In the majority of all race situations, running a negative split is the ideal pacing strategy. Yet a study of over 700,000 marathon results found that just 13% of finishers recorded a negative split.
A negative split is a pacing strategy where the second half of your run is faster than the first. Take the example of 10k run. You run the first 5k in 26 minutes, and the second 5k in 24 minutes. Your finish time is 50 minutes with a negative split of 2 minutes. The second half was 2 minutes quicker than the first.
Running a negative split allows you keep some energy in reserve so you can the race strong, confident and power across the finish line with a big smile on your face!
The opposite of a negative split is, of course, a positive split - where the first half of your race is quicker than the second.
An even split is where both halves of the race are very close (0.5%) to being the same time.
In this post I'll cover:
what is a negative split
why run a negative split
advantages of negative splits
disadvantages of negative splits
tips on how to run a negative split
I hope you guys find this info useful and gives you something to consider for your next race. I'm no pro or top coach - just always looking out for ways to improve my performance and get the most enjoyment I can out of each race. And for me, the races which I've enjoyed the most are the ones where I run a negative split.
Let's begin!
WHAT IS A NEGATIVE SPLIT IN RUNNING
A negative split means that you run the second half of your run or race quicker than the first half.
Imagine you are running a 10k race and your target time is 1 hour. A negative split could be: :
0-5k = 31:00
5-10k = 29:00
Negative splits can also be applied to your running workouts and are especially useful for interval-based workouts. Applying negative splits into your workouts will make it easier to run a negative split in your next race.
I'll cover how to include negative splits into your interval-based workouts later on.
HOW BIG SHOULD THE NEGATIVE SPLIT BE
We're not looking for a huge difference here.
For a 10k race, you wouldn't want to run the first 5k in 30 minutes and the second 5k in 20 minutes as this would be hard to execute.
What we're looking to do is negative split by around 1%-3%. For a 60-minute run, that equates to around 30 seconds - 2 minutes.
A study of the best performance from over 12,000 runners who had both a positive and negative split result in a same city marathon shows the majority (52%) had their best result with a negative split.
WHY RUN A NEGATIVE SPLIT
For most of us, we do our runs or events for fun and the challenge.
Coming into the last 2k of your 10k race on your knees isn't much fun and you probably won't be rushing to sign up for your next race.
These are some of the reasons why we struggle at the end of a run.
it's a super hot day
started off too quick
the course is tough
stressed out from work
just not up for it on that particular day
running low on energy
Some of these factors are beyond our control. If we're doing a workout we do have some control over the course and the temperature but not so much in race situations.
We can ensure that we have enough energy to get us through the race and there are ways and means to get motivated.
Starting off too quick is another common mistake for runners of all abilities.
It's a natural feeling, right? You've done your training, you've been counting down the days until the race and now you're on the start line with your adrenaline pumping, feeling fresh and raring to go. In this situation, it's easy to get carried away and go storming off, only to pay for it later on.
Planning for and executing a negative split will help you avoid this.
ADVANTAGES OF NEGATIVE SPLITS
Let's take a closer look at the benefits of running a negative split in your next race or run.
#1 Finish Strong
I'm sure you'll all agree that it's a huge buzz sprinting across the finish line feeling strong and not crawling on your knees. Being able to have a "kick" at the end may even move you up a few places in the final results.
#2 Build Mental Discipline
It takes a lot of self-discipline to stick to a sensible pace at the beginning of a race and resist the urge to go tearing off as quickly as possible.
It's natural to feel uneasy as other competitors come past you - but trust in your plan and think of it as a little game. You've passed me now, but I'll get you later!
#3 Help Avoid Injury
When we get tired, our running form suffers, which increases the chance of injury.
Studies have also shown that when you get tired, your cadence slows and your stride length increases, raising the oxygen cost of running and further amplifying your fatigue. It's like a vicious circle that you want to stay away from!
#4 Delay Lactic Acid
We want to slow down the build up of lactic acid for as long as possible so we can maintain our race pace. Starting slower allows you to delay the onset of lactic acid production and low oxygen levels that result from heavy exercise.
#5 Build Confidence
Remember that buzz as you powered across the finish line? I bet you wanted to get signed up for your next race straight away and tell everyone about what a great race you had. Finishing quicker will fill you with confidence that you can go even better next time.
#6 Overtaking
Even though our main goal may not be finishing in the top 25%, the feeling of overtaking other runners at the end is a good one!
Especially if they are runners that came past you earlier on that you have now caught and passed!
#7 Avoid Hitting the Wall
Ok, so running a negative split isn't necessarily going to mean that you'll never hit the wall!
But employing a proper pacing strategy that allows you to get stronger at the end should reduce the likelihood.
Hitting the wall is not a good feeling. I know. I've been there!
In the 2019 Ironman 70.3 Thailand, I went off far too quick on the run leg and was completely spent with about 5k of the run remaining. I was being passed by loads of other runners and was having to walk at times. Not a good feeling!
There were many other factors that contributed to that such as the heat and lack of proper preparation, but going off to quick at the start of the run and not sticking to my race plan certainly had a big impact.
DISADVANTAGES OF NEGATIVE SPLITS
So, that takes care of the benefits of running negative splits, but there are some disadvantages and things to be wary of if you are planning a negative split race.
Leave Gas in the Tank
With a negative split, there is the the potential to finish the race with too much gas in the tank.
While we want to finish strong and be able to put in a good sprint at the end - we also don't want to feel that we could have gone harder and quicker.
And in a race situation, there's always the possibility that by starting off to slow, you allow your other competitors to get too far ahead and you can't catch them at the end.
The Course
If the course you're running on is hilly, then it might not be feasible to run a negative split. If the first half of the race is downhill, and the second half has more uphill sections, then you're naturally going to run the first half faster.
Learning more about the course can help prevent going out too quick and not leaving enough energy for the uphill parts. Try to find out how long and how steep the hills are prior to the race. If possible, do a reccy of the course.
DO ELITE ATHLETES RUN NEGATIVE SPLITS
Lets have a look at some of the most famous and best performances by elite runners over the years.
Eliod Kipchoge's marathon world record
First 21.1k = 61:06
Last 21.1k = 60:33
Finish time = 2:01:39
Negative split of 0.9%
Mo Farah World Champs 2017
First 5000m = 13:36
Last 5000m = 13:13
Finish time = 26:49
Negative split of 1.42%
From our study of the best performance for runners with both positive and negative splits, a whopping 69% had their best performance with a negative split.
HOW TO RUN A NEGATIVE SPLIT
It sounds easy but actually running a negative split is a bit harder than we imagine!
An additional study by Strava show that the number of runners who negative split marathons is staggeringly low, usually falling between 1 and 8 percent of finishers.
This is because our natural instincts are to set off at a fast pace.
Here are 4 TIPS that hat can help you get a negative split in your next race and start reaping those benefits!
1. Train with Negative Splits
What you do in training is replicated in your races. Aim for a majority of your training runs to include a negative split.
Negative splits in training can be applied to easy runs, long runs or even tempo runs.
If you're doing a 5k run, aim to get faster with each kilometre.
For a longer run, say a 12k, look to speed up in the final 2-3k.
For interval based workouts, such as 6 x 1k repeats, you may try to run the last 2 quicker than the first two.
This is going to help tune your mind and body into the need to go faster at the end of a race.
2. Start off Easy
Far too often we set out on runs all guns blazing, only to be completely spent by the last few k's and come staggering home with poor running form and out of breath.
Start the run with an easy pace.
To get an idea of what an easy pace to start with is, we need to identify what our race goal is.
3. Set a Realistic Goal
Any run, whether it be in training or a race, must have a realistic goal.
Nate Helming from The Run Experience suggests setting 3 goals for your next race.
everything went perfect. Trained well. Prepared well. Felt great on race day
had a few minor problems, still performed well in race day
some problems in training, stress, busy at work/family but I finished and survived
How do you plan your goals?
4. Plan your Splits
Once you have a target time, you can begin planning your split times.
You could do this in your head with a pen and paper, or you can use a negative split calculator to do the hard work for you!
Let's use our example of a sub-hour 10k race, with a negative split of 3%.
Here we can see that our average pace needs to be 5:59 min/km.
And below we can see the splits for each kilometre.
In this example, the first 5k takes 30:22 and the second 5k takes 29:23
These days there are many good value and low-cost sports watch that displays your pace, for example the KIPRUN GPS 550 by Decathlon.
4. Stick to Your Race Plan
You've got your target time and your splits - now you just need to stick to the plan!
Final Thoughts
Running a negative split can be a highly useful pacing strategy when applied and executed well.
It's by no means a one-size fits all method and it can't necessarily be used in every run or race that you do.
From my experience, the races which I have enjoyed the most and had my best results are the runs or races where I have successfully run a negative split.
I'd love to hear your thoughts on this strategy. Do you agree with it? What other advantages or disadvantages have you found with a negative split strategy.
I hope this has been useful for you guys and given you some food for thought.
