18 Jul

The Science of Sprint Finishes

Two runners in a sprint to the finish line

Why is that even at the end of a gruelling long-distance race, we are able to conjure up a final sprint finish? After enduring fatigue for miles on end, suddenly we can find a fresh surge when the finish line comes into sight?

On the face of it, it’s strange that someone hitting a wall in the marathon at 18 miles, can still muster a final burst in the dying metres of a race. Yet, from the speedy bucks at the front to the steady Eddies at the rear, it’s a constant across all organised races.

So, why does it happen?

Mental strength? The urgings of the crowd? Yes and yes - but there also are sound scientific reasons behind the human ability to dig deep. The body switches between systems to meet the intensity level of the activity.

During endurance activities, the body relies almost entirely on the aerobic system. It’s a – relatively – low intensity exercise that requires adequate oxygen to the working muscles. The aerobic system can use carbohydrates, fats, or proteins to produce energy.

But when the intensity ups, the body needs to switch to systems that are not over-reliant on oxygen. It can rely on a lactate system for 1-3 minute sustained activity before performance depletes. Or for maximum intensity and short bursts of five seconds, the phosphagen system, where creatine fuels the activity before quickly running out.  

Runners at all levels will experience the switch of systems. The aerobic system will maintain performance for the bulk of a run, but a sustained hill might call upon the lactate system and the sprint finish the phosphagen system.

From a runner’s perspective, I am well familiar with all. There is little more rewarding than tapping into your alternate systems and picking off a few places in a sprint finish.

Though I can recall one occasion where I outsprinted a fellow runner, only to realise I had misjudged finish line to be 10 metres earlier than it actually was. Unfortunately, you can’t go back to that sprint finish right away and I had to jog over the line, pride bruised, but lesson learned. System fine...user error.