Negative splits

[Sonic]

I'm always being told to run a negative split, but I've never run a PB this way - my form is to go hard from the start and hold on. Are "negative splits" really a more trusted option?

[Sports Science Editor]

A lot of research and statistical analysis supports the notion that you are more likely to achieve a PB through running a “negative split”. The benefits of running at an even pace or with a negative split are best understood by examining the impact of running the flipside – running the first half of a race faster than the last.

When you try to run a positive split, particularly over long distance, several physiological changes take place – you’ll experience high levels of lactate (leading to heavy legs), oxygen debt and loss of energy. When someone runs a positive split, they lose more by slowing down in the second half than they gain from starting at a quicker pace. It’s also mentally difficult to feel yourself slowing down.

The key therefore to being able to run a negative split is stay relaxed in the first half, then, if you feel good, you’ll naturally be able to speed up.