Three factors behind race speed

A standard model of running physiology says three things set much of how fast you can race over longer distances, roughly 3K up to the marathon. One is how much oxygen the body can use (VO2max). The next is the share of that you can hold at race pace (lactate threshold). The last is running economy, or how much oxygen each mile costs. The model is widely used but rests more on physiology than on direct tests.

Why it works

VO2max sets the ceiling on how much aerobic energy the body can make. Lactate threshold decides how much of that ceiling you can hold for the whole race. Running economy sets how much oxygen it costs to cover each unit of distance.

What it means in practice

Use this framework to explain what each workout targets. Easy and long runs build the aerobic base, intervals target VO2max, threshold and tempo runs target the share you can hold at race pace, and strength and plyometric work target running economy. Present it as the standard model, not as a measured split of what makes one runner faster than another.

The evidence

• Joyner, M.J. (1991). Modeling: optimal marathon performance on the basis of physiological factors. Journal of Applied Physiology.

  Joyner modeled marathon performance from three physiological factors: VO2max sets the upper limit for aerobic metabolism, the lactate threshold sets the fraction of VO2max that can be sustained, and running economy interacts with both to set the speed at lactate threshold, which is similar to or slightly slower than marathon pace. Combining values reported in elite runners gave estimated times well under the then world record of 2:06:50; the fastest predicted time was 1:57:58 for a hypothetical runner with a VO2max of 84 ml/kg/min, a lactate threshold at 85% of VO2max and exceptional running economy. The author concluded that substantial improvements in marathon performance are physiologically possible, or that current concepts of limiting factors need refinement and empirical testing. This is a theoretical model, not new data.

Why we call confidence medium

Medium: this is the standard framework in endurance physiology, but the corpus support is a theoretical model rather than data on how much of performance the three factors explain. Joyner's 1991 model treats VO2max, the fraction of it sustained at race pace and running economy as the determinants of marathon speed for events longer than about 3,000 m, and the author noted the concepts needed further empirical testing. Jones 2025 argues resilience (durability) is a distinct fourth factor, on limited data.

Where it applies

Adult distance runners in longer events (roughly 3K to the marathon). The model was built on trained-to-elite male values.

Does not apply to: sprint athletes; ultra-endurance events where pacing, fueling, and resilience dominate.