Should you run a negative split?

London Marathon Mass

I’ve been contemplating how to run the London Marathon in 2 weeks time. In my research, it’s come up a few times that I should run a negative split.

  • A negative split is running the second half of a race faster than the first
  • A positive split is the opposite – a faster first half of a race faster than the second
  • An even split is run both halves at the same pace.

My current plan for the London Marathon is to do 9 min/miles and come in under 4 hours. If I’m honest, I’m probably going to go off a little quicker, bank some minutes and then if I slow down, I’ve hopefully got something in the bag, so to say. Therefore, run a positive split.

However, everything I’ve read and my own (sensible) thoughts on it are – take it easy at the start and then maintain or increase the pace. Therefore, run a negative split.

Negative splits are the holy grail of distance running, especially with elites. It is thought to be the best way to achieve a quick time. There are evidence and examples either way, but does it work for the non-elites?

So, what to do? I think it really comes down to is – which kind of risk taker are you?

Both plans have their own risks.

Negative split – Do you trust yourself that you will have the pace in the second half and maintain it for a distance you’ve only done a few times or maybe never?

Positive split – Do you trust yourself that you will not go off too fast in the first half and not hit the wall in the second?

For any regular readers, you may know I’m definitely a purveyor of positive splits, and there are many similar tales of me crashing in the latter miles. This comes from my first marathon, London in 2008, when I when out controlled, finished really strong and felt I left a lot of time out on the course.

Whilst this practice can work over 5km, 10km and you can survive a half, it could be suicide for a marathon. Let’s do a pros and cons list-

Pros of a negative split

  • It increases your chances of running a consistent and strong race.
  • It converses your glycogen energy stores and there is less chance of hitting the wall.
  • The mental toughness of going slow at the start maybe easier than the mental toughness of “hanging on” at the end.
  • Feeling strong and passing people towards the end of a race can be a great boost.
  • How did you want to feel during the race? To you want to enjoy it and feel strong or be in the pain cave, swearing you’ll never run again?
  • It’s possible to practice so you can test it out on training runs.
  • I like the maxim – The guy or girl who slows down the least. Wins.

Cons of a negative split (doing a positive split)

  • Running a negative split is hard to do. Only 1-8% of runners manage to do it.
  • If you keep this in mind. 90% of the people around you will do a positive split. Therefore lots of people go off fast. There is a huge temptation to try to keep up with the crowd.
  • If it backfires, there’s not much you can do about it. Your fuels stores are used up and your muscles suffer a lot of damage. Your race implodes.
  • A great line I heard – “Do not try to bank time, the bank charges interest”.
  • If you do blow up, how slow will you actually go? Is the banked time going to be enough?

How to run a negative split

I may not be your greatest exponent of this, but most of this is a reminder for me as much as it is for you.

Start slow – The first few miles might feel really slow, particularly after your taper, but there’s a long way to go. Run the first 3 miles as slow as you dare, keeping your heart rate low and breathing easy.

Keep it conversational – Speak to the people around you. Make some new friends. I much prefer running with people and talking takes your mind off it for a few mins. Meeting people and chatting to people will be the bits of the marathon you remember.

Let them go – If you are running with someone (by their side or behind them) and they start to edge away, let them go and stick to your pace and plan.

Break it up – Break up the race into sections and concentrate on only the current section. 6 mile or 10 km or good sections you will commonly know.

Trust yourself – Trust your body and your training that you will be able to speed up during the race. If you conserve your energy during the early part of the race, it will be there for you at the end.

Focus – Focus on staying strong. It’s gonna hurt, whatever you do. Be mentally prepared for this and be ready to dig in in the latter miles.

Know your pace times – Write your paces on your arm or there are normally pace wristbands available at the London Marathon expo.

Be adaptable – not everything will go to plan. An unplanned toilet stop could make you lose your nerve, but stay with it, don’t change the plan drastically.

Be prepared and ready to go – See my preparation tips post here. It’s one of my most popular posts and I’m quite proud of it! Don’t let 17-18 weeks of training go down the train, for a stupid decision in the days beforehand. Be primed and ready. Don’t leave anything to chance.

Trust the process – You’ll be going into your marathon or race feeling better than you have for all those long runs. You’ll have fresh legs, be carbo-loaded, hydrated and rested.

Good luck!

Kingston Spring Raceday Recap/Review – 31st March 2019

Kingston Spring Raceday Start I’ve run the Kingston Breakfast Run as this run was once called once before back in 2010, before my last London Marathon. It has been a mainstay for many years for spring marathon runners as it offers a 16-mile race, 4 weeks before the London Marathon and 2 weeks prior to Brighton. Continue reading “Kingston Spring Raceday Recap/Review – 31st March 2019”

Marathon Training – Weeks 1 to 13


I’ve been meaning to post this for some time. Now there’s only 4 weeks until the London Marathon. I’m following the VLM intermediate plan. It’s the most structured plan I have followed for some time. When I say structured, what I probably mean is, it’s one I’ve followed most rigidly. Continue reading “Marathon Training – Weeks 1 to 13”

Podcasts – Tidy Up Your Life Admin


This is going to be a series of posts about tidying up the general clutter in digital life. It’s very much the “One day” category of decluttering. “One day I will look/listen/read this thing” but you never do and it just builds up and up! This second post is about podcasts. Continue reading “Podcasts – Tidy Up Your Life Admin”

The Big Half Race Review and Recap – 10th March 2019


This is the second year of the half marathon organised by the organisers of Virgin Money London Marathon, the Prudential RideLondon festival of cycling and Swim Serpentine.

The entry was via ballot and is purposely very timely for the upcoming London Marathon. The general entry fee was £39.00 (£35.00 for members of a British Athletics affiliated running club). Entry fee for runners from the four boroughs the run passes through was £30.

The Build Up

It was a 6 am alarm. Luckily I set two alarms as I fell asleep after the first. Continue reading “The Big Half Race Review and Recap – 10th March 2019”

The Awesome Running Playlist – Track 24

Track 24 – For What You Dream Of – Bedrock (1993)

Dropping back to an all-out dance classic this week. Off one of the best dance complication albums ever and part of the classic Trainspotting soundtrack, is the British electronic music duo (John Digweed and Nick Muir) with their dance floor stomper from the early 90s. Continue reading “The Awesome Running Playlist – Track 24”

Ronhill Mens Infinity Cargo Stretch Running Shorts – Review

Ronhill Cargo ShortsI recently raved about the On Hybrid Running Shorts. I thought I had found salvation – carrying my phone and other bits whilst running. Whilst I solved my problem, I was still not quite happy. The inner shorts were a bit short for me. I always wear tight/compression shorts that come to just above my knee and then loose shorts over the top. The On inner shorts come halfway down my thigh. Also, although I bought an extra-large in the On Hybrids, the inner short is still a bit too small to get over my ass.

I then came across the Ronhill Men’s Infinity Cargo Stretch Running Shorts. Continue reading “Ronhill Mens Infinity Cargo Stretch Running Shorts – Review”

Email subscriptions – Tidy Up Your Life Admin

Email subscriptions

This is going to be a series of posts about tidying up the general clutter in digital life. It’s very much the “One day” category of decluttering. “One day I will look/listen/read this thing” but you never do and it just builds up and up! The first post is about email subscriptions. Continue reading “Email subscriptions – Tidy Up Your Life Admin”