Marathon pacing is the difference between a strong finish and a painful fade. Many runners start too fast, burn through their energy, and spend the final kilometers battling exhaustion. That strategy is known as ‘putting money in the bank’.
If you want to run your fastest marathon, negative splits - starting slower than your goal pace and finishing faster - are the way to go. But how do you execute this strategy correctly? Let’s break it down.
Why Pacing Matters in a Marathon
The marathon isn’t just about endurance. It’s about energy management. Go out too fast, and you risk burning through your glycogen stores before the final stretch. But pace it correctly, and you’ll have energy left to push when it matters most.
Negative (or even) splits aren’t just theory; they’re backed by elite performances. If you look at the world’s fastest marathons, they follow this strategy.
Elite Examples: The Proof Is in the Splits
Kelvin Kiptum’s World Record (2:00:35, Chicago 2023)
First half: 1:00:22 (2:51/km pace)
Second half: 1:00:13 (2:50/km pace)
His fastest 5K split came between 35K and 40K (14:01 min), just when most runners slow down.
Ruth Chepngetich’s Women’s Record (2:09:56, Chicago 2024)
First half: 1:04:31 (3:03/km pace)
Second half: 1:05:25 (3:06/km pace)
She succeeded in conserving energy early and finished strong, securing the fastest women’s marathon ever. Even I thought she would hit the wall with that fast first half marathon…
If the fastest marathoners in history pace this way, it’s a clear signal this strategy works. Not just for elites, but for any runner looking to maximize their potential.
How to Execute a Negative Split Marathon
Now let’s break it down into a practical pace plan! How should you pace your race?
Pro tip: in most wearables, you can set pacing plans. They'll help you to control your effort - we working on it too!
Phase 1: Start Controlled (0–10K)
Aim to run 5–10 seconds per kilometer slower than your goal pace. Let others race ahead, your time will come. You’ll pass the majority it the latter part of the race. Check your breathing: If it feels (too) easy, you’re probably pacing it right.
Also important: focus on fueling early, don’t wait until you’re tired.
Phase 2: Find Your Rhythm (10K–21K)
Settle into your goal pace (or 1–2 sec/km faster). Monitor your form, hydration, and fueling. Run relaxed, conserve mental and physical energy.
Phase 3: Gently Put the Hammer Down (21K–30K)
Increase your pace by running slightly faster than your previous block. 3 to 5 seconds make a huge difference.
Phase 4: The Strong Finish (30K–42K)
If you’ve paced correctly, you should still feel strong. Keep your pace or even pick it up gradually in the last 10K. The final 5K should feel like your fastest effort. Mentally, remind yourself: This is what you saved energy for.
Common Pacing Mistakes to Avoid
Going out too fast: Feeling good at 5K doesn’t mean you should push harder. Marathons are won in the last 10K.
Ignoring race conditions: Adjust for weather, terrain, and elevation. Running into headwinds? Start even slower.
Not sticking to the plan: Race-day adrenaline is real. Trust your training, not your emotions.
How to Train for Negative Splits
Long Runs with Fast Finishes – Finish your long runs at goal marathon pace or faster.
Progression Runs – Start slow, build intensity, and finish strong.
Race Simulations – During training, practice running the first 10K conservatively.
Trenara’s training plans incorporate all these key sessions to help runners master negative splits. Whether it’s long runs with a fast finish, structured progression workouts, or race simulations, our plans ensure that you develop both the physical endurance and mental discipline needed to execute a perfect pacing strategy on race day.
Pro tip: test your marathon shoes during at least two of your simulation sessions.
Conclusion: Why Negative Splits Win Marathons
Negative splits aren’t just a pacing strategy: they’re a performance advantage. They allow you to finish strong, avoid hitting the wall, and maximize your race potential. Whether you’re aiming for a PR or just want to avoid suffering in the final kilometers, starting controlled and finishing fast is the way to go. It is THE way to unlock your personal best.
