With Coach Alexa, Online Running Coach for We Run and the We Run Virtual Running Club
Hi team, Coach Alexa here. Today, I want to talk about pacing strategies for endurance events. This applies to anything from a half marathon to longer races, even including some shorter endurance-focused distances.
Understanding Negative Splits
A negative split is when you run the second half of a race slightly faster than the first.
Some people think this requires a big difference in pace, like a progression run where you start very conservatively and get progressively faster. However, that’s not what it’s about. Instead, it’s relatively subtle – just slightly more conservative in the first half compared to the second.
The Research Behind Negative Splits
The concept of negative splits is backed by data from major marathons like New York, Tokyo, Boston, and London. These events record runners’ splits every 5K and analyse predicted versus actual finishing times.
The findings? Runners who achieved their target times were far more likely to have run the second half of the marathon just a bit faster than the first. Crucially, those who avoided an overly enthusiastic start were less likely to crash or “hit the wall” later in the race.
Why Negative Splits Work
Fuelling and Glycogen Management
One key reason negative splits are effective is their impact on fuel usage.
When you start too fast, your body relies heavily on glycogen – sugars stored in your muscles and liver. However, glycogen stores are limited. Running at a steadier pace early on allows you to burn a mix of glycogen and fat, preserving those vital glycogen reserves for later.
Think of your glycogen stores as a bucket:
- Before the Race: Fill the bucket with proper fuelling.
- During the Race: Top it up as needed.
- Pacing: Controls how much you “open the tap” and deplete the bucket.
If you open the tap too much too early by starting too fast, no amount of fuelling can prevent you from running out of glycogen. This is essentially what happens when you “hit the wall.”
The Psychological Boost
Negative splits also provide a psychological edge. If you’re pacing well, you’ll likely overtake more runners in the second half of the race than are overtaking you.
This creates a positive mental spiral – you feel strong and capable compared to others around you. In contrast, starting too fast often leads to being overtaken, which can feel discouraging and demoralising. You can learn more about my marathon mindset tips in a previous video.
Applying Pacing to Different Events
While this strategy is often discussed in the context of marathons, it can apply to almost any endurance event – running, cycling, even walking.
For races with flat terrain, pacing can be managed with split times or pacers. However, for hilly or trail events, pace becomes less relevant, and effort level becomes the key focus. Monitor your heart rate, breathing, and perceived exertion to stay in the right zone.
“Incorporating negative splits into your training teaches you discipline and energy management, which can make all the difference on race day!”
Coach Priya, We Run Running Coach in Basildon
Conclusion
Starting slightly more conservatively and aiming for a negative split can help you preserve energy, manage glycogen stores, and finish strong. This approach benefits both physical performance and mental resilience, setting you up for success in endurance events of all kinds.
I hope this helps – Happy running!
