The fastest Olympic sprint was Usain Bolt’s 100 meters at the London Games, averaging more than 23 miles per hour for 9.63 seconds. Marathoners, who run for two hours, top out around half of Bolt’s speed.

The 100-meter and the marathon are at either end of the Olympic spectrum of running races. The sprints (100, 200 and 400 meters) are strictly about power and mechanics. The endurance races (1,500, 5,000 and 10,000 meters and the marathon) are all about the supply and demand of energy. The 800-meter race, while just two laps around the track, sits between them, the painful middle ground between a pure sprint and pure endurance.

Average Speeds by Event

at World Record Pace

Average Speeds by Event

at World Record Pace

We invited three elite runners to run on the world’s fastest treadmill — at the Locomotor Performance Laboratory at Southern Methodist University — to examine the differences between running fast and running far (but still pretty fast).


‘Pulses of force
into the ground’

The common thread in all the events is speed. In the end, it’s the only measure that matters; whoever crosses the finish line first wins. There is a single factor that determines a runner’s speed, regardless of distance: how much force they deliver into the ground relative to their weight, said Peter Weyand, the director of the lab at Southern Methodist University and one of the world’s foremost experts on how to run faster.

Contact Time

‘Sprinters are in the air most of the time’

How long the foot is on the ground during each stride determines how the runners move. Sprinters create their forceful strides by accelerating their leg quickly to the ground to make sure it hits at peak velocity. The foot makes quick contact and gets off the ground. An elite sprinter’s ground time is less than a tenth of a second.

For the marathoners, it’s about 130 milliseconds or more. “What they want is to make it as easy as possible so they burn the minimum amount of energy to get the force down that they need,” Weyand said.

The charts below show the pattern of force these runners make during the length of their stride. It illustrates the different requirements each of the race distances place on the athletes who run them. Notice how different the shape of the sprinter’s chart is compared with that of the marathoner. And how the chart of the 800 runner reflects aspects of the other two.

Stride Length

‘Each limb has to go through 12,000 cycles’

An elite sprinter will cover a lot more distance between each step than an endurance runner. Long strides cost a lot of energy over time for a marathoner, who will take about 12,000 strides per leg during a race. Each one of those individual muscle contractions uses energy. A 100-meter male sprinter will take only about 45 strides and a female sprinter about 50.

Leg positioning

High knees for sprints; Low knees for distance

Anyone running at their top speed, including you and Usain Bolt, share at least one thing: The time between when a runner’s foot comes off the ground and when the same foot hits the ground again is about a third of a second. Yes, that’s true for everyone. But what the leg does in the air is very different depending on the length and speed of the race.

A sprinter can’t let their leg come very far behind the body before picking up their foot. In that third of a second they have to get their front knee high to create the necessary force into the ground. A distance runner is the opposite: they can let their leg go farther behind them. They have more time to reposition it because they don’t need to have a high knee lift.

Aerobic vs. Anaerobic

The Agony of the 800

There are largely two kinds of runners who are showcased at the Olympics: the powerful sprinters and the efficient distance runners. And each group mainly has its own energy system: Aerobic for the distance runners, anaerobic for the sprinters. But where these two groups overlap — the 800 meters — lies a race many want to avoid. Ask a competitive runner what their least favorite race is, and they will likely say it’s the 800 meters.

Endurance races are considered aerobic because virtually all of the energy for the races come from the use of oxygen in the body. Elite marathoners, for example, have trained their bodies to be extremely efficient at processing oxygen for fuel.

But for each runner, there is a maximum limit to the rate at which oxygen can be used. That’s called their VO2 max, which is an important measure in predicting how fast an endurance runner can go for the duration of their race.

Running at a certain level below their maximum limit allows distance runners to sustain their race pace for long periods of time. For elite distance runners, the level under VO2 max changes according to the length of the race, but is strikingly similar among athletes in the same race. That’s why at the Olympics you will see large packs of athletes running at the same pace.

Percent of VO2 Max, by Distance

Percent of VO2 Max,

by Distance

Note: Data shown are measurements for typical elite runners in each race. The share of VO2 max is not shown for 100- and 200-meter runners because they are almost exclusively anaerobic events.

Sprint races, on the other hand, are considered anaerobic. Although sprinters also use some oxygen as a fuel source, it does not determine their performance. Instead, they burn glucose and use energy already stored in the muscles. But that fuel system has its limits too. Once it creates more lactate than the body can expel, the muscle burning and cramping begins.

The 800 meters lies at the painful intersection between the aerobic and anaerobic races. The race requires both systems of energy: 800 runners rely heavily on aerobic metabolism, but they also have to sprint.

With both fuel systems being taxed, the body undergoes two types of stress, leading to agonizing descriptions of the race: “Psychotic.” “Painful.” “I would never run the 800.”

It’s the only race that elicits this kind of universal reaction. So have sympathy when you’re watching the 800-meter runners in the Olympics. It’s the race they were destined for: not fast enough for the sprints; not enough endurance for distance races.

As Ward put it, “Sometimes our distance chooses us.”

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