Why Your Hips, Knees & Ankles Start Hurting in the Final Part of a Marathon

You’ve trained consistently.

You’ve fuelled properly.

You felt strong for the first 25–30km.

And then it happens…

Your knees start aching.

Your hips feel tight.

Your ankles stiffen up.

Most runners assume this is just “fatigue", but that’s only part of the story.

It’s Not Just Fatigue — It’s a Loss of Durability

What you’re experiencing late in a marathon is often a breakdown in durability.

Durability is your ability to:

• Maintain good running form

• Continue producing force

• Stay efficient under fatigue

You don’t just need to be fit enough to run the distance; you need to be able to hold your mechanics together when your body is under stress.

What’s Actually Happening in Your Body

As the race progresses, two key types of fatigue build up:

1.⁠ ⁠Neuromuscular Fatigue

This is your brain’s ability to communicate with your muscles effectively.

As fatigue increases:

• Coordination drops

• Timing becomes less precise

• Stability decreases

2.⁠ ⁠Muscular Fatigue

Your muscles lose their ability to:

• Produce force

• Absorb impact

• Control joint movement

This is especially important in a marathon, where every step places a load on your system tens of thousands of times.

Why Your Joints Start to Ache

When your muscles fatigue, they stop doing their job properly.

That leads to subtle (but important) changes in your running:

• Increased hip drop

• More knee collapse (valgus)

• Reduced ankle stiffness

• Longer ground contact time

These changes might be small, but over thousands of steps, they add up.

👉 The result: more load gets transferred to your joints

Instead of muscles absorbing and controlling force, your:

• Hips

• Knees

• Ankles

…start taking more of the strain.

That’s when you feel that familiar late-race ache.

Why It Only Happens Late in the Race

Early in the marathon:

• Your muscles are fresh

• Your coordination is sharp

• Your form is efficient

But as fatigue builds:

• Force production drops

• Control decreases

• Mechanics break down

This is why the final 10–12km can feel like a completely different race.

It’s not that your fitness suddenly disappeared; it’s that your body can no longer execute efficiently under fatigue.

How to Improve Your Durability

If you want to reduce late-race aches and hold your form longer, your training needs to reflect it.

1.⁠ ⁠Strength Training

Focus on:

• Heavy strength work (for force production)

• Eccentrics (for load absorption)

• Calf, quad and hip strength

Stronger muscles = less load transferred to joints.

2.⁠ ⁠Train Under Fatigue

You need to prepare your body for the exact demands of the marathon.

Include:

• Long runs

• Fast finishes

• Marathon pace work at the end of runs

This teaches your body to maintain mechanics when tired.

3.⁠ ⁠Plyometrics & Reactive Work

These help improve:

• Tendon stiffness

• Elastic energy return

• Neuromuscular timing

All key for maintaining efficiency late in the race.

4.⁠ ⁠Consistency Over Time

Durability isn’t built in a few weeks.

It comes from:

• Consistent mileage

• Progressive loading

• Staying injury-free

The Takeaway

Those aches you feel in your hips, knees and ankles late in a marathon aren’t random.

They’re a sign that:

👉 Your muscles are no longer absorbing and controlling load effectively

👉 Your joints are picking up the slack

Fitness gets you through the early stages of the race.

But durability is what carries you to the finish line.

If this sounds familiar to you, getting your gait analysed online or in-person (Liverpool Street) is a great place to start.