This is one of those topics that I still experiment with now, after all this time doing endurance-type sports. Do I start running faster and then even out as I get to the finish, or do I start slow (so difficult) and then speed up as we progress towards the finish line? And when should I start speeding up or slowing down anyway? But, what does the science say anyway?

A recent review published in Frontiers in Physiology looked at this exact question: whether starting a race slightly slower and finishing faster is actually a good idea, or just one of those things people say while drinking coffee in expensive running shoes!

The paper looked at what is called a negative split. That simply means running the second half of a race faster than the first half. Not dramatically faster. Nobody is suggesting jogging the first 20 kilometers of a Marathon and then suddenly becoming Eliud Kipchoge. Just slightly more controlled early on, with enough left in the tank to keep pushing later. I find this particularily difficult to balance as a purebred 100% certified amateur. I tend to go out way too slow when trying to pace myself, and then find myself overcorrecting too much afterwards. I need to pay really close attention to my pace and heartrate (which is how I track it personally, your miles may vary of course!).

Anyway, here is what the smart people discovered and more importantly…

Watt I’ve Learned

Starting too hard burns through glycogen faster, increases fatigue earlier, and tends to make everything fall apart later. The body starts accumulating stress sooner, heart rate drifts upward, running form gets worse.

A more controlled start seems to help preserve energy, improve temperature regulation, reduce cardiovascular strain, and delay fatigue. So basically you are less likely to completely cook yourself before the interesting part of the race even starts.

The paper also points out that most elite marathon performances are either very evenly paced or slight negative splits. Not huge negative splits. Tiny ones. Which is exactly what I still often fail to do because race-day adrenaline immediately convinces me I am capable of things that, physiologically speaking, I am not 😦

The overall takeaway is not that every race should be a dramatic negative split. The real lesson is that endurance events reward restraint far more often than they reward optimism. Also, negative split “theory” is not a myth, it actually works and you should probably think about giving it a try once to see if it works for you as well.