Negative splits .... are they the magic elixir everyone makes out??

Im thinking of trying it in a HM on sunday, but in the back of my mind Im worried that I'll start out slow, then continue slow and end up with .... you guessed it, a slow time.

Somehow it seems better to have 'time in the bank' by pushing out a bit at the start and then seeing where you are at the halfway point.

Any thoughts? or have I bored you already?

Err no. Distance run is either start as you mean to finish or get to half way and if ther'es anyhing extra in the tank because you're having a good day, pick it up. If you've trained for 4 hr mara no poiny doing 1.50 1st half as you'll clow in the second and if you take 2.10 you won't have enough in the tank to pull back. The negative split isn't a huge time difference and very few actually achieve it.

At the highest level, where you are racing against the other runners of similar ability I can understand the logic as you have a bit in reserve to overtake the person in front etc.

When your main competition is yourself, i.e. setting a PB etc, then a even split is easier to achieve and likely to give you the same result.

I usually manage a negative split, if only by a little.

I start out at my target pace and see how I go.  If I'm feeling good as the race progresses, then I pick up the pace a bit.

All my pbs have been negative splits.

Love this - A great read.

"“No matter what pace you start at, you will slow eventually, so start at a fast pace which will give you momentum.”

http://www.ultralegends.com/the-tipton-100-miles/

every time i have run a pb it has been on  a negative split, except for 5k

Yes / No / Maybe / depends / haven't a clue. 

If running was a bank account, you'd have a very short period of interest free loan, then the charges start racking up. If you go overdrawn at the start you'll make the bankers rich. And they'll charge you for the letter. 

How not to pace a half marathon and still get a pb

1 - 5:31.71
2 - 5:51.46 - 11:23.17
3 - 5:56.82 - 17:19.99
4 - 5:58.11 - 23:18.10
5 - 6:01.18 - 29:19.28 (5 mile pb)
6 - 5:56.34 - 35:15.62
7 - 6:06.73 - 41:22.35
8 - 6:14.23 - 47:36.58
9 - 6:11.15  - 53:47.73
10- 6:12.65 - 1:00:00.38 (10 mile pb)
11- 6:21.44 - 1:06:21.82
12- 6:30.54 - 1:12:52.36
13- 6:22:46 - 1:19:14.82
13.2- 00:36.05 - 1:19:50.87

Ian M wrote (see)

Love this - A great read.

"“No matter what pace you start at, you will slow eventually, so start at a fast pace which will give you momentum.”

http://www.ultralegends.com/the-tipton-100-miles/

Proper.  Mental.

even splits are the ideal (for half-mara up to mara distances)
the idea is to ramp up the effort (not pace) as you go along
so your final mile run "eyeballs out" takes the same time as your first mile run "smooth and relaxed"
this all depends on whether your target pace was "correct" in the first place though, and you only find that out after you either positive-split (unrealistically fast target) or negative-split (overly conservative target)

picking the right target pace is a whole other thread...

"Proper!"

"Mental!"

I don't pay that much attention to splits, only going so far as to check my time halfway through a 10k and then again when I cross the line. I find I ALWAYS run the second half faster than the first, but it's not a conscious strategy, I hink it's more that I relax when I know I'm on the homeward leg. If I checked my splits every kilometre I'd get really hung up on it, so I just don't do it.

I thought the perceived wisdom was that you started slowly and gradually accelerated as you warmed up, so don't most people have at least some negative splits?

thespare wrote (see)

 

I thought the perceived wisdom was that you started slowly and gradually accelerated as you warmed up, so don't most people have at least some negative splits?

If you're properly trained for the distance, you'll have warmed up properly before the start of the race, so that you can be up to race speed soon after the gun goes, after which time the best strategy is even splits as far as I'm concerned.  As Daz suggests this actually involves gradually ramping up the effort level through the race so that your level of discomfort slowly builds, but still bearable whist maintaining pace.

In practise, a lot of people end up running negative splits simply because life's too short to beast yourself silly to the point of exhaustion for every single race, and easing yourself in and finishing strong is a more pleasant experience, even if it doesn't yield the absolute fastest time possible.