December 23, 2025

Strength Training for Marathon Runners: Why It’s Non-Negotiable

If you’ve been running consistently for a while, chances are you’ve had this thought: “I know I should be doing strength training… I’ll get to it.”

You’re not alone. Many marathon runners sit in this middle ground, motivated and logging regular miles yet still relying almost entirely on running itself to prepare their body for the demands of marathon training.

As we look ahead to the next season of training and racing one thing is clear: strength training isn’t optional anymore. It’s a fundamental part of improving running performance, staying healthy and continuing to progress year after year. Join us now as we delve into running and the importance of strength training below, written by our Chartered MSK Physiotherapist Leila Todd.

Why marathon runners need strength training, not just running

Running makes you better at running but it doesn’t automatically prepare your body to tolerate high mileage, long runs and cumulative fatigue.

“As a physio, I see runners who are incredibly fit from a cardiovascular point of view, but their bodies are struggling to keep up with the load,” I often explain. “They can run the distance but they can’t always handle it.”

Without adequate strength, mobility and correct running technique, the same tissues end up absorbing stress repeatedly. Over time this will lead to niggles appearing, performance plateaus, or injuries interrupt training blocks entirely.

Why generic strength training fails marathon runners

Most runners know strength work matters so they research a plan tailored to runners, add a few exercises minimum once or twice a week and hope it balances things out.

The problem is that not all runners break down in the same way.

“Two runners might be training for the same marathon, on similar mileage, and still develop completely different issues,” I say. “That’s because the root cause usually isn’t the miles it’s how their body moves and manages load.”

This is where a RunFit assessment becomes a game-changer. Rather than guessing, it identifies individual weaknesses and movement patterns that strength work can transform and improve overall running capacity.

How strength training improves marathon performance

Strength training isn’t about replacing runs or spending hours in the gym. It’s about supporting your running, so it becomes more efficient, more consistent and more sustainable.

• It improves efficiency
• Strong hips, glutes, calves and trunk muscles help you maintain form as fatigue sets in particularly in the later miles where performance often drops.
• It reduces injury risk
• Strength increases your tissues’ ability to tolerate load, reducing stress on joints and tendons as training volume increases.
• It supports consistency
• Fewer niggles mean fewer missed sessions and consistency is one of the biggest predictors of marathon success.
• It builds confidence
• When your body feels robust, you can progress training without second-guessing every ache or pain.

How a RunFit assessment improves marathon performance

One of the most common things runners say after a RunFit assessment is: “I didn’t realise that was my weak point.”

“That moment of awareness is powerful,” I tell my clients. “Because once you understand how your body moves, strength training stops feeling random and starts feeling purposeful.”

A RunFit appointment includes:

• Strength, mobility and gait assessment to understand how your body handles load
• Biomechanical movement analysis to identify inefficiencies or compensations
• A personalised injury-prevention plan, including targeted strength work to support your training

Rather than adding more to your plate, it helps focus your effort where it matters most.

Realistic strength training for busy marathon runners

Marathon runners aren’t professional athletes and they don’t need to train like them. What they do need is a smart, realistic structure that fits around life, work and long-term goals.

“You don’t need to be in the gym everyday” I often say. “You need the right exercises, for your body with progressive loading throughout your training block”

For most runners, two focused strength sessions per week aligned with mileage and recovery can make a meaningful difference when they’re tailored correctly.

Train Smarter for Your Next Marathon, Not Just Harder

As runners continue to chase bigger goals and race calendars, the demands on the body will only increase. Strength training is what allows runners to meet those demands without breaking down.

The question isn’t whether you should be strength training it’s whether you’re doing the right strength work for your body.

At Bodyset, we support runners end-to-end from niggles and injury recovery to marathon performance. Our physiotherapists don’t just talk about best practice; we apply it every day with the runners we work with.

Because running more miles isn’t always the answer. Sometimes, real progress often starts with getting stronger first.

Book your RunFit assessment today at one of our 35+ Bodyset clinics nationwide.

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