Why Negative Splits are Important

Sunday, April 02, 2017 · Mike Davis

Good morning!

Hopefully the poor start to April for some of you will not dim your enthusiasm for the wonderful days ahead of you all. Take heart, maybe by this time next week, the green will be the dominant color! In any event, grab your coffee and pull up a chair.

The past week was a great success for yours truly, as I got in 3 runs and for good measure also strength trained one time. Not a perfect week, but one I will use as encouragement for the week ahead.

As I chatted about Friday, I utilized heart rate to guide me through an interval workout and yesterday I again used heart rate to pace me through my long run. This time my goal was to stay aerobic (zone 3) for the entirety of my run, in hopes of running longer at greater comfort. Staying aerobic helps our metabolic system rely primarily on utilizing fats as our fuel and by far we have more stored fat than glycogen (carbohydrates) at our disposal. This workout may sound like a weight reduction idea based on the description and though it sounds like it would be, that is not the case. Running in your fat burning zone (aerobic), primarily allows a runner to utilize stored fuel (fats mostly), that we have more available to us. When we speed up and move into the next zone (anaerobic), we rely on glycogen as our fuel source, and we have much less of that available to us. If we stay at that pace long enough, we will lose our endurance much sooner and it is pretty much impossible to recover it.

When we draw up a strategy for a race, we most often attempt to have our runners, run negative splits. Meaning, start off at a slower pace and as the race progresses, pick up the pace incrementally. This strategy essentially allows the runner to stay aerobic early, and as they speed up they move into a combined aerobic/anaerobic and as they get in to the final stages, they go totally anaerobic and are able to finish strong. The flipside is when we get caught up with the race crowd or we do not control our adrenalin and start out at a pace that keeps us in aerobic/anaerobic for a good part of the early race. Now we have utilized our glycogen and have only our fats to fuel us and that is when our run ends up getting slower and slower. It is obvious which strategy is more beneficial, yet most runners have been guilty of this error. We coach our runners to be disciplined and trust that if they manage their pace they will have the needed fuel to enjoy a great run.

There are sources of nutrition that certainly help us as we prepare for a race or run as well as some that we can utilize during the run. However, none of them will return the depleted glycogen to the level we need, once we burn it. Better to combine smart disciplined running with good nutrition, for a strong and enjoyable run. This is not only about a race, but also for any run of any fairly long distance (2 miles on up). If you are running an 800 meter distance only, you can get into anaerobic quickly and if you are in decent shape, chances are you will finish the distance about the time you deplete your fuel (glycogen). However, since we focus on greater distances, we must focus on maximizing our fuel consumption.

I hope I didn’t bore you with the science of running, but I tried to keep it simple and relative to our goal of enjoying our running. There are various different goals to our running and we can understand some of the science, we can positively impact all of our goals.

Have a great Sunday and super week!

God Bless!

Mike