Yes, probably — but not by the mechanism most people assume. Strength training does not make your engine bigger. It makes the car lighter on fuel.
The three things that determine endurance performance
- VO2 max — the ceiling on how much oxygen you can use.
- Lactate threshold — the fraction of that ceiling you can hold for a long time.
- Running economy — how much oxygen a given pace actually costs you.
Running raises the first two. Strength work acts on the third, and the third is the one most runners never deliberately train.
What running economy actually means
Two runners with identical VO2 max can run very different times, because one of them uses less oxygen to hold the same pace. Some of that is tendon stiffness, some is neuromuscular coordination, some is technique. Heavy strength training and explosive work both appear to improve it.
The practical translation: the same effort produces a faster pace, or the same pace costs less effort and can be held for longer.
How much of an effect
This is where honesty matters more than a confident number. Improvements in running economy from strength training have been reported across a fairly wide range, and individual response varies enormously. What can be said with reasonable confidence:
- Athletes new to strength training see the largest change.
- Well-trained runners who already lift see much less.
- Effects take weeks to months, not days.
- It is additive to running, not a replacement for it.
Anyone quoting you a precise percentage for your specific case is guessing.
What kind of strength work
The distinction that matters is heavy versus light, not machine versus free weight.
- Heavy, low reps (4–6) — the best-supported approach for economy.
- Explosive and plyometric work — jumps, bounds, hops. Also well supported, and complementary.
- Light circuit training (15–20 reps) — the least useful for this purpose. It builds a bit of muscular endurance and not much else.
If you have limited time, heavy compound lifts plus a small amount of jumping covers most of the available benefit.
What it will not do
Strength training will not raise your VO2 max in any meaningful way, will not replace threshold work, and will not fix a training plan with no easy days in it. It is one lever among several, and it is the one most endurance athletes have never pulled.
Common questions
How long before I notice a difference?
Expect neuromuscular changes within a few weeks and performance changes over a couple of months. It is a season-length investment, not a taper trick.
Is plyometric work safe for runners?
It is high-load, so it needs building into gradually and it belongs on a hard day. Start with low-volume, low-height work and progress slowly.
