The Truth About “Warm Muscles” in Running: What Really Reduces Injury Risk?

By RunTeach – Pain-Free Performance Through Neuroscience

Every coach has said it at some point:

“Keep your legs warm so you don’t get injured.”

It sounds sensible, it feels intuitive, and every athlete hears it at some stage. But is it actually true? And more importantly, is it true for the reasons we think?

At RunTeach, we look at everything through a brain-first lens, not the old, mechanical model of running. And when it comes to warmth, performance, and injury risk, the real story is both simpler and more interesting.

Let’s unpack what the science actually says — and what matters for real-world running.

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1. Yes, warm muscles perform better… but only above a certain temperature

Research¹ shows that muscles generate more force, absorb impact more effectively, and become more elastic when they reach around 38–39°C. At rest, your quads might sit at 34–35°C.

Here’s the surprising part:

You don’t get to 38–39°C just by putting tights on.
You get there through running at a moderate or hard effort for about 15–20 minutes.

Studies using intramuscular probes consistently show that:

• Light jogging barely moves the needle
• Clothing raises skin temperature, not deep muscle temperature
• The temperature that affects elasticity only happens after sustained effort

So if the old advice was literally true — “warm muscles prevent injury” — you wouldn’t reduce injury risk until the middle of your tempo run!

But athletes feel better long before that, which means something else is going on.

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2. The real reason warmth helps: It improves the nervous system, not the muscles

This is where the myth starts making sense.

Warm legs feel:

• Looser
• More coordinated
• Less “stiff”
• More confident

These changes happen far too quickly to be caused by deep-muscle warming.

They are caused by the nervous system, not the tissue.

Cold skin changes how the brain controls movement

Cold reduces:

• Nerve conduction speed
• Joint position sense
• Reflex timing
• Coordination of hip/ankle mechanics
• Confidence in landing and push-off

And that stiffness you feel when you’re cold?
That’s not tight muscles — it’s your brain increasing co-contraction as a protective strategy.

Warmth sends a “safety signal”

Warm skin improves:

• Sensory clarity
• Proprioception
• Rhythm and timing
• Stride fluidity
• Impact absorption
• Running confidence

Most runners interpret this as “my muscles are warm.”
What’s actually happening is “my brain is happy.”

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3. Injury risk is reduced through “neural safety,” not muscle temperature

Running injuries don’t come from cold muscle tissue.
They come from:

• Poor gait coordination
• Inconsistent movement patterns
• Loss of proprioception under fatigue
• Inefficient impact handling
• Protective guarding
• Stress accumulation from suboptimal control

Warmth helps because it improves movement control, not muscle mechanics.

This is why you can feel “stiff” in the cold even after a warm-up — the tissue isn’t cold, the skin is, and your brain is still interpreting that as threat.

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4. The practical truth for athletes and coaches

Here’s the distilled version:

Warm clothing does not meaningfully warm deep muscles.
But it does improve neural control, which improves performance and reduces injury risk.

So wearing tights or layers is absolutely worthwhile —
just not for the reason most people assume.

The benefits are real, but they are neuro-driven:

• Better movement quality
• Lower co-contraction
• Better proprioception
• More fluid stride
• Enhanced force absorption
• Lower perceived threat
• Improved running economy

In other words:
Warm legs run better because the brain works better when it’s warm.

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5. The RunTeach takeaway

If you want to reduce injury risk, you need to think brain-first, not muscle-first.

Warmth matters, but because of how it influences the nervous system, not because it heats muscle tissue.

When athletes understand this, they stop chasing “warm muscles” and start optimising neural readiness — which is what RunTeach is all about.

1. See the research above ↩︎