Runners don't need to lift more. They need to lift heavier.

Walk into most gyms and you'll find runners doing the same thing: high-rep lunges, a few resistance bands, some clamshells, light weights for sets of fifteen or twenty. It feels responsible, and it's better than nothing. But for a runner trying to get faster, it is mostly the wrong dose. The strength work that actually moves the needle looks more like what a powerlifter does than what a circuit class does. The problem isn't that runners need to lift more. It's that they need to lift heavier.

What is strength training actually for?

Strength work does two jobs for a runner, and it's worth being clear about both. The first is keeping you healthy. A lot of running injuries trace back to weak or poorly recruited muscles, particularly around the hips and the back of the body, that can't handle the repeated load of footstrike. Training those patterns is what keeps you on the road, and staying healthy is the single biggest performance lever there is, because the fittest training block is worthless if it ends in the boot. The second job is making you more economical, meaning you use less energy to hold a given pace. That is the one most runners are leaving on the table, and it's the one that needs weight on the bar.

Why heavy, and not light?

Because economy comes from force and stiffness, not from burning your muscles out with endless reps. The research here is fairly consistent: heavy resistance work and plyometrics produce meaningful improvements in running economy, often in the range of three to eight percent, and high-load lifting is especially effective for runners moving at faster paces. Light, high-rep circuits don't build the same qualities. What you want is to lift genuinely heavy, in the range of three to six hard repetitions, which trains your nervous system to produce force without adding much muscle. That last point matters to nervous runners: you will not get bulky lifting heavy for low reps. You will get a stronger, springier stride that costs you less with every step.

Does it actually make you faster over 42 kilometres?

Here I'll be straight, because the honest picture is more interesting than the sales pitch. Most of the strong evidence is on running economy and on shorter time trials, and a few trials have found no clear effect on race performance at all. So anyone promising you a guaranteed marathon improvement from squats is overselling it. But two things tilt this firmly in favour of lifting anyway. The first is newer evidence that strength training improves your performance when fatigued, late in a long race, which is precisely where the marathon is won and lost. The second is the injury-prevention job, which never shows up in a time-trial study but is the difference between getting to the start line fit and not getting there at all. Put those together and the case is clear.

How should you do it?

Keep it simple and keep it heavy. Two sessions a week is plenty. Build them around a few compound movements, a squat or a deadlift variation, a calf raise, something on a single leg, lifted heavy for low reps with full recovery between sets. You don't need much variety and you don't need to chase a burn. As you get close to a goal race, you can pull the volume back so your legs are fresh, but you don't need to stop entirely. The runners who lift like this are quietly buying themselves both durability and a more efficient stride, and over a training year that compounds into real time.