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Discussion Starter #1
What is the best approach to train yourself into doing negative splits?

Most of my runs currently start off quicker and slow down.

A typical run of say 20km, would average 5:00/km over the first 10km, then slow down to 5:30/km for the next 5km and perhaps finish off with 5:45/km for the final 5km.


The reason I slow down is purely down to getting tired and physically not being able to go any faster!

The only way I can see to go faster in the second half is to force myself to run at a slower pace in the first half, but I don't think I'm at the point where I could just reverse the above times, fatigue still sets in.

If I say started off at 5:45/km for the first 5km, then sped up to 5:30/km for the next 5km, I don't think I'm able to then speed up to 5:00/km. I might be able to speed up a little at that point to maybe 5:20/km but the final 5km would probably end up slower again around 5:30/km???

So overall the run would end up slower.

I've read so much about negative splits being better, that I want to try and do it, but what is the best way to approach it?

Is it to just do the above, watching the clock and trying to be faster in the second half, not worrying about the overall time?

Perhaps mentally thinking of the first part as more of a warm up than part of the run?


Having said all that - I've just looked through my running app for my best ever run of that distance that had anything like a negative split. It was whilst running with a friend, I ran the first 9km with them but then left them at that point to meet up at the end. With that one I averaged 5:33 for the first 10km, but then managed an average of 5:15/km for the second 10km.

I don't think I could repeat that though - I think there must be some coincidence of perfect conditions given for that! It is also a one off!

So how slow should I aim for in the first half?
 

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Hi,
I think you have the answer in your question. Try starting with 5.45. See how it goes. If you speak racing - when they say negative split and racing competitively difference in splits is 2-3%, not 20%, so it is closer to flat pacing.

My opinion is - if you slow down almost one minute per km because of fatigue - your tempo is too fast or distance too long for your. Cut it a bit.
Normally you shall never ever feel tired half way into your run (considering it is not a 5k race when you can struggle through it).

BTW, what heart rate you start and finish? Are you doing easy run (or what are you trying to do)?

Ps
And to answer your concerns - starting too fast makes you tired too early and leads to inefficient running. You shall avoid that if possible.
My recent half (with no training for that, not a single threshold session this year at that time) I started 30-40 secs slower then final km (and 15-20 slower then average pace). Was totally fresh at half distance, could speed up considerably at finish. And still better time then pr. Normally that split range is waaay too big (did that mainly because didn't know my condition)

PPS In all my easy runs I speed up towards the end of the run, with no concise effort, just naturally. Trying to fight that with no success
 

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Pps, if you speak racing (which I missed probably) id start with 5.30, making 5.15 at half distance and 5.00 at half of the remaining half
 

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Discussion Starter #4
Thanks for this,

I don't currently monitor heart rate.

I gave it a bit of a go this morning. Not looking for a dramatic change but just holding back a little at the beginning then getting into it as I went. I did 15km of moderately hilly running.

My 5km times were as follows:

27:35
26:31
26:09

I was fairly happy with that, and it gave an average pace of 5:21/km which I was fairly happy with for a comfortable training run. I felt good at the end and could have gone further. The final 5km averaged out to 5:14/km.
 

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I don't know about "best" but one way is to use the feelrace MARCO method. I have used this for a lot of marathons and it has helped me iron out the late-race fade and run a negative split half nearly always, including at Boston, which is a bit infamous for late hills. It relies on heart-rate monitoring. The basic principle is to run against a gradually increasing HR target. There is also guidance for a half here too. On anything shorter I tend to run a flatter HR curve-target but following the same principle.
 

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I don't know about "best" but one way is to use the feelrace MARCO method. I have used this for a lot of marathons and it has helped me iron out the late-race fade and run a negative split half nearly always, including at Boston, which is a bit infamous for late hills. It relies on heart-rate monitoring. The basic principle is to run against a gradually increasing HR target. There is also guidance for a half here too. On anything shorter I tend to run a flatter HR curve-target but following the same principle.
Failed for me (I assume my target was a bit optimistic and I was also too optimistic on how I manage hills on the route) - worked well until 35km then I just lost tempo.
Maybe it was a nutrition issue as well.
But I still beleive in that (probably next one will do with a bit bigger split then it recommends).
 

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I'm a master at the progression run lol, favourite type of run. Just practice with the odd 6-10 miler where first miles is very easy then play a game of trying to take 10-15s off each mile, it gets real fun by the end! Pacing is so important in races but is so often overlooked or ignored, myself included.
 

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Discussion Starter #8 (Edited)
OK - I've started to look a little at HR. I had a read of the link above (MARCO). I dug out my chest strap and my forerunner 405CX and went out for a long run.

Not my usual run for the following reasons:

It was hot,
It was a bit further than a normal Sunday morning run,
I decided to use my camelbak to carry 2L of water to keep me hydrated.
I was running solo, which is fairly rare.

I've checked my resting heart rate and it seems to be about 48bpm but I was trying to do it first thing in the morning, but I have to wake up, then put the chest strap on, then have another 10 minutes or so in bed before reaching over and picking the watch up and changing it to the right setting.

At the start of the run after a couple of stretches etc. My heart rate was around 70bpm. As I ran it seemed to be around 145bpm for a good while, increasing slightly when going up an incline and dropping again after. As I got further in my 'normal' HR began to increase, by about 16km it was more like 160bpm on the flat.

I just ran at a comfortable pace, I didn't go for a specific goal. I ended up running a half marathon (distance wise) - not a fast one (just over 2 hours) but hot and hilly.

Endomondo says my average over the entire run was 155bpm with a max of 172bpm.

Hopefully this will work and show a graph from Endomondo below:



I've no idea what much of this means, or why it is like it is!

In terms of negative split, there wasn't much difference between the KM splits today. My fastest km was the 15th one, which just happened to coincide with it being the only stretch on a main road without any pavement and I wanted to get past it quicker!

Otherwise it was:
1 5:35
2 5:41
3 5:59
4 5:42
5 5:40
6 6:10
7 5:53
8 5:35
9 6:24
10 6:17
11 6:19
12 6:24
13 5:57
14 5:40
15 5:26
16 5:57
17 5:53
18 5:45
19 5:54
20 6:11
21 6:05
 

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Discussion Starter #9 (Edited)
Today, I did a bit of interval training. It was just 5km. Interval distance was random based on a landmark ahead. Sprint to Landmark then recover until HR was below 145.





Average HR was 148bpm
Max HR was 177bpm


Does it show anything else?

It was good fun but my legs ache now!

I've excluded altitude from the graph above because Endomondo went a bit weird and put a 200m climb in the middle. This run had a gentle climb for the first 1km, then as flat as possible for 3km then back down the 1km back to the start. Approx 30m of climb in total.

Is there anything from this I should be watching for improvement? Am I looking for faster recovery times? etc.

*EDIT*
The two sudden drops in HR at roughly 1.5km and 3.5km are where I stopped at traffic lights - auto pause was on so my HR had a few extra seconds to lower.
 

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If you are doing intervals, turn off auto pause and auto lap. Press the lap button at the START and END of your effort and don't stop the watch in between. You can stop the watch during warm up and cool down if you want, though.

That will get you the effort and the recovery as separate laps and allow you to look at those separately. Looking at an entire run is kind of useless, and the recovery is just as important as the effort.

However, you can't tell anything from a single session. You need multiple sessions over time so you can track your progress. It also helps to make a note of the weather because abnormal weather will affect your efforts.
 
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