Same Engine, Different Miler
VO2max sets the ceiling. Economy and the finish decide who uses it.
A fast mile is three things multiplied together: the size of the aerobic engine (VO2max), how efficiently you turn that oxygen into speed (running economy), and how much of that ceiling you can hold for about four minutes. Push all three up and you run faster. The catch for a coach is that they don't respond to the same training, and the mile needs one thing the marathon doesn't, a real anaerobic contribution and the leg speed to spend it.
Most of what separates milers is aerobic, and the numbers are blunt about it. When Ingham's group modelled 62 national and international 800m and 1500m runners, VO2max and running economy were the variables that mattered, and a composite of the two accounted for about 96% of the differences in performance. The engine and the efficiency carry the event. The rest decides the close ones.
The engine sets the ceiling, economy decides who uses it
VO2max is the most oxygen you can take in and use, the ceiling on aerobic power. It's necessary and it isn't enough, because two runners with the same VO2max can be a long way apart once you watch them run. The difference is economy, how much oxygen it costs each of them to hold a given speed.
Figure 01 / Interactive
Same engine, three economies
Running economy / tap to change
Same 70 ml/kg/min engine, an efficient stride. That efficiency turns the engine into the fastest usable speed, and it's the runner most likely to still be there at the bell.
Economy did this, not a bigger VO2max.
Average economy at the same VO2max costs roughly 2 km/h of usable speed. Over a mile that's the gap between contending and hanging on.
Identical engine. Different transmission.
Same engine, costly economy, nearly 4 km/h slower at VO2max than the efficient runner. The engine isn't the problem here, the way they spend it is.
This is the runner strength and plyometric work helps most.
Arithmetic, not a study result. Speed at VO2max equals VO2max divided by the oxygen cost of running. VO2max is held at 70 ml/kg/min; the three economy values (roughly 190, 210 and 230 ml/kg/km) sit inside the trained range collated by Barnes and Kilding (2015). Real economy is individual, so read these as the size of the effect, not as targets.
The gap is not small. Hold the engine fixed and swing economy across the range you'd see in trained runners, and the usable speed at VO2max moves by several km/h. Economy is a trait built from metabolic, cardiorespiratory, biomechanical and neuromuscular factors, and the useful part for a coach is that it responds to work that isn't only running. Heavy resistance and plyometric training improve economy, time-trial performance and sprint speed in distance runners, and leave VO2max and body composition unchanged.
None of that lifts VO2max. The engine stays the same size, the runner just spends less to move it, which is how two athletes with matched lab numbers can finish a straight apart.
The third lever, how long you hold the ceiling
VO2max and economy set the fastest speed you can reach. The third determinant is how much of that you can hold for four minutes. A mile is run at or above the speed at VO2max, so the runner isn't sitting at a comfortable fraction the way a marathoner does. What matters is how high a share of the ceiling you sustain before the anaerobic cost climbs, and how fast your oxygen uptake rises in the first minute, so you're not running deep in debt while the engine catches up.
This is the quality threshold work builds. Push up the speed you can hold just under the point where lactate rises steeply, and you reach the bell with less accumulated cost and more left for the part that decides places. It's also the lever most sensitive to the shape of the training week, which is where 800m and 1500m runners start to separate.
The number that folds them together
Rather than track VO2max and economy separately, it's often cleaner to use the speed at VO2max, or vVO2max, which is just VO2max divided by the oxygen cost of running. It rolls the engine and the efficiency into one running speed, and it sits very close to middle-distance performance: 1500m race speed predicts vVO2max almost perfectly, with a correlation around 0.90. That makes it a good training target, specific and trainable, and it climbs whenever either the engine or the economy improves.
The slice that decides finishes
For all that aerobic dominance, the mile isn't the marathon. It blends the demands of distance running, high VO2max, good economy, a high threshold, with a genuine need for speed and anaerobic power.
Figure 02 / Interactive
Where the energy comes from, and how it shifts
Race distance / tap to change
Run over roughly four minutes, the mile is fed almost entirely by the aerobic system. The anaerobic slice is small, and it's the part that covers a surge at 1200m and the sprint off the last bend.
Drop to the 800m and about a third of the race is anaerobic, three times the mile's share. That's why 800m runners train more speed and power, and why a strong miler isn't automatically a strong 800m runner or the reverse.
Aerobic and anaerobic share of total energy. The 800m share (about 66% aerobic) is reported by Sandford et al. (2019), as is the 1500m value (about 88%) the mile is estimated from. The mile runs a little longer than the 1500m, so it's shown here at about 89%, an approximation rather than a separate measurement.
Over roughly four minutes the mile is about 88 to 89% aerobic, so the engine runs the race. That last tenth, though, is where finishes are won, and it needs leg speed the aerobic work won't build. It's also why 800m and 1500m runners train apart: 1500m runners spend about 90% of their running sessions below anaerobic threshold against roughly 60% for 800m runners, and 800m runners do more strength, power and plyometric work. A big aerobic engine makes you a candidate for the mile. It doesn't hand you the finish.
Why 800 and 1500 runners train apart
The two events share a large aerobic base, then split on how the hard work is spread and how much power the athlete builds off the track.
Figure 03 / Interactive
Two events, two training shapes
Event / tap to change
About nine in ten running sessions sit below anaerobic threshold, with a small hard share on top. Strength and plyometrics feature, but the block is aerobic first. The mile lives here.
A far larger share of hard, at-or-above-threshold work, plus more strength, power and plyometric training. The 800m runs closer to a power event.
Share of annual running sessions below versus at or above anaerobic threshold. The 90/10 and 60/40 splits, and weekly preparation volumes of roughly 50 to 120 km, are reported by Haugen et al. (2021). The mile sits with the 1500m.
That divide is why a strong 800m runner isn't automatically a strong miler, and why the milers who own the finish tend to carry more of the 800m runner's speed and power into the longer race. It's the thread the companion piece on anaerobic speed reserve picks up.
What to actually train
Build the engine first and hold it, because most of the mile is aerobic and vVO2max sits on top of a big base. Then spend real time on economy, through strength and plyometric work and specific reps, since that's the lever that separates equal engines. Then add the speed and anaerobic top-end the finish demands. Which of the three is holding a given athlete back is the whole question, and it's the one the companion piece on anaerobic speed reserve is built to answer.
The order holds through the year. The base and the economy work carry the winter, the threshold and speed sharpening come as racing nears, and the strength stays in year round so economy doesn't slip when volume drops.
Two cautions before this becomes a recipe. The determinants model is built largely on men, and the samples, even the good ones, are small against the weight of the claims made on them. And VO2max, economy and the anaerobic share are population averages, so the athlete in front of you can sit well off the mean on any of them, which is the reason to test rather than assume. The model tells you where to look. It doesn't tell you what you'll find.
References
- Ingham SA, Whyte GP, Pedlar C, Bailey DM, Dunman N, Nevill AM (2008). Determinants of 800-m and 1500-m running performance using allometric models. Medicine & Science in Sports & Exercise 40(2):345-50.
- Haugen T, Sandbakk Ø, Seiler S, Tønnessen E (2021). Crossing the golden training divide: the science and practice of training world-class 800- and 1500-m runners. Sports Medicine 51:1835-1854.
- Barnes KR, Kilding AE (2015). Running economy: measurement, norms, and determining factors. Sports Medicine - Open 1:8.
- Blagrove RC, Howatson G, Hayes PR (2018). Effects of strength training on the physiological determinants of middle- and long-distance running performance: a systematic review. Sports Medicine 48:1117-1149.
- Sandford GN, Rogers SA, Sharma AP, Kilding AE, Ross A, Laursen PB (2019). Implementing anaerobic speed reserve testing in the field: validation of vVO2max prediction from 1500-m race performance in elite middle-distance runners. International Journal of Sports Physiology and Performance 14(8):1147-50.
All links checked August 2026.