The Pacing Puzzle: Know Your Splits
For years, marathon advice has revolved around three core strategies. A 'positive split' means running the first half faster than the second — the most common outcome for amateurs. An 'even split' involves maintaining a consistent pace from start to finish.
The holy grail for many is the 'negative split', where you run the second half faster than the first. The conventional wisdom has long championed negative or even splits, suggesting a fast start is a recipe for disaster. But as data from millions of runners becomes available, a more nuanced picture is emerging about what works best, not just for elites, but for everyone.
The Peril of a Fast Start
The single biggest mistake most marathoners make is losing the race in the first few kilometres. Adrenaline and fresh legs create a dangerous illusion of ease, tempting you to run faster than your planned pace. Science shows this is a costly error. Starting just 5-10% faster than your optimal pace can deplete your crucial muscle glycogen stores up to 30% earlier. This metabolic overspending early on is what causes runners to 'hit the wall' between kilometres 30 and 35. Research analyzing hundreds of thousands of marathon finishes is stark: the faster you start relative to your average pace, the slower your overall finish time will be.
The Case for a 'Controlled Fade'
While a catastrophic positive split from going out too fast is bad, new analysis suggests that a slight positive split might actually be the optimal strategy for many recreational runners. One massive study of over 4 million marathon results found that while nearly 90% of runners run a positive split, the best performances for non-elites were often associated with a 'controlled fade'—a second half that is only slightly slower (around 1.5-3%) than the first. This contradicts the idea that you must run a negative split to achieve a personal best. The risk with a negative split for amateurs is starting too conservatively and leaving too much to do on tired legs.
Women and Men Pace Differently
A fascinating area of recent research highlights a significant gender gap in pacing. A massive study of the Berlin Marathon from 1999 to 2025 found that men were twice as likely to 'hit the wall' (defined as slowing by 20% or more) than women. The gap was even wider for faster runners; men in the sub-3-hour group were six times more likely to blow up than their female counterparts. Researchers speculate this could be due to several factors, including physiological differences in fuel usage and a greater tendency for men to start too aggressively, while women are generally better at maintaining a steady, even pace.
A Modern Blueprint: The 10-10-10 Strategy
So how do you apply this? A popular modern framework that balances caution with performance is the 10-10-10 strategy. It breaks the race into three parts. The first 10 miles (16km) are run with your head: be conservative and run slightly slower than your goal pace to conserve energy. The next 10 miles are run with your training: settle into your goal marathon pace, which should now feel comfortable and rhythmic. The final 10K (6.2 miles) is run with your heart: use the energy you saved to hold your pace or even accelerate as you head for the finish line. This structured approach is a practical way to aim for a negative or even split and avoid the temptation of a fast start.
