When I finished my half marathon I couldn’t believe how much of a slog it was.
Far from finishing strong, I found myself tiring between miles 9 and 13 and as a result my mile times and overall race time suffered.
I later found out that this is where negative splits can help!
How you run a race is just as important as how you finish a race.
In order to finish strong, you can’t just expect to attack the race from the very beginning and achieve your next PB.
Even elite athletes use race strategies like negative splits to improve their race times.
But what exactly are negative splits and how can they help you to run faster, and more importantly, happier?
In this guide we’ll explore:
- What are negative splits?
- Negative splits vs positive splits
- What are the benefits of negative splits?
- How do you train to run negative splits?
- How to run a negative split to smash your next PB
- 5 negative split workouts to try
Ready?
Let’s get started!
What is a negative split run?
Negative splitting is a pacing strategy used in races by both elite and amateur athletes.
A negative split run is when you run the second half of the race faster than the first half, so you finish the race faster than you started.
Let’s take a look at a few examples:
- If you run a 5k (3.1 miles) in 25 minutes and run the first half (1.55 miles) in 13 minutes and the second half (1.55 miles) in 12 minutes, you’ve run a negative split.
- Likewise, if you run a 10k (6.2 miles) in 45 minutes and you run the first half (3.1 miles) in 24 minutes and the second half (3.1 miles) in 23 minutes, you’ve run a negative split.
Related: How to run an 8 minute mile: 8 ways to run faster
Negative splits vs positive splits
When you complete the first half of a race faster than the second half, this is known as positive splitting.
While negative splitting seems to get all the attention when it comes to pacing strategies, there are times when positive splitting can yield the best results.
One study found that in order to optimise performance during a 5k run, runners should start the initial 1.63km at paces 3 to 6% greater than their current average race pace.
However, for longer distance runs like the marathon, positive splitting has been shown to be detrimental to running performance.
By running the first half of the marathon faster, research has shown there is increased oxygen consumption, a higher level of fatigue and an increased rate of perceived exertion (RPE).
The bottom line? Positive splitting may yield better results over shorter distances like the 5k.
Whereas negative splitting is considered a better pacing strategy for longer distances like the half marathon and marathon.
Related: How to pace your run: 4 simple tips for effective pacing
What are the benefits of negative splits?
There are many benefits to negative splitting.
#1 They’re easier to manage
Arguably, negative splits are easier to manage compared with other pacing strategies like positive splits.
This is because it’s easier to run faster in the second half of a race once your body has fully warmed up.
During the first few miles of a race, particularly in long distance races, your body needs time to adjust.
You are also more likely to experience higher levels of fatigue if you run the first half of a long distance race faster than the second half.
#2 They boost your confidence
Every runner will agree when I say that it feels good to finish a race strong.
You leave the finish line with a sense of fulfilment, satisfaction and achievement and it leaves you wanting more!
Negative splits are great for boosting your confidence in this way.
#3 They’re better for faster race times
Many national and world running records have been run using negative splits.
This goes to show that negative splitting is an effective pacing strategy in order to achieve faster race times.
Ethiopian long distance runner Tigst Affesa obliterated the women’s marathon world record with a time of 2:11:53 in Berlin in September 2023.
Assefa ran the first half in 66:20 – more than a minute ahead of the world record pace.
She ran the second half in 65:33 – which would have stood as the world record in the women’s half marathon a decade ago.
The numbers really are hard to comprehend – here are Assefa’s split times.
You can see between 20k and 40k her split times get progressively faster.
- 5k: 15:59
- 10k: 15:46 (31:45)
- 15k: 15:41 (47:26)
- 20k: 15:26 (1:02:52)
- 25k: 15:48 (1:18:40)
- 30k: 15:32 (1:34:12)
- 35k: 15:29 (1:49:41)
- 40k: 15:32 (2:05:13)
Assefa ran her final 2.195k in 6:40 (15:11 pace or 4:53/mile pace).
Overall, her world record time averages out as 5:01 per mile for the full 26.2 mile distance which is just mind boggling.
Related: What is a good half marathon time? Average half marathon times by age and gender
How do you train to run negative splits?
The key to running negative splits is to get comfortable with them during training.
They require much more effort in the second half compared with the first half.
Therefore you need to get your body (and mind) comfortable with running at a faster pace during the latter half of the race.
This often equates to workouts that allow you to practice pacing in a training environment.
The best way to do this initially is to run an easy distance and finish faster than you started.
Try running a 5k or 10k and see how it feels when you finish the second half of the run faster.
This doesn’t mean adopting a super fast pace so that you can hardly feel your legs.
Try a slow pace in the first half to begin with and then adopt a more moderate pace in the second half.
Once you have experimented with this over a few weeks, you can then start doing more structured workouts.
At the end of this guide you will find three sample workouts to try.
Related: What is a good 10k time? Average 10k times by age and gender
How to run a negative split to smash your next PB
Accurate pacing only works when you first understand what you’re capable of.
In other words, what pace is realistic for you?
The last thing you want is to start a race too fast, so by the time you get to the halfway mark, you succumb to tiredness and fatigue and can’t finish the race.
To work out your negative split times, you first need to work out your average race pace.
Think about your previous race times as these will be a good indicator of what you’ll be able to achieve.
Let’s say you want to run a half marathon in 2 hours. This means your average race pace will need to be around 9:10 minutes per mile.
It would therefore be sensible to run close to this pace for the first half of the race, then adopt a faster pace during the second half.
How fast depends on how comfortable you feel.
The general rule of thumb is to make the negative splits no more than 10% faster than your average race pace.
You may want to use a negative split calculator to help you work out your split times.
So if we take the average race pace of 9:10 minutes per mile and make the negative splits 5% faster, your mile split times could look like this:
| Mile | Split time | Lap time |
| 1 | 9:36 | 9:36 |
| 2 | 19:08 | 9:31 |
| 3 | 28:35 | 9:27 |
| 4 | 37:58 | 9:22 |
| 5 | 47:16 | 9:18 |
| 6 | 56:30 | 9:13 |
| 7 | 1:05:39 | 9:09 |
| 8 | 1:14:44 | 9:04 |
| 9 | 1:23:44 | 9:00 |
| 10 | 1:32:40 | 8:55 |
| 11 | 1:41:31 | 8:51 |
| 12 | 1:50:17 | 8:46 |
| 13 | 1:58:59 | 8:42 |
| 13.1 | 2:00:00 | 1:00 |
There is no exact science when it comes to negative splits.
The best you can do is to practice negative splitting during your training and employ all that you’ve learned during the race itself.
Related: What is a good 5k time? Average 5k time by age and gender
More tips for running negative splits
#1 Check the course
Your pacing strategy can quickly be overturned by the course terrain.
If the course has lots of hills and complicated terrain, it will be difficult to pick up your pace in the second half of the race.
So if you’re serious about achieving your next PB, pick a course that is relatively flat without any twists and turns.
#2 Check the weather
Like the terrain, the weather can scupper your chances of achieving your next PB, so it’s important to check the weather forecast before running.
Heat, cold, wind and rain can make it difficult to run a negative split.
#3 Start at the front
It’s all too easy to get caught up in the crowd when you cross the start line which can interfere with your race strategy.
Make sure you find a spot at the front so you can break away from the crowd when the race starts.
#4 Stay relaxed
It’s understandable if you feel some pre-race nerves and jitters, especially if you’ve put in months of training.
Try and stay relaxed and believe in what you have practiced during training.
Related: How many miles is a 10k? Average 10k times by age and gender
3 negative split workouts to try
If you’re new to negative splits and want to give them a go during training, then here are some negative split workouts to try.
These are designed to get you used to working with negative splits so you can then start doing more structured workouts.
All of these workouts use the 1 to 10 rate of perceived effort (RPE) scale, starting at 4 and gradually increasing to 8.
| Rating | Perceived effort level |
| 0 | No exertion, rest |
| 1 | Very light |
| 2-3 | Light |
| 4-5 | Moderate, comfortably hard |
| 6-7 | High, vigorous |
| 8-9 | Very hard |
| 10 | Maximum effort, highest possible |
#1 Interval workout
Interval training is a great way to improve your endurance, stamina and speed as a runner.
They work by getting you to run a series of repetitions (intervals) of the same distance, but the idea is that you run slightly faster during each repetition.
The first three repetitions should feel comfortably hard – say between 4 to 6 out of 10 on the effort scale.
The last three repetitions should feel challenging to very hard – say between 6 to 8 out of 10 on the effort scale.
- Warm up
- Run 1 x 600m – 4 out of 10 RPE
- Rest for 2 minutes
- Run 1 x 600m – 4 out of 10 RPE
- Rest for 2 minutes
- Run 1 x 600m – 6 out of 10 RPE
- Rest for 2 minutes
- Run 1 x 600m – 6 out of 10 RPE
- Rest for 2 minutes
- Run 1 x 600m – 8 out of 10 RPE
- Rest for 2 minutes
- Run 1 x 600m – 8 out of 10 RPE
- Cool down
Remember to walk or light jog back to the start line after each repetition – this is your recovery time.
#2 Progression workout
The goal of a progression workout is to gradually increase your pace throughout the run.
They are great because they get your body and mind used to running the latter parts of the run faster.
- Warm up
- 5 minutes – 4 out of 10 RPE
- 5 minutes – 6 out of 10 RPE
- 5 minutes – 8 out of 10 RPE
- Cool down
#3 Tempo workout
Sandwiching a tempo run into the middle of your regular run teaches you to alternate between slower and faster paces during a run.
- Warm up
- 20 minute easy run – 4 out of 10 RPE
- 10 minute tempo run – 6 to 8 out of 10 RPE
- 20 minute easy run – 4 out of 10 RPE
- Cool down
Related: 7 of the best running workouts to build endurance, strength and speed
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