Does strength training make runners faster?
Strength
Yes — but not in the way most runners expect, and the mechanism matters if you want the benefit.
The short answer
Yes. Heavy resistance training and plyometrics improve running economy — the energy cost of running at a given pace — typically by around 2 to 8 percent in the research, with a corresponding improvement in time to exhaustion and race performance. It works by improving neuromuscular efficiency and tendon stiffness, not by building muscle. It does not improve VO2max, and it is not a substitute for running volume. The gains take 8 to 12 weeks to appear.
The three things that determine distance performance
Endurance running performance comes down to three factors:
- VO2max — the size of your aerobic engine
- Fractional utilisation — the percentage of that engine you can sustain, essentially your threshold
- Running economy — how much energy you use at a given pace
Strength training does essentially nothing for the first, very little for the second, and quite a lot for the third. That is why the answer to "does it make you faster" is yes, with an explanation attached.
Why economy matters so much
Two runners with identical VO2max and identical thresholds can differ substantially in race times, and running economy is usually the reason. It is also the factor with the most room to move in trained runners — your aerobic ceiling is quite hard to shift after a few years of training, but how efficiently you use it is not.
A 4 percent improvement in running economy is worth roughly 2 to 3 percent in race time for most runners. On a 3:30 marathon, that is somewhere around four to six minutes. From two gym sessions a week.
How it actually works
Not by making the muscle bigger. Distance runners doing two heavy sessions a week alongside a full running programme gain very little mass — there is not enough training volume or energy surplus for it.
The mechanisms are:
Neuromuscular efficiency. Better recruitment and firing rates mean you produce the required force with fewer motor units, which costs less energy.
Tendon stiffness. A stiffer tendon stores and returns elastic energy more efficiently. A significant proportion of the energy in each running stride is returned elastically rather than produced muscularly, and heavy loading improves how well that system works.
Force at lower relative intensity. If your maximum strength goes up, the force required for each stride represents a smaller percentage of your maximum. Everything feels easier at the same pace.
What the evidence actually says
The research on this is unusually consistent for sports science. Across multiple reviews of trained endurance athletes, heavy resistance training and plyometric training reliably improve running economy and time-trial performance, with no negative effect on VO2max.
What the evidence also shows fairly clearly:
- Heavy loads work; light circuits mostly do not. The stimulus needs to be high-force and low-repetition.
- Plyometrics work, added on top of strength. Jumping, bounding and hopping contribute meaningfully to the tendon-stiffness side.
- It takes time. Most studies show the effect emerging over 8 to 12 weeks. Nothing useful happens in three.
- It does not compromise endurance training when the volume is sensible and the sessions are placed properly in the week.
Coach's note
The honest caveat I always add is that strength work is not the biggest lever available to most runners. If you are running 30km a week inconsistently, adding a gym programme is not the highest-value change you can make — running consistently is. Strength work matters most for runners who are already doing the basics well: consistent volume, sensible easy days, one or two proper sessions a week. If that is you, then yes, two sessions a week will make you measurably faster over a season. If it is not you yet, fix the running first.
The second benefit, which may be larger
Everything above is about direct performance. The indirect benefit is arguably bigger: strength training keeps you running.
The main determinant of long-term running improvement is uninterrupted training. A runner who trains consistently for three years improves enormously; a runner who trains hard for ten weeks and then spends six weeks injured, repeatedly, does not improve at all.
Strength work raises the load your tissues tolerate, which reduces the frequency of those interruptions. That effect does not show up in an economy study, and over a career it probably outweighs the direct performance gain.
What to do if you want the benefit
- Twice a week, 30–45 minutes.
- Heavy compound lifts: 3–5 sets of 3–6 reps at a genuinely challenging load.
- Single-leg work and calf work in both knee positions, every session.
- Add plyometrics after three months: pogo hops, skips, bounds. 40–80 contacts.
- Keep it going through the race build. Reduce volume, not frequency.
- Give it 12 weeks before judging whether it is working.
What about the myths?
"It will make me bulky and slow." Two sessions a week of low-repetition work, alongside a full running programme, will not add meaningful mass. There is neither the volume nor the energy surplus for hypertrophy.
"I should do light weights and high reps because running is endurance." Backwards. Running already provides the high-repetition low-load stimulus. What it does not provide is high-force loading, which is exactly what produces the benefit.
"It will make my legs too tired to run." It will, for a few weeks, while you adapt. Then it stops. Place the sessions on hard days rather than easy ones and this largely resolves itself.
"Elite runners do not lift." Many of them do, and have for decades.
The realistic expectation
Two sessions a week, held consistently for a year, alongside good running: expect a genuine but undramatic improvement in economy, noticeably better durability late in long runs and races, and — most valuably — fewer weeks lost to injury.
It will not transform you in a month. It compounds slowly, invisibly, and without anybody noticing. Which is most of what actually works in this sport.
Put a recent 5k time in and get your easy, threshold and interval paces as real numbers.
Open the pace calculator →I coach a small number of runners one-to-one, in Wellington and remotely, and run AW Extra Mile group sessions for beginners at Waitangi Park. Ask me a question if you are not sure which fits.
