Negative Splits

I'm interested in people's thoughts on negative splits, particularly on the run.

Lets say you're aiming for a 4 hour marathon - are you really more likely to hit that target if you run the first half in 2:05 as opposed to 1:55?

Isn't there a real danger of leaving yourself too much to do in the 2nd half of the race - which you have to balance with the other danger of blowing up?

So far in most races I've finished slower than I've started but hit a lot of goals this way so I'm less than convinced about the need for negative splits.. but would welcome the collective real-world experience of all you forumites!


  • I've never run a negative split in a marathon. I always slow down. But it's definitely not a good idea to go out too fast for the first half. You lose more time like that.
  • Run the first half at target pace, then run the second half faster.
  • is this for an IM Marathon..??

    I've not met many people who negative split it. 
    Go out 'easy/steady' for the first couple of laps - conserve as there's a long way to go. 
    The third lap will be hard - man up and don't slow down.
    Lap 4 out - yip yip. every pace is closer to the finish - just keep running
    Lap 4 heading home - pick it up, and up - ignore the legs / brain and just keep going.image

    Its a definite negative split in effort but won't be in pace / time.

  • D0MD0M ✭✭✭

    I run negative splits in most of my races by running hard but steady/controlled and then pushing myself into oxygen debt for the last 20-25% of the race.  Negative splits in a marathon, I would argue this applies more to the elite to 3hr runners. For the 4hr plus runners, the marathon is a different race. It is more an endurance test. Think of it like this:- ask an elite marathon runner to run as far as he can in 4 hours, different approach needed now.  That`s what a fun runner has to contend with. My best marathon was 3hr 28 off 1hr 43, 1hr 45 splits. If going for sub 4hr, I would recommend trying to stay bang on a 3hr 59 pace and try and hold it.

  • I have negative split both of mine... (Outlaw)

    Takes me 9 hours to get into my grooveimage
  • Ha - your steady is too steady then.....

    Or have you just got a good sense of pacing.....?

    Seriously, if you are really going for it then you have to go on the upper end of steady and then really crank it up in the second half. it will hurt and you will suffer but you just have to ignore the pain - apparently. seeing rosie shifting it an hour ahead in wales - he was really burying himself. i obviously have a much lower pain threshold as i could never get above steady.... And i always had something lwft for a sprint finish. i should have left ot all out on the course....
  • Nah - I say it jokingly but there's reasons for both:

    1st was a beginners error - the first half I run/walked thinking I'd got nothing left, but was just breaking up my momentum. Eventually I started running all but the aid stations and picked up the pace.

    2nd was because I am still stupid - dived back into transition to grab rain jacket (only for weather to go fine) so lost 2/3 mins there in the first half, and then had to stop at the med tent to get some ibuprofen for my ankle too, so that was a good 4/5 mins as I had to fill out a form!! image

  • DoM - I think I'm with you.. I think I need to settle on a realistic target based on something I can hold (I'm in the 3:30+ bracket for stand-alone marathon). As for IM, same approach, although In my one IM to date I did try that approach and it did work - until the 1st aid station. Gross over estimation of ability and conditioning looking back image

  • The problem with that approach is that you've no real idea of the pace you could hold for the whole thing until you're a little way into the run, and by then it's probably too late. It depends a lot on how the bike went, for example.
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