Aerobic Energy Contribution to Short and Middle Distance Running

Previously we’ve compiled evidence that high-intensity athletic efforts are significantly more aerobic than once thought. Such evidence reveals that high-intensity efforts as short as six seconds can become significantly aerobic, and single max. efforts lasting less than one minute can be predominantly aerobic (i.e. more than 50% of the ATP is supplied by the aerobic system). While the evidence demonstrates a significant, progressive shift towards greater aerobic contribution during interval repeats, it also reveals the crossover from dominant anaerobic to dominant aerobic energy production can occur within the first 30 seconds of intense activity (correcting the old misconception that aerobic energy dominance requires several minutes or more and/or sub-maximal intensity). Together, this body of evidence suggests that short-duration, high-intensity training can deliver tremendous aerobic and endurance benefits because the training itself can be highly aerobic.

Adding to the evidence, we highlight below two separate studies that evaluated energy system contribution to maximal effort running of various short and middle distances. Two separate research groups conducted these studies independently and arrived at remarkably similar results.

Spencer and Gastin (2001)

In 2001, Matt Spencer and Paul Gastin analyzed energy system contribution to single, maximal-effort 200, 400, 800, and 1500 meter runs (See “Energy System Contribution During 200- to 1500-m Running in Highly Trained Athletes” (PDF)). They used 20 highly trained males, all of whom had competed at state, national, and/or international competition, each of whom were specialists in one of the distances to be tested. Each specialist was tested in their specialty distance only. The tests were conducted on a treadmill, set at 1% gradient to simulate the supposed energy cost of outdoor running. Energy system contribution was determined by measuring expired gases from the breath of the tested subjects while they ran.

The results showed the relative total contribution of the energy systems as follows:

Graphed by distance, the aerobic/anaerobic contribution looks like this:

As expected, the shortest distance/duration event (200 m.) required the lowest relative aerobic contribution while the longest distance/duration event (1500 m.) required the greatest relative aerobic contribution. While this finding isn’t new, the extent and timing of aerobic contribution is remarkable since it occurs earlier and in higher percentages than commonly understood. For instance , the aerobic system appears to contribute nearly one-third of the total energy required in a 22-second 200 m. run and nearly half of the energy required in a 49-second 400 m. run. Based on the current study, the anaerobic and aerobic energy systems appear to contribute equally to single, max. effort runs at distances just beyond 400 m., somewhere between 50-75 seconds. Remember, this does not account for less-than-maximal efforts (where the aerobic contribution would be greater sooner) or repeated runs such as those used during interval training sessions (where the aerobic contribution would progressively increase and occur progressively sooner even in the shortest distances/durations). It also doesn’t account for the mid-run crossover to aerobic dominance which we’ll discuss below.

In support of their findings, Spencer and Gastin reference comparable studies with similar findings. For instance, regarding the current finding of 29% mean aerobic contribution to the 22-second 200 m. trials, Spencer and Gastin found this was similar to the finding of 28-40% mean aerobic contribution during 30 seconds of exhaustive cycling measured by Medbo and Tabata (1989), Withers et. al. (1991), and Medbo et. al. (1999). Spencer and Gastin’s finding of  43% mean aerobic contribution to 49-second, 400 m trials was similar to findings of 37-50% aerobic contribution in 49-57 seconds of exhaustive treadmill running measured by Medbo and Sejerssted (1995) and Nummela and Rusko (1995), and to 40% aerobic contribution to 45 seconds of maximal cycling found by  Withers et. al (1991). Spencer and Gastin’s 800 meter findings, with 66% mean aerobic contribution in 113 seconds, compared favorably to Craig and Morgan (1998) and Hill (1999) and Spencer et. al. (1996) who reported 58–69% aerobic contribution during 116 –120 seconds of running. Lastly, Spencer and Gastin’s data regarding the 1,500 appeared similar to findings of Spencer et. al. (1996) and Hill (1999) who reported 75– 83% aerobic contribution for subelite 1500-m runners.

Crossover to Aerobic Dominance

During most exercise, there comes a time when energy supply from the aerobic system begins to exceed energy supply from the anaerobic system. This is known as the “crossover” point to aerobic dominance. We have explained in prior posts that this crossover is now thought to occur much earlier during exercise than previously understood (folks wrongly used to think it took several minutes or more). The Spencer and Gastin study supports this revised view as revealed by the following figure:


As seen in the figure, the actual crossover to aerobic dominance occurred between 15 and 30 seconds during the 400, 800, and 1500. In other words, within 30 seconds or less of maximal effort, the aerobic system became responsible for providing more energy than the anaerobic system. It may be important to note that this crossover to aerobic dominance occurs even in short events like the 400 m where a portion of the effort becomes dominantly aerobic despite the overall greater anaerobic contribution. This helps explain why poor aerobic conditioning can cause poor 400 m. performance and, likewise, why 400 m. repeats (or shorter) can have significant aerobic/endurance benefits. Again, it may also be useful to keep in mind that the aerobic crossover point in any distance, no matter how short, will occur progressively sooner and increase progressively faster when intervals are repeated and/or intensity declines.

Spencer and Gastin conclude:

[T]he relative contribution of the aerobic energy system is considerable and greater than has been traditionally accepted during 200-, 400-, 800-, and 1500-m running. The results demonstrate that the aerobic energy system is the predominant energy system by the 30-s time period during the 400-, 800-, and 1500-m running events.

Duffield and Dawson (2003)

In 2003, Rob Duffield and Brian Dawson evaluated the energy system contribution to single, maximal-effort 100, 200, 400, 800, 1500, and 3000 meter runs (See “Energy System Contribution in Track Running” (PDF)). Not content to rely on simulated race performances on a treadmill or mere data modeling, they conducted live tests on a 400 meter track. They used 66 trained track athletes (male and female) with experience ranging from club to national level. Each of the runners had a specialty distance and was tested only in that specialty distance. Energy system contribution was determined by measuring expired gases from the breath of the tested subjects while they ran (using a portable device by Cosmed) and by measuring blood lactate before and after the runs.

The results showed the relative total contribution of the energy systems as follows:

Graphed by distance, the aerobic/anaerobic contribution looks like this (note: we averaged the male and female #s):

Again, not surprisingly, Duffield and Dawson found that relative total aerobic contribution increased as event distance and duration increased. Relative aerobic contribution was the lowest in the 100 m run and greatest in the 3,000 m run. Similar to Spencer and Gastin, Duffield and Dawson found that the total energy production was approximately equal at a distance just over 400 m, or approximately 50 seconds of maximal effort. Also similar to Spencer and Gastin, Duffield and Dawson found that the crossover point to aerobic dominance occurred well before the one minute mark:

[D]uring the 1500m and 3000m events, the aerobic and anaerobic energy systems show a cross over in dominance between the respective systems by 200m (~30 sec). During the faster sprint endurance events, a cross over point occurs between the 200- and 400m mark (~40 – 55 sec)

Though the Duffield and Dawson crossover points appeared to occur slightly later than those measured in Spencer and Gastin, both groups confirm that this crossover occurs well-within the first minute of intense activity. Also, it makes sense that the crossover to aerobic dominance would occur sooner in the longer distances since presumably the longer distance runners began their runs at slightly lower relative intensities than the sprinters. At lower relative intensities, the aerobic crossover point is bound to occur earlier. Finally, at the risk of belaboring this point, repeating these max. efforts as intervals and/or any further reductions in intensity would elicit a crossover to aerobic dominance far sooner and at a greater rate.

Dawson and Duffield conclude by stating humbly:

[T]hese studies highlight and confirm previous research outlining both the significance of and speed at which the aerobic energy system becomes involved in maximal exercise between 11 sec and 10 min.

Taken together, we think the Spencer and Gastin study along with the Duffield and Dawson study lend great explanatory power to lower-volume, higher-intensity training protocols for endurance athletes. Whereas short, hard efforts were once considered predominantly anaerobic and therefore unsuitable for the aerobic training needs of serious endurance athletes, we are learning that this view is mistaken. Instead, short-hard efforts (whether or not repeated, but especially when repeated) call upon the aerobic system, not the anaerobic system, as the primary source of energy. Because they engage the aerobic system directly, early, and predominantly, such efforts lead to significant aerobic adaptations and thus improve endurance.

We’ve added both of these studies to our Research Library as:

  • Spencer, MR and Gastin, PB, Energy system contribution during 200- to 1500-m running in highly trained athletes, Med Sci Sports Exerc. 2001 Jan;33(1):157-62. [Abstract] [Full PDF]
  • Duffield, RJ and Dawson, B, Energy system contribution in track running, New Studies in Athletics,18:4; 47-56, 2003. [Full PDF]

Note: It appears the Duffield and Dawson study was later republished as a series of separate papers, each covering two of the six distances studied:

  • Duffield, RJ and Dawson, B, Energy system contribution to 100-m and 200-m track running events, J Sci Med Sport. 2004 Sep;7(3):302-13. [Abstract]
  • Duffield, RJ and Dawson, B, Energy system contribution to 400-metre and 800-metre track running, J Sports Sci. 2005 Mar;23(3):299-307. [Abstract]
  • Duffield, RJ and Dawson, B, Energy system contribution to 1500- and 3000-metre track running. J Sports Sci. 2005 Oct;23(10):993-1002. [Abstract]

We have also added to our Research Library the following comparable studies cited by Spencer and Gastin and mentioned in our summary above:

  • Craig I.S. and Morgan, D.G. Relationship between 800-m running performance and accumulated oxygen deficit in middle-distance runners. Med. Sci. Sports Exerc. 30):1631–1636,1998. [Abstract]
  • Hill, D. W., Energy system contribution in middle-distance running events, J. Sports Sci. 17:477– 483, 1999. [Abstract]
  • Medbo, J., Gramvik, P., and Jebens, E., Aerobic and anaerobic energy release during 10 and 30 s bicycle sprints. Acta Kinesiol. Univ. Tartuensis 4:122–146, 1999.
  • Medbo, J., and Sejersted, O., Acid-base and electrolyte balance after exhausting exercise in endurance-trained and sprint-trained subjects. Acta Physiol. Scand. 125:97–109, 1985. [Abstract]
  • Medbo, J., and I. Tabata. Relative importance of aerobic and anaerobic energy release during short-lasting exhausting bicycle exercise. J. Appl. Physiol. 67:1881–1886, 1989. [Abstract]
  • Nummela, A., and Rusko, H., Time course of anaerobic and aerobic energy expenditure during short term exhaustive running in athletes. Int. J. Sports Med. 16:522–527, 199. [Abstract]
  • Spencer, M.R., Gastin, P.B., and Payne, W.R., Energy system contribution during 400 to 1500 meters running. New Studies Athl.11(4):59 – 65, 1996.
  • Withers, RT, Sherman, WM, Clarket, DG, et. al., Muscle metabolism during 30, 60, and 90 s of maximal cycling on an air-braked ergometer. Eur. J. Appl. Physiol. 63:354 –362, 1991. [Abstract]




  1. Mike Keeler says:

    It just seems to me that you are taking alook at this from a completely backwards view. Just because short duration work has a significant aerobic component doesn’t mean that you can improve aerobic capacities by using exclusive short duration work. In fact, it seems to state the exact opposite. You need to do aerobic work to be good at short duration events. In other words, there is a big difference btwn an aerobic contribution during short work and the development of the aerobic system. Interesting topic and I appreciate the work you are putting into posting the studies.

    • Neil says:

      Mike thanks for your comment. We agree in a sense – knowing the energy system contribution to an event by itself doesn’t tell us much about the effectiveness of an endurance training protocol. We’ve given the wrong impression if that’s how it seems we’re using it here.

      Instead, as far as we can tell, the science is already very clear that repeated short-duration, high-intensity efforts can significantly improve the aerobic system, other endurance qualities, and endurance performance. The Tabata study* and countless other studies confirm this. Not to mention there are growing throngs of athletes who train this way exclusively. Sure there’s room for reasonable debate over the details (e.g. What are the pros/cons of training this way? What are the limits? etc.) but the basic concept is no longer very controversial.

      So the questions turn towards “why?” and “how?” If such protocols can be effective, what makes them so? And that’s where we think the potential explanatory power of energy systems analysis fits.

      *though the study is widely misinterpreted and misapplied, the Tabata study explicitly states “…the intermittent training increased·VO2max significantly in experiment 2. This is to our knowledge the first study to demonstrate an increase in both anaerobic capacity and maximal aerobic power…High-intensity intermittent training is a very potent means of increasing maximal oxygen uptake. “

  2. Robbie-O says:

    HIIT makes sense from a simplified view of training, similarly expressed by Brooks: It is directly overloading the aerobic system because the energy demand exceeds the ability to continue to supply ATP, thus the body adapts by increasing aerobic capacity. That being said, adaptations like LV eccentric hypertrophy seem to optimally occur between HR of 120-150, and generally HIIT Hr’s are far beyond that. I think LSD has a very secure place in building the pumping capacity of the heart, but after those adaptations occur, not much need to continue to go for so long. Further, HIIT seems to be effective on a shorter term basis (i.e. 4-6 weeks), versus longer distance, lower intensity training which can continue to provide training stimulus for quite a while.
    I feel like intervals are like a shot, and LSD is like beer. Get the right mix and you’ll have a great time.

    • Neil says:

      Thanks Robbie. If the benefits of high-intensity and strength training for endurance athletes ceased after 6 weeks, nobody would use them exclusively for long-term training. Yet a growing number of people have used them exclusively for years and keep improving. How do you account for this? True, some people like a mix. But we are aware of no evidence that LSD is necessary nor that intensity-based training benefits end in mere weeks.

      P.S. Which Brooks are you referring to?

  3. Robbie-O says:

    George A. I should have clarified that I meant a particular protocol, like 30 seconds on 4 min rest, only seem to show benefits for a shorter term duration, not HIIT in general. So like all training, rotating methods as adaptation occurs is required. Also, necessary doesn’t mean optimal, many have used LSD as means of recovery while still building volume to further their athletic endeavors. That being said, with a solid cardiac output base, I would much rather go for 15 minutes than 1.5 hours of training. Fantastic blog, hope to have more great discussions on here.

    • Neil says:

      Thanks for the clarification Robbie. And for the kind words. We’re with you re: the need for variety/novelty.

      Did you have a specific Brooks paper in mind that deals explicitly with direct aerobic overload from HIIT and resulting adaptive increase in aerobic capacity?

      • Robbie-O says:

        It is in his Exercise Phys. text, I’ll see if I can dig it up. I forget the addition, somewhere around 2002, so very possibly it has been rephrased in a newer edition, or omitted. It has always struck me as a very succinct explanation of training and the good-old principles of overload and progression.

        • Neil says:

          Thanks! If you find it, we would be very interested. Your initial reference to it resembled something we wrote a bit ago:

          Here’s our preliminary theory: Virtually all high-intensity (interval) training shifts quickly towards aerobic dominance. The will to keep going fast combined with the anaerobic systems’ inability to make it so places brutal, concentrated loads directly on the aerobic system. These brutal, concentrated loads force direct aerobic adaptations, namely the ability to produce ATP aerobically at higher and higher rates (remember the example of the rattlesnake?). As the demand for aerobic ATP increases with continued high-intensity interval repeats and the will to keep going faster, so the aerobic system is forced to increase its ATP production capacity. By enhancing aerobic ATP production capacity in this way, endurance performance may improve significantly. This appears to be a direct consequence of the intense aerobic stimulus of high-intensity training. It also means the parlance of aerobic vs. anaerobic training may require revision to remain meaningful.

          Meantime, we just ordered Brooks’ book on Bioenergetics. Thanks for the tip!

  4. Brad Gutting says:

    Not a single endurance sport coach alive believes that you can achieve top performance without considerable high-intensity training. Ask any cyclist who wins races: they do workouts that dwarf many tough CrossFit WODs in terms of brutality and intensity, and they don’t just do them “occasionally.” It’s a crucial part of anyone’s training. Runners put tons of effort into their interval work, too. Read Jan Olbrecht’s Science of Winning for insight into how hard swimmers have to train. Nobody who wants to do as well as they possibly can has ever forsaken intensity.

    Think about this in terms of necessity and sufficiency. Long, slow training is not sufficient for optimum endurance performance, but it is necessary. High intensity intervals are necessary for optimum performance, but they alone are not sufficient. The two modalities together are necessary and sufficient.

    Robbie-O pointed out quite rightly that LV hypertrophy is best stimulated by long sessions at HR120-150, but working in that zone leads to benefits beyond just that. At the very least, it develops greater capillary and mitochondria density, which is necessary for improving performance in any event that at all relies on aerobic metabolism. The higher your aerobic capacity is, the higher your anaerobic capacity can be; but it’s the balance of the strength of each system that’s so critical for events of varying durations. Remember, the aerobic system can metabolize fats and carbohydrates for energy. If your anaerobic system is too weak, it won’t produce enough lactate (carbohydrate) and you’ll have to rely on metabolism of free fatty acids for energy–a slower process, which leads to weaker muscle contractions, and thus slower speeds. A strong-enough anaerobic system produces the right amount of lactate for the aerobic system to burn, just as a too-strong anaerobic system will overwhelm the body, reducing muscle tension and contraction strength (be it an excess of hydrogen ions or a depolarization of the muscles through the release of potassium), and thus slowing you down.

    Is the idea to figure out what is true, or to prove that intervals can somehow replace distance work? A cursory look at the training histories of athletes who can run a sub-15 5K or a sub-30 10K, or a 2:30 marathon show that all of them have, at some point, and for a not-insignificant duration, done huge amounts of longer, slower training. The same applies to rowers, skiers, swimmers, and cyclists. Do you really think that Tour de France riders want to ride 20,000 miles a year, just to have a chance at qualifying? Of course not. But that’s the reality. They can’t Tabata themselves to a 400 watt prologue TT. They can’t ride at the +5watt/kg bodyweight power output necessary to finish with the pack on L’Alp de Huez on intervals alone.

    This study sheds some light on the issues at hand:

    This essay has some good sources that are worth investigating:

    Of course, you can react to these as you please. You don’t have to believe them, but it makes little sense to dismiss them. I mention it only because I sought high-levels of performance through doing lots of high-intensity work. It alone was–you guessed it–not sufficient. As a rower, I stagnated in the 6:50′s on my 2K just off of HIT. Longer and slower (really slow) sessions drove that time down to 6:32. And because of that training, I could access a level of pain in my interval work heretofore unseen. It took BOTH to get there.

    I realize that most people who enter a 5K or 10K race, or sign up for a challenging triathlon aren’t chasing elite performance and they’re not dying to make the podium or even top their age group. But that doesn’t by extension mean that you can replace duration with intensity. It doesn’t work that way.

    • Neil says:

      Brad, thanks for your comment. We don’t deny there are benefits associated with long, slow training. But many people use it exclusively. And a growing number of people don’t use it at all.

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