Chances are if you’ve run any sort of race, especially a marathon, then you may have heard other runners tell you that if you can run the second half of the marathon faster than the first half, you can improve your time.  This is known as running a negative split.  The philosophy is you will not burn all the gas in your tank during the first half and have enough glycogen stores left during the second part of the race to run faster.  While this theory makes sense and physiologically can be proven, it really doesn’t hold up for a marathon.

Don’t believe me? Here’s a study that was done by Jonathan Savage comparing the results of 26 marathons covering 876,703 results for 754,851 runners.

CLICK HERE FOR PDF Are negative splits faster in the marathon? An analysis.

He analyzed the finishing times to look at the differences between positive splits (going slower in the second half) and negative splits (running the second half faster).  The results revealed that only 10% of the runners best performances were ran with a negative split. Overall, the data suggests that it’s beneficial to have a split time that is close to even, with a slightly negative split possibly being optimal. The slightly negative split most likely accounts for the elite runners picking up the pace during the last several miles.

Moral of the story, pace yourself and try to run and even pace the entire distance. If you have any gas left, you can use it the last mile or two!  The real challenge is to know what this pace is. Read Phil Maffetones books to help learn pacing by following your heart rate.

Good luck!