Four kilometres down.
One kilometre to go.
Your breathing is hard. Your legs are getting heavy. Your brain is starting to negotiate.
“Maybe just back off a little.”
This is one of the hardest moments in a well-paced parkrun.
So I want you to try something that might sound almost ridiculous when you’re working that hard.
Smile.
Not because the final kilometre suddenly feels easy.
Not because you need to pretend you’re enjoying every second of it.
Use the smile as a deliberate cue to reset, relax and remind yourself that you’re exactly where you chose to be.
Why 4km?
The 4km marker is a useful psychological turning point.
You’ve already completed 80% of your parkrun, but the finish can still feel frustratingly far away.
If you’re running close to your limit, this is also where fatigue can start affecting more than just your legs.
Your shoulders creep upwards.
Your jaw tightens.
Your hands clench.
Your running can start looking increasingly forced.
And mentally, your attention can shift from running well to simply thinking about how uncomfortable you feel.
That’s why I like using 4km as a deliberate reset point.
When you reach it:
Smile. Relax. Reset. Then get back to work.
A Smile Can Be a Physical Cue
There’s actually some interesting research behind this idea.
In one small study involving 24 trained runners, participants completed running bouts while smiling, frowning, consciously relaxing or using their normal attentional focus. The researchers found lower oxygen consumption while smiling compared with both frowning and the control condition, while perceived effort was higher when runners frowned than when they smiled. The researchers suggested that periodically smiling could potentially be a useful cue during vigorous running. (ScienceDirect)
That doesn’t mean smiling at 4km is a magic performance hack. Another study involving collegiate soccer players did not reproduce an improvement in running economy from smiling, so the evidence isn’t strong enough to claim that a grin will automatically make you faster. (Sport & Exercise Science NZ)
For me, the practical value is simpler.
Use the smile as a cue to relax.
Check What Your Body Is Doing
When you smile at 4km, use that moment to perform a very quick check.
Are your shoulders relaxed?
Are your hands loose?
Is your jaw clenched?
Are you still running tall?
Are your arms moving efficiently rather than fighting against you?
You don’t need to spend 20 seconds analysing your running technique.
Smile.
Drop the shoulders.
Relax the hands.
Run tall.
Then focus forward again.
The whole reset might take only a couple of seconds.
Change the Conversation in Your Head
The smile can also interrupt the negative conversation that often starts late in a hard 5K.
At 4km your brain can become remarkably persuasive.
“This hurts.”
“I’m slowing down.”
“I can’t hold this.”
“Maybe today isn’t the day.”
Don’t start negotiating.
Smile instead.
You’ve only got one kilometre remaining.
You’ve already done the vast majority of the work.
Now the question changes from:
“Can I keep doing this?”
to:
“What can I do with the final kilometre?”
That’s a much more useful question.
Don’t Confuse Relaxed With Easy
Relaxing at 4km doesn’t mean backing off.
Quite the opposite.
You can be working extremely hard while still trying to remove unnecessary tension.
Your breathing will still be heavy.
Your legs may still hurt.
Your heart rate may be high.
That’s okay.
The objective isn’t to make the effort disappear.
It’s to avoid adding unnecessary tension to an effort that’s already difficult.
Think:
Hard effort. Relaxed body.
Then Start Racing the Final Kilometre
Once you’ve used your smile as the reset, start breaking down what’s left.
Don’t think about an entire kilometre if that feels overwhelming.
Look ahead.
Can you gradually close the gap to the runner in front?
Can you maintain your rhythm to the next corner?
Can you stay strong for another 200 metres?
Then another?
As you get closer to the finish, gradually turn your attention from holding things together to getting everything you can from what’s left.
You’ve already run 4km.
This is no longer about saving yourself for later.
Later has arrived.
Practise It Before You Need It
Like most mental strategies, this works better if you practise it.
Don’t wait until you’re attempting a massive PB to try it for the first time.
Use it during hard training.
When you’re deep into a Level IV threshold session and tension starts creeping in:
Smile. Relax. Reset.
During a hard Level V interval:
Smile. Relax. Reset.
You can even practise it during ordinary parkruns.
Eventually, seeing the 4km marker can become the trigger.
Instead of thinking:
“Oh no, another kilometre.”
you’ve trained yourself to respond:
“Smile. Relax. Let’s go.”
You Don’t Need to Look Happy
And don’t worry—you don’t need to run the final kilometre with an enormous grin plastered across your face.
This isn’t about posing for the parkrun photographer.
A brief, deliberate smile is enough.
In fact, if there’s a volunteer, spectator or another runner nearby, smiling at them can work beautifully.
It takes your attention away from your discomfort for a moment and reconnects you with one of the best things about parkrun:
You’re surrounded by people sharing the experience with you.
Then it’s straight back to the job.
Bringing It Back to Saturday
At your next parkrun, give yourself one simple instruction before the start:
When I reach 4km, I’m going to smile.
When you get there, regardless of how you’re feeling:
Smile.
Relax your face.
Drop your shoulders.
Unclench your hands.
Run tall.
Then remind yourself:
One kilometre. Let’s see what I’ve got left.
It won’t magically remove the fatigue.
It won’t guarantee a PB.
But it might interrupt that negative spiral, help you release some unnecessary tension and refocus you on finishing well.
And when you’re deep into the hardest part of a 5K, sometimes a tiny mental reset is exactly what you need.
At 4km, smile. Then get back to work.