Running Economy: The Other Half of Speed

VO2 max gets most of the attention because it is the ceiling. Race pace is not run at the ceiling. It is run well below it, for a long time, and how far below depends on a second number: running economy.

What economy means

Running economy is the oxygen cost of a given pace. Put two runners on a treadmill at 8 minutes per mile and measure their breathing. One uses 40 milliliters of oxygen per kilogram per minute to hold it. The other needs 46. The first runner is more economical. She is doing the same work with less fuel, the way one car gets better mileage than another at the same speed.

Now give both runners the same VO2 max of 55. The economical runner is holding that pace at about 73 percent of her ceiling. The other is at 84 percent, closer to his threshold, burning more carbohydrate and collecting fatigue sooner. Over a half marathon that gap is minutes. Among trained runners, economy at the same pace can differ by 20 percent or more, which is why VO2 max alone predicts race times loosely among runners of similar fitness.

Performance comes down to three things working together: the ceiling, the fraction of it you can hold, and the cost of each stride. Economy is the third, and it is the one most runners never measure.

What moves it

• Heavy strength training. Squats, deadlifts and step ups at loads heavy enough to limit you to roughly 4 to 8 reps, two sessions a week, have improved economy by a few percent in trials over 6 to 14 weeks. Stiffer tendons and stronger legs return more energy per stride. Light, high rep circuits do not do the same thing.
• Plyometrics. Short hops and bounds train the same spring, and pair well with the lifting.
• Cadence. Many recreational runners overstride, landing with the foot well ahead of the hips, which brakes every step. Raising cadence by about 5 percent shortens the stride and cuts that braking. Any gain in economy is small and inconsistent, and the clearer benefit is less load on the knee and hip with each step. 180 is a common target, not a rule.
• Years of easy miles. Economy keeps improving slowly with training volume long after VO2 max has leveled off.
• Body weight. Extra fat mass is weight to carry with no added engine, so every pace takes a larger share of the ceiling.

How we measure it

The same test that finds VO2 max records it. During the early stages of the treadmill test, below your thresholds, the mask measures how much oxygen you use at each speed, which gives a working read on your economy at those paces. That is your economy at those paces, and retesting after a block of strength work shows whether it moved.

That's why we look at the whole sheet, not just the top number.

This article is educational and is not medical advice.

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