Science and Sports Medicine, Department of Human Biology, University of Cape Town, Cape Town, South Africa
- 2 Association of Track and Field Statisticians, Parow, South Africa
- 3 Association of Road Running Statisticians, Parow, South Africa
- Correspondence to Dr Timothy D Noakes, UCT/MRC Research Unit for Exercise Science and Sports Medicine, Department of Human Biology, Boundary Road, Newlands, 7700, South Africa;
- Accepted 19 February 2008
- Published Online First 18 April 2008
Objectives: The pacing strategies adopted by world-record breakers during the 1-mile footrace in order to evaluate different models for the biological basis of pacing was determined in this study.
Methods: Lap times in 32 world record performances were analysed. Average times for each of the four laps and as percentages of total race time were calculated.
Results: The slowest laps in 90% of races were either the second (34%) or the third (56%) laps. In only two (6%) records was the final lap the slowest, whereas in 24 (76%), it was either the fastest (38%) or the second fastest (38%) lap. Mean times for the second and third laps were both significantly slower than were times for the first or final laps, but there was no significant difference in times for the first and final lap.
Conclusion: The finding that world record beaters run the final lap in their quickest mile races faster than the second and third laps matches findings for races at longer distances. The presence of this “end spurt” suggests that the pacing strategy is regulated “in anticipation” and is not purely the result of a developing “peripheral fatigue”.
Fifty-four years ago, on 6 May 1954, the English medical student (now Sir) Roger Bannister became the first human to run the mile in less than 4 min.1 2 3 An important component of Bannister’s strategy during the famous race on the Iffley Road (Oxford) track was the use of two athletes, Chris Chataway and the late Chris Brasher, to pace him during the first three and a third laps of the race. This allowed Bannister to spare his effort for an “endspurt” during the final 300 m of the race.2 Later, he concluded that this pacing strategy probably explained why he, and not the Australian, John Landy, or the Kansan, Wes Santee, was the first to breach that iconic barrier.2 3 Bannister’s strategy evolved from his deduction that the two Swedish runners, Gunder Hägg and Arne Andersson, had successfully lowered the world mile record by 5 s between 1942 and 1945 (table 1) because they had always raced and hence paced each other, thereby unwittingly proving the crucial value of pacing.
An analysis of Bannister’s pacing strategy in his successful world record on 6 May 1954 shows that his fastest laps were the first and fourth (fig 1) with laps 2 and 3 being progressively slower than lap 1. Furthermore, the advantage of running behind a pacer, as did Bannister for the first three and a third laps of the first sub-4 min mile,1 is now known to be approximately 1 s per 400 m lap.4 Thus, had Bannister also run behind a pacer in his final lap, for the same effort, his final lap would have been 1 s faster, and hence his fastest.
Interestingly the biological basis for such a performance is not immediately clear according to a currently popular theory,5 6 7 8 9 10 11 12 13 14 15 16 which holds that the running pace during high-intensity exercise at ∼100% Vo2max is limited by a progressive accumulation of metabolites, especially lactate and protons or the depletion of high energy phosphates. It is usually argued that either individually or together, these changes progressively impair skeletal muscle contractile function leading ultimately to exhaustion. Since it is generally accepted that maximum exercise lasting ∼4 min is performed at ∼100% Vo2max,6 this model must predict that unless athletes choose to run at a lower exercise intensity for some laps—that is, to pace themselves—each successive15 16 lap will become progressively slower as these skeletal muscle biochemical derangements become increasingly more severe. The one pattern excluded by this model is the very one achieved by Sir Roger Bannister on 4 May 1954, in which he increased his pace in the last quarter of the race (fig 1).
Accordingly, to determine whether Bannister’s pacing strategy was unique allowing him to speed up when he should have been the most fatigued and hence should have been slowing in the final lap of the race, we analysed the pacing strategies of all 1-mile world records for which the data are available. Specifically, we wished to determine the usual pacing strategy adopted by all these world mile record breakers to establish whether, as is the case in races at longer distances,17 athletes retain the capacity to increase their pace and to finish with an “end spurt”.18 The presence of an end spurt is compatible with an exercise model in which the pace is regulated “in anticipation” by a complex, intelligent system13 14 15 16 19 20 21 22 23 but cannot be explained by the traditional “peripheral fatigue” model.5 8 9
An analysis of variance with repeated measures and a Tukey’s HSD post hoc test was used to determine differences in lap times. Statistical significance was accepted as p<0.05. Values are expressed as mean (SD).
Table 1 lists the 32 performances that were analysed. Lap times have been rounded to the nearest tenth of a second, and this explains some discrepancies between mile time and the sum of the four individual lap times.
In a majority (56%) of performances, the third lap was the slowest, whereas in another 34%, the second lap was the slowest (table 1). Thus in 90% of races, either the second or the third laps was the slowest. As a result, times in the second and third laps were significantly (p<0.05) slower than those in either the first or final laps (fig 2A). Similarly, the percentage of total race time spent running the second and third laps was also significantly (p<0.05) greater than for the first and final laps (fig 2B).
In only two world record performances (Arne Anderson, 10 July 1942; John Landy, 21 June 1954) was the last lap the slowest (table 1). Indeed, this was the usual pacing strategy for John Landy.2 In 12 (38%) record performances, the last lap was the fastest, and in another 12 (38%), the final lap was the second fastest.
This study of 32 world record performances in the mile shows that in only two (6%) races was the final lap the slowest. In contrast, the final lap was the fastest in 12 (38%) record performances, and in a further 12 (38%), it was the second fastest in the race. Thus, in 76% of races, the final lap was either the fastest or the second fastest lap in the event. Indeed, both the first and final laps were run significantly faster than the second and third laps (fig 2).
This is especially surprising since, by definition, the world record holder must have led for at least a part of the final lap. As leader, he would have been exposed to an increased aerodynamic drag sufficient to slow his speed by at least 1 s for each 400 m that he led.4 Thus, the effort expended by the record breaker would be less at any running speed in laps 1–3, if he chose to run behind the leader(s) than during that part of the final lap in which he was forced to lead the race. However, the extent to which the record breakers chose to run behind pacers in laps 1–3 is speculative, since we did not review the race footage to determine when the record breakers first took the race lead. However, it is extremely uncommon for a record breaker to run very much at the front before the final lap.
Thus, the significantly slower lap times in laps two and three compared to the final lap (figs 1 and 2) hide the additional beneficial effect of running in an aerodynamic shadow during those laps and which benefit is lost by the race winner sometime during the final lap. The implication is that, with the exception of those athletes who were paced for more than three laps, had all the other record breakers been paced for all but the last few metres of the race, then the final lap times would have been even faster than the values reported in table 1. In which case, an even larger proportion of the final laps would have been the fastest in the race.
This finding that the average time in the final lap was significantly faster than the times for laps two and three, but was not significantly slower than the first lap, matches our finding in races of longer distances17 in which athletes speed up near the end of the race, exhibiting an “end spurt”. The presence of an end spurt indicates that the pacing strategy during exercise is regulated “in anticipation”20 22 23 and conflicts with the explanation that it is the result of a peripheral fatigue caused by a failure of homeostasis in the exercising limbs.5 8 9 10 11 27 28 Were this the case, running speeds in all high-intensity events performed at intensities above the so-called “anaerobic threshold” and in which blood lactate concentrations rise progressively,28 would initially be very fast, falling exponentially as the concentrations of these metabolites continue to increase.
As reviewed previously in detail in this journal,14 the origins of this model can be traced13 14 15 16 19 29 to the work of Fletcher and Hopkins30 and A V Hill.10 11 Hill10 believed that lactic acid produced by anaerobic conditions in the exercising muscles served two opposing functions. Its initial production stimulated muscle contraction; in the presence of an adequate oxygen supply, the oxidative removal of lactic acid produced the “neutralisation” necessary to allow muscle relaxation. However, at the higher exercise intensities at which they believed skeletal muscle anaerobiosis developed, lactic acid could no longer be neutralised but accumulated progressively leading ultimately to a progressive failure of skeletal muscle relaxation. Hill believed that this effect was clearly visible in competitive sport: “This effect is very striking in short distance races, where slower muscle relaxation, commencing within seven or eight second from the start, causes a progressive diminution in the maximum speed long before exhaustion. The formation of lactic acid is the chemical reaction on which the whole of voluntary activity depends”.10
This interpretation has become part of the folk lore of exercise physiology. Thus, it has been written that: “Your marathon pace is very close to your lactate threshold pace, which is determined by your oxygen consumption at your lactate threshold and your running economy. If you run faster than your lactate threshold pace, then lactate accumulates in your muscles and blood; this occurrence deactivates the enzymes for energy production and makes you slow down”.12 Polar explorer and medical biologist Michael Stroud31 has written that: “But if high levels of work are sustained for more than a few seconds, the lactic acid formed from this process begins to accumulate. This poisons several enzymes systems, including the one splitting glucose from glycogen. Within a 100-metre race, such lactic acid effects hardly matter, but go for more than 200 metres and even top class sprinters begin to falter. It is lactic acid build-up that explains why world records for 100 metres are well under ten seconds, for 200 metres are less than twenty, but for 400 metres are around 43 seconds and for 800 metres close to 100 seconds” (p 42)31 and “When most of us run hard, even for a few seconds, we rapidly feel our legs turning to jelly as the lactic acid builds up” (p 43).31 Or as Aschroft32 has written: “Anaerobic metabolism cannot continue forever, however, because it produces lactic acid, and the accumulating lactic acid eventually impedes muscle activity and causes fatigue. Lactic acid accumulation is also painful and is responsible for the “burn” often referred to by trainers—to ‘go for the burn’ means to exercise to the limits of your anaerobic capacity”.
All these ideas mirror the original statement of Webster28 in 1948 that: “First, the sprinter very quickly creates what is termed an ‘oxygen debt’; and secondly, the valuable glycogen inside the muscle fibres is turned into poisonous lactic acid, the muscles become tired and stiff, dwindle in power, and finally refuse to function until the lactic acid has been turned back to glycogen during the recuperative processes of rest”.28 (p.75)
The one pacing strategy that this model does not allow is one in which the speed increases near the end of exercise—the “endspurt”18 that is present in races of 5000 m or longer17 and which we now confirm also occurs in the mile race (fig 2).
In summary, these data show that the majority of world record holders in the mile adopt a pacing strategy in which they run the slowest in the second and third laps even though they are likely to be running in the aerodynamic shadow of other racers during those laps. As a result, their absolute effort during that middle section of the race will be less than when they run by themselves at the same or even a slightly faster pace in the final lap. This finding is not compatible with a popular model of exercise physiology,13 which holds that the pacing strategy is limited by the development of a progressive peripheral fatigue, which will cause the pace to fall with each successive lap. Rather the data are more easily explained by a model in which alterations in running speed during the mile are produced principally but not exclusively by alterations in the number of motor units recruited centrally by the brain, the so-called Central Governor Model,14 and not by any “poisonous” effects of lactate on skeletal muscle function.15 16 17 22 23 33 34 35 36 37 38 39 It has also been shown repeatedly that lower limb electromyographic (EMG) activity, an indirect measure of the extent of skeletal muscle activation, increases during the end spurt23 40 41 42 in line with the prediction of this model.
This interpretation is also compatible with the more usual teaching in physiology that changes in muscle force production (and hence in running speed) are produced principally by changes in the number of skeletal muscle motor units that are recruited during exercise43 44 and the finding that there is always motor unit reserve during exercise.14 15 16 29 42 45 46 47 48 49 50
What is already known on this topic
A popular theory holds that noxious biochemical changes in the exercising muscles causes the development of “peripheral fatigue” in the active muscles ultimately “limiting” human exercise performance. This model also predicts that this “peripheral fatigue” must become progressively more severe as exercise progresses. We have previously shown that this model cannot explain the performances of world-record beaters in 5000 and 10 000 m running races, since these athletes increase their pace near the end of the race, achieving their fastest running speeds in the final 10% to 20% of these races—the “end spurt”. Whether the same phenomenon applies in the 1 mile running race has not been established.
What this study adds
This analysis of the pacing strategies adopted by 32 world record beaters in the 1-mile running race found that the final lap was the slowest in only 6% of records, whereas in 76%, it was either the fastest (38%) or the second fastest (38%) lap. The second and third laps were both significantly slower than were the first or final laps, the paces of which were not significantly different. Changes in pace during the 1-mile running race, including the presence of the “end spurt” shows that the pacing strategy is regulated “in anticipation” and is not purely the result of a developing “peripheral fatigue”.
The research undertaken in the Unit is funded by the Harry Crossley and Nellie Atkinson Staff Research Funds of the University of Cape Town, the Medical Research Council of South Africa, Discovery Health and the National Research Foundation of South Africa through the THRIP initiative.