Are Negative Splits the Key to a Faster Race Time?

If you watch a motor race, you might notice that the cars get faster toward the end. Because they start out with a heavy fuel load and burn it over time, they get lighter, enabling them to gain more speed on each lap. Although a human body and a racecar are nothing alike, you also have the ability to speed up over the course of a race, whether it be a 10K or a half marathon. It takes work to do so, but it’s worth the effort if your aim is to finish stronger and faster than you thought possible. 

What Are Splits?

In running, a split is the time it takes you to run a portion of a given distance. For example, if you’re running a 5K, you’ll look at your times for miles one, two, and three, with each of those being a split. In this type of race, you ideally want to see your times holding steady from mile to mile. 

However, if you’re preparing for a longer race, such as a half marathon or marathon, individual splits won’t necessarily tell the whole story. Instead, group your splits into larger chunks to get a better sense of your overall performance. This can be key to clocking your best possible time come race day.

What Is a Negative Split in Running?

Achieving a negative split simply means that you ran the second half of your race faster than the first half. For example, in a 10K, that would mean your second 5K was faster than your first. While that might sound difficult—and it can be—it’s not as impossible as it may sound.

“We typically use the first few miles to get the body and the breath properly warmed up and adjusted to the distance of the run,” says Peloton instructor Mariana Fernández. As a result of your slower starting pace, you’ll set yourself up to have the energy in the latter half of your race to increase your speed. 

In addition to helping you hit your goal time, chasing negative splits can also help you pace effectively and efficiently. “I have found that we can easily let nerves, adrenaline and excitement shoot us like cannons out of the start line,” Mariana says. “It can be demoralizing and downright painful to use all of your fuel and suffer the second half of the race. If you learn how to measure and conserve early on, it gives you the freedom and fuel to shift gears and finish stronger than how you started.”

How Much Emphasis Should You Put on Negative Splits in Your Training?

If you’re currently in the throes of training, you likely want to deliver your best performance. So how much should achieving a negative split factor into your training? Short answer: It depends. 

Take, for example, intervals. In these sprint-oriented workouts, you can practice finishing fast to replicate how you may clock a negative split on a long run or during your race. Mariana says you can try running one of your fast intervals, note the time, and then on the next fast interval, aim to beat that time. The same ritual can be replicated during a hill workout. “You can practice not going all out on the first hill and finding that sense of control and conservation,” she says, “then see if you can go faster or attack the last hill of your run.”

However, not every workout needs to be centered around negative splits. “Some races and training runs are you just getting to know your body and your paces,” Mariana says. “A lot of training runs and even some races will be trial and error.” 

You might find that negative splits aren’t feasible for you—and that’s OK. Several factors can inhibit your ability to run faster within a set of intervals or over the course of a long training run, including dehydration, the outside temperature, your sleeping habits, and what you ate before your run. 

“It really comes down to syncing with your body during the run to see when you do have the drive to access speed and strength in the second half of your run,” Mariana says, “or if you have to back off to keep your body safe and stay in it.”

Can You Use Negative Splits to Get Faster?

Yes. However, be careful to not go too slow at the start. It takes practice and constant monitoring of your splits on training runs to learn how to properly pace yourself.

“Negative splits are really about knowing how to pull back and take your time to find different pace targets,” Mariana says. “There is a proverbial ‘wall’ that you can hit if you overdo it in the beginning or even in the middle. That can truly affect the way and speed [with which] you finish the race.”

If achieving a negative split feels out of reach as you analyze your training runs, Mariana suggests trying a “controlled fade.” Instead of getting faster over the course of your race, your splits will get (slightly) slower. Some research indicates that, if you’re more of a recreational runner, this can be a better way to clock a faster race-day time compared to a strategy centered on negative splits. You’re not ignoring your splits in a controlled fade, you’re just managing them differently.

How to Use Negative Splits to Your Advantage 

Taking advantage of negative splits is all about using your training runs to better understand your body. If negative splits don’t seem feasible during training, they probably will feel the same way on race day. If that’s the case, try a different—and possibly more effective—strategy for you, such as a controlled fade. But if you do decide to go after that negative split, Mariana stresses that it’s important not to get overconfident. 

“Pull back in the beginning, ease into the comfortable pace, and then enjoy the energy you have toward the end,” she says. And she’s learned the hard way: Oftentimes, the more confident she got in a race, the harder she pushed herself in the first half, leaving her expended by the end. “The last few miles, I had burnt out my reserves and had little to no power to finish the race,” she says. “The last moments felt like a shuffle or a white-knuckling to get to the finish line, and the aftertaste was just misery.”

In other words, expect some ups and downs as you try to achieve a negative split and a faster race-day result. As you train with a negative split in mind, consider it “a check-in with your body and your ability to stay steady enough throughout,” Mariana says. By tapping into your mind-body connection, on race day, you’ll “have the ability to shift into speed and power at the end and have a strong finish.”