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Negative splits for the marathon - theory or reality? (Read 930 times)

J2R


    Last Sunday I ran the Frankfurt Marathon, and was happy to get the pacing just right, or so I thought - very slight negative splits, second half 25 seconds faster than the first. When I looked at the times of people who came in in a time close to me, I was struck by the fact that nearly everybody else had positive splits. OK, I thought, but surely the elites will be showing negative splits. But no - of the top 50 runners, only 3 had negative splits! And by elites, I do mean elites - the race was won in 2:06:08 by world record holder Patrick Makau, and even he had positive splits, albeit only very slight.

     

    Given that this was a flat course, on a day without strong headwinds, there seems no physical reason why the second half should have been slower than the first. This makes me wonder whether this whole idea of the optimal way of running a marathon, with negative splits, might be some kind of 'in an ideal world' thing, and not in fact what happens in reality even for the elites? Of course, there is the theoretical possibility that the midway point was slightly mismeasured, but that seems unlikely - after all, it's Germany we're talking about hereSmile.

     

    So how often are negative splits in fact run in a marathon? Or are they only in the theory books normally?

      Elites tend to have rather even pacing compared with mere mortals. Negative or positive splits for elites typically mean a minute either way - most of us would call that even pacing for all practical purposes.

       

      People get hung up about negative splits, but in practice I think you just want to aim for even pacing. You really don't know how the last few miles are going to go until you get there if you are running close to the best pace you're capable of on the day...

       

      Note however that marathon world records are often set off slight negative splits.

        Most of the fastest men's and women's marathon times ever run have been done with very slightly negative splits, so I think its safe to assume this is ideal.  The fact that most normal people have violent positive splits in marathons or that even elites come up short of their goals more often than not should not be confused with what's optimal.

         

        Makau's Frankfurt splits were almost dead nuts even: 1:02:55 / 1:03:14 and that's on a day he described his legs as "not very good today."

         

        It's really hard to get the pacing just right in a marathon, even for the best runners. That doesn't mean you shouldn't try.

         

        My own marathon PR was run with a 1 second negative split--basically dead even. I don't think it's a coincidence that in 13 tries at the distance the one time that I didn't have at least a 2 minute positive split, was also my fastest race ever at the distance.

        Runners run.

          Also, elites are typically racing, not running for time, so that often throws the whole negative splits question out.  Most of the rest of us who are just contending for 763rd place are probably running for a time goal.  In this case, I have had a lot of experience with banking time and bonking hard.   A negative splits strategy for me leaves a little more in the tank and usually ends in a better result.  No myth for this guy, although in the interest of full disclosure my PR race was a slight positive split.  It was the closest thing to an "optimal" marathon I have ever run, though.  Even so, I had a slight bonk at mile 24 and lost 30 sec/mile the last two miles.

          - Joe

          all running goals are under review by the executive committee.

          jimmyb


            I remember checking this out one year with the Boston results; that year the best had negative splits. I just checked out another year and they had positive splits. My guess is that the number one factor is the pace set from the outset and they then race each other accordingly. The winner this year at Frankfurt set a blistering pace, and it looks like the others followed suit and slowed considerably in the second half due to the fast start. The winner had what I would call an even pace. I consider 23 seconds between halves to be even. It's very difficult to get two halves exactly even. The existing research on this that I've seen in the past is that even pace is best if you can do it.

            Log    PRs

              Sometimes I think we put the cart before the horse in this debate. I suspect that in many cases, the PRs and WRs come because the runner had a good day and was able to accelerate or hold the pace after an ambitious first half. So, the negative split is the result of a good day, rather than the cause of the good day, if that makes any sense.

               

              Of course the thing about racing is that you really can't know if you will have a good day and be able to hold your best possible effort. The whole art is getting yourself in position to run well in case you do without going out so hard that you totally blow up. And then being fit enough and tough enough not to bleed too much time if you don't have a great day.

               

              For inexperienced runners who are still on the fat end of the improvement curve, it's best to err on the side of caution when "putting yourself into position for your best possible race." For more experienced and highly trained runners looking to chip away, this can become a pretty delicate game.


              I'm back!

                I just did a quick check -- 9 of my 10 fastest marathons were negative splits. The one that wasn't was a crash and burn. The top two (and only sub 3s) were at Boston, not typically a negative-split course (except, often, for the elites).
                MrH


                  As others have commented, elites are questionable as a measuring stick because they are often racing. It's not a time trial.

                   

                  The success of negative or even splits over a long race doesn't seem like a great mystery. It means you had enough in the tank to maintain a consistent pace  and good form even when you were getting extremely fatigued. If your form breaks down over the last miles they will be slow enough that any early gains from running a little faster will be lost, and then some.

                  The process is the goal.

                  Men heap together the mistakes of their lives, and create a monster they call Destiny.

                  DoppleBock


                    I would consider anything within 1 minute faster or slower between 1st half and 2nd a fairly even paced race if the course is pretty consistent.

                     

                     

                    I always try and run a pace I believe I can maintain the whole way ~ This usually means the last 10k is really a painful struggle both in the legs and in breathing - I never seem to be able to get enough oxygen as I am pushing to keep the pace up in the last 10k.

                     

                    Only in my 1st marathon did I hit 10k to go and was able to pick it up significantly.  2:28 1st 20 (7:24) and 41:48 last 10k (6:45) - That was caused by not understanding how to run a marathon.

                     

                    Just because someone runs evenly or negative does not answer if they ran near max potential ~ Maybe that person left 2-3 or more minutes on the course because they did not push hard enough?  It is the question I always ask myself post race ... how much time did you leave on the course.  Either from pacing too fast or too slow the 1st part or any other poor race execution. 

                    http://a-big-horse.blogspot.com/ 

                    2013 Goals ~ Mar < 3:00, 5M < 29, 10k < 35  

                     

                      Sometimes I think we put the cart before the horse in this debate. I suspect that in many cases, the PRs and WRs come because the runner had a good day and was able to accelerate or hold the pace after an ambitious first half. So, the negative split is the result of a good day, rather than the cause of the good day, if that makes any sense.

                       

                      I agree with the second sentence (and the parts of the post that I didn't quote for that matter) but how is any of that putting the cart before the horse?

                       

                      In races we've spent months training for it only makes sense to pace ourselves based on what we think we could do on a good day, knowing full well it doesn't always (or even usually) work out. To me neither one is the cart or the horse--to run your best possible marathon you need to run the right pace AND you need to be having a good day.

                      Runners run.

                      DoppleBock


                        PS - My PR was bad pacing

                         

                        Mile #1 5:57

                        1st 10k 38:47

                        Half 1:22:53

                        2nd half 1:23:05

                        last 10k 38:50

                         

                        Looks golden on the results page- But reality is I ran way too fast the 1st 10k, held on and tried to recover until mile # 20 and then gave every once of effort I had the last 10k - I was in a daze and out of it for 2 hours post race.

                         

                        6.2 38:47 = 6:15 pace

                        6.2-13.1 = 6.9 miles in 44.1 minutes = 6:24 pace

                        13.1 - 20 = 6.9 in 44.25 minutes = 6:25 pace

                        38:50 = 6:16 pace

                         

                        Maybe it still does not look that bad, but 12.4 miles of the race were at 6:15 and 13.8 miles continous were at 6:25 ~ Reality I ran hard to 8 miles and  really dogged it until mile #11 (I remember a mile @ 6:50) ... I was all over the place in mile splits.

                        http://a-big-horse.blogspot.com/ 

                        2013 Goals ~ Mar < 3:00, 5M < 29, 10k < 35  

                         

                           

                           

                          I always try and run a pace I believe I can maintain the whole way ~ This usually means the last 10k is really a painful struggle both in the legs and in breathing - I never seem to be able to get enough oxygen as I am pushing to keep the pace up in the last 10k.

                           

                           

                           

                          Interesting.  I don't think I've ever run a marathon where my breathing was ever a struggle.  For me it is ALWAYS a sudden (large) increase in effort to maintain what I had been running easily for 20 miles.  On good days I can maintain and sometimes even increase a little but even then it's not a breathing thing.  I always wonder if that's the difference between runners like myself (kinda mediocre but OK) and better runners - the ability to push oneself (ignore the discomfort) into the realm you describe where even breathing is labored.

                           

                          To the original post - yeah, I think for us time-trialers it's best to go for your best pace possible that you can hold for 20-22 miles and then hold it for 26.2 no matter what.  On a flat course I'd guess that'd be even splits.

                          DoppleBock


                            Jeff and MikeyMike - I agree that break throughs come from often come form being more aggressive than we think we can be, or stupid stubbornis and it turns out it is our day or we find out we can do more than we thought we could.

                             

                            But results often show that a very low percentage actually have "Their Day" or get rewarded for agressiveness ... Making it so much more sweet when it happens.

                             

                            It is miserable to painfully struggle in at a much slower pace after being aggressive.  But every once in a while, I like to be reminded about how that feels.  It seems to have less of a point when you are far from PR shape.

                            http://a-big-horse.blogspot.com/ 

                            2013 Goals ~ Mar < 3:00, 5M < 29, 10k < 35  

                             

                              Yup, it's a crap shoot. Do you want to minimize your chances for major suffering, or would you rather take the 1 in 10 shot at a breakthrough knowing that there's a 90% chance you miss and suffer like an animal over the last few miles?

                               

                              I've always swung for the fences, which is why my ratio of positive splits to even/negative is 12 to 1. It's not a game for the faint of heart.

                              Runners run.

                              DoppleBock


                                When I am forcing myself to maintain pace - Although my legs are lead, it is my ability to process oxygen that limits my effort.  I spend the time focussed purely on having my posture and body in the optimal position to breath deeply as possible.  The time is spent in a sereal dizzy state, lungs hurting, head floating with an occassional moan.  The damn legs don't want to, but they have no choice ... but I cannot force my body to absorb oxygen faster. 

                                 

                                But, I feel the same in the last mile of a 5k or last 2 miles of a 5 mile or 10k.  The marathon is the supreme challenge to keep it up for 4-6 miles.  But somehow after you have invested 2+ hours, it is mentally easier for me than the 5k or 10k to go and stay there.

                                 

                                Interesting.  I don't think I've ever run a marathon where my breathing was ever a struggle.  For me it is ALWAYS a sudden (large) increase in effort to maintain what I had been running easily for 20 miles.  On good days I can maintain and sometimes even increase a little but even then it's not a breathing thing.  I always wonder if that's the difference between runners like myself (kinda mediocre but OK) and better runners - the ability to push oneself (ignore the discomfort) into the realm you describe where even breathing is labored.

                                 

                                To the original post - yeah, I think for us time-trialers it's best to go for your best pace possible that you can hold for 20-22 miles and then hold it for 26.2 no matter what.  On a flat course I'd guess that'd be even splits.

                                http://a-big-horse.blogspot.com/ 

                                2013 Goals ~ Mar < 3:00, 5M < 29, 10k < 35  

                                 

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