Starting Fast or Negative Splitting: Which Race Strategy to Adopt?

The starting line, the adrenaline, the roaring crowd: we've all felt that urge to shoot off like a rocket without thinking. Yet, the old running adage goes, “start slow, finish fast”—the famous negative split. But is that truly the best strategy? Personally, I've delved into the topic, and world records tell a more nuanced story.

The Three Race Strategies

• Even split — a consistent pace from start to finish. In theory, this is the most efficient strategy: you conserve glycogen and limit lactate buildup.
• Negative split — running the second half faster than the first. Often recommended because it encourages a conservative start and a gradual increase in pace.
• Positive split — running the first half faster. This is what most runners actually do in practice, often unintentionally.

What the Records Say

Looking at the splits for world marathon records, it's quite revealing. Kelvin Kiptum's record (2h00'35) was run with a slight negative split. Kipchoge's in Berlin (2h01'09) also. However, many historical records were run with a nearly perfect even split, with only a few seconds of variation per kilometer.

For 10k and half marathons, the trend is even clearer towards an even split, or even a slight positive split. It makes sense: over these distances, you're unlikely to bonk due to glycogen depletion, and starting at the right pace from the get-go is the smartest move—provided you know what that pace is. A race time predictor based on your recent results can really help you with that.

Why the Positive Split is So Common (and Costly)

Data from major marathons is unequivocal: over 70% of amateur runners record a positive split—often quite pronounced. The Paris Marathon is no exception. The classic scenario: the first 10 km are run 15 to 30 sec/km too fast, and the last 10 km turn into survival mode.

And the thing is, the cost is entirely disproportionate. Starting 10 sec/km too fast over the first 15 kilometers might seem to “gain” you 2 minutes and 30 seconds. But in the last 12 km, you could lose 5 to 10 minutes. The net result is negative—and the feeling is horrendous. We've all been there, right?

How to Apply the Right Strategy

1. Know your target pace — use a pace calculator and a race time predictor to set a realistic pace.
2. Start 5 to 10 sec/km slower than your target pace for the first 3 km — giving your body time to warm up and the crowd to thin out.
3. Find your rhythm between km 5 and km 15 — this is your cruising phase, where you should aim to be as consistent as possible.
4. Manage the second half — if you feel good at the halfway point (the half marathon mark), maintain your pace. If your legs are still responding at km 30, then pick up the pace a bit.
5. Test in training — your long runs at race pace are the time to work on this, not to discover it on race day.

Frequently Asked Questions

What is a negative split?

A negative split means running the second half of a race faster than the first. It's the strategy used in the majority of world records for the marathon.

How do you achieve a negative split in a marathon?

Start 5-10 seconds per km slower than your target pace for the first 15 km, then gradually pick up the pace. Discipline at the start is key.

Is a negative split suitable for all distances?

It's most relevant for half marathons and marathons. For 5k and 10k races, an even pace (even split) is often more effective because the race duration is shorter.

To Go Further

• First Marathon: Mistakes to Avoid
• The Marathon Wall: Understanding and Overcoming It
• Race Tapering: How to Do It
• Race Mental Game: Management Techniques
• Predicting Your Marathon Time: Methods