ReSUltS - The Reality Slowdown UltraStu Marathon Formula

Hi,

(To those of you that are a little bit short of time I have copied the link to the useful webpage that this blogpost is explaining immediately below.  The remainder of this blogpost helps to explain some rationale behind the webpage slowdown formula, but one can go straight to the webapage, and hopefully the data it provides will be reasonably clear.  If not come back to this blog post.)

How fast should I run at the start of the marathon?  This is where the following webpage is really useful.  http://rsusmf2.appspot.com/   Please note that this slowdown formula has been updated form the version one which I introduced on UltraStu April last year within the post A Helpful Marathon Pacing Calculator The two improvements are that version two of the slowdown formula takes into account the gender of the runner, as this seems to have a significant effect on the percentage slowdown for the same finishing time.  I have also removed those runners that in simple terms 'blow up', and therefore have a very high percentage slowdown. Further description on the formula are detailed below.

Back in May 2013 I wrote two blog posts on the fallacy of the negative split for road marathon running, which created 'a bit of a stir'.  Which was further 'stirred up' with two other posts during April last year:  A Helpful Marathon Pacing Calculator and Road Marathon Pacing - The Positive Split Pacing Strategy - My Final Comment   At the time I stated that those posts would be my final comment on the topic, however, with marathon season 'kicking off' with the Brighton and Worcester marathons this weekend, and then Manchester, London and others during the following two weeks, I felt that one final blogpost on the topic could be so beneficial to the thousands of runners who will be running a road marathon during the next few weeks.

By now with the bulk of the physical training completed, the focus of the preparation should be on the non-physical training.  By that I mean predominantly goal setting and visualisations.  In terms of goal setting many runners will have a target marathon finish time that they would like to achieve, so this can form one of your goals, i.e. a destination goal.  This is useful as having this target finish time goal can help you in providing a counter argument to the many messages you will get during the later stages of the marathon, strongly encouraging you to slow down.  In addition to a destination goal, it is also useful to establish some journey goals for you to evaluate along the way, just to check that you are on track, and running well.  These journey goals may be related to your emotions during the run.  Are you enjoying the experience, are you 'staying within the present moment', are your race focused. are you running at the ideal intensity, right on that threshold?  Yes, it is useful to establish some journey goals, and then include what you want to be achieving whilst running the event within your visualisations leading up to race day.  Anyway, enough about goal setting, lets get back to marathon pacing.

As mentioned above, many runners will have a target finish time that they would like to achieve.  The issue is, what pacing strategy is best to increase the likelihood of achieving ones target finish time.  Now as ideal as the even paced marathon pacing strategy sounds, and with the argument typically being that most of the World records are set with an even paced, or a negative split paced strategy, in reality around 93 - 95 percent of all marathon runners who finish the marathon quicker than four and a half hours run a positive split.  That is that they slow down during the second half of the marathon, so their second half marathon time from 13 - 26 miles, is slower than their first half marathon time from 0 - 13 miles.

Now, this post isn't going to repeat my discussions on why I think this positive paced strategy is the ideal strategy.  You can go to my two posts from May 2013 if you want to read my rationale for my stand: The Negative Split - The Realisation that An Accepted Running Concept is Actually Flawed!    and The Negative Split Fallacy - Part 2 - The Explanation!   No this post is amount the reality of actually running the marathon, not opinions, theories and speculation!

So, the situation is that around 93 - 95 percent of marathon runners finishing a road marathon quicker than four and a half hours slow down during the second half of the marathon.  At last year's London Marathon within the non-elite field.  I think it is best to disregard what the elite marathon runners do, as their characteristics are quite different to the non-elite, 2:30 - 4:30 marathon runner.  Interestingly though, at last year's London Marathon only two elite men (2/18 = 11.1%) and two elite women (2/14 = 14.3%) achieved a negative split, so not that dissimilar to the 10.0 and 16.0 percent of non-elite runners in the quickest time band (see below for time band explanation).  Mo Farah also achieved a positive split of 3.30%, which is also not that dissimilar from the 3.88% for the quickest non-elite mens time band.)

     Sorry, I got distracted there!  So, the situation is that around 93 - 95 percent of marathon runners finishing a road marathon quicker than four and a half hours slow down during the second half of the marathon.  As I was going to say, at last years London Marathon 93.3% of finishers quicker than 4:18 ran a positive split.  The overall number of women runners from the first 4000 women finishers (4:18:15) that negative or even split their half marathon times totalled 292, which corresponds to a percentage of 7.3%. The overall number of men runners from the first 12000 men finishers (4:18:10) that negative or even split their half marathon times totalled 782, which corresponds to a percentage of 6.5%, which is a slightly lower percentage than for women.

So for 93 - 95 percent of marathon runners the big question is "How much time should I expect to slow down during the second half of the marathon"?  The vast majority of marathon runners aiming for a target finish time need to have an idea of the amount of slowing down that is most likely to occur, as they need to take this amount of slowing down into consideration, so even with this slowing down, which I consider IS A REALITY, NOT, I WILL REPEAT NOT AN INDICATION OF POOR RUNNING OR POOR PACING,  so that they will still achieve their target finish time.

Now I am NOT advocating for road marathons to start as fast as you can, to gain as much time as possible ahead of the even paced schedule.  No, this would be unwise.  This would be as foolish as trying to run at a constant pace for 26 miles.  No, what I am suggesting is to look at the statistics on how much slowing down occurs within the marathon, and I have used the data from 4000 women runners, and 12000 men runners from the 2014 London Marathon as the database.  And to base the calculation of how much slowdown one can expect to occur, on the AVERAGE of what happened for these sixteen thousand runners.  So quite a good sample size!

In order for the resulting percentage slowdown formula to not be influenced by those runners that absolutely 'blew up', I removed the ‘mega slowdown’ runner, those that slowed down more than two standard deviations from the mean slowdown percentage.

Those of you that are particularly observant may have noticed for the quicker runners the percentage of runners that even split or negative split the marathon was greater the quicker the finish time, with the quickest time bands being 10.0% (men) and 16.0% (women).  Yes, there does appear to be a gender difference.  The percentage slowing down, (which is calculated as the time one slows during the second half marathon, divided by the first half marathon time, multiplied by 100), is therefore slightly less for the quicker finishers.  therefore to accommodate theses characteristics of the 16000 finishers, different slowdown percentage were established for different finish time bands and for men and women runners.  The following table displays the AVERAGE percentage slowdown values for each time band, for men and women runners.

Now having these percentages in a table is interesting, but what does it actually mean for the runner.  How fast should I run at the start of the marathon?  This is where the following webpage is really useful.  http://rsusmf2.appspot.com/ Please note that this slowdown formula has been updated form the version one which I introduced on UltraStu April last year within the post A Helpful Marathon Pacing Calculator As stated above the two improvements are that version two of the slowdown formula takes into account the gender of the runner, as this seems to have a significant effect on the percentage slowdown for the same finishing time.  I have also removed those runners that in simple terms 'blow up', and therefore have a very high percentage slowdown. Further description on the formula follows.  Opps, I also forgot the third improvement for version 2, in that the slowing down now doesn't start until the 16th mile, rather than the 14th mile.  I think this is more likely to be representative of what actually occurs.  As long as the runners have a realistic target finish time, maintaining a constant pace for 15 miles should be a problem.  It is during the last 11 miles when the effects of the previous miles run on the roads starts to have an impact and make the maintaining of the same constant pace a lot more difficult, hence the slowing down.

As an aside, if I recall at the time last year there was some confusion expressed regarding my perhaps wrong assumption that the accepted view at the time was that an even paced strategy pace was the standard approach, which would result in most runners not achieving their target finish time if adopting this approach.  Now I think that probably more people realise that the even paced pacing strategy doesn't work, so hopefully this year there will be less confusion.

Unfortunately the webpage calculations aren't exactly correct, due to either some mystery formatting error or simply the effect of rounding error, which we now think is the likely cause of the error.  We, actually, in reality it is good friend Tim, who is the brains behind the webpage, who has been working hard on looking to solve the problem.  Anyway it is nearly working perfect.

Just to quickly summarise.  The way the webpage ReSUltS -  The Reality Slowdown UltraStu Marathon Formula works is that you select male or female, then enter your target finish time, then click calculate.  I mentioned above that the webpage isn't working exactly right, but If you look at the minute mile pace the formula produces, the half way and 5mile, 10 mile and 15mile split times are all correct.  But when the percentage slowdown linear increase occurs at mile 16, there is a big slowdown for mile 17 and then back to a linear increase in minute mile pace until the finish.  It appears that this big slowdown at mile 17 is where the slight error occurs.  In terms of the summary table on the right the pace column is for the last mile of that 5 mile split, NOT the average pace for the last 5 miles. 

However, although the webpage isn’t exactly working, the key information, e.g. the percentage slowing down, which allows you to calculate your half marathon split time is correct.  Also the idea that one should be able to run at a consistent pace for every mile up to 15 miles is also correct.  The last 11 miles around 93 - 95% of marathon runners slow down, how they slowdown will be quite varied, but a gradual linear increase every mile from 16 miles onwards seems a reasonable guess, which the slowdown formula adopts.  Remember slowing down after 15 miles doesn’t mean that you are running poorly, or that you did the first 15 miles too fast.  Slowing down is reality. The webpage does produce a different minute mile pace for each mile from 16 miles through to the finish, however, I would recommend that you simply use the minute mile pace generated for the first 15 miles, which takes into account the average slowdown for that time band, and then from mile 16 onwards, simply run by feel.  If feeling great then reduce the rate at which you slow down.  If not feeling so great, then allow a slightly greater rate of slowing down and hope that the 'difficult patch' will pass, and that you may be able to get back 'on track' a few miles later.


Hopefully the above explanation of this ReSUltS -  The Reality Slowdown UltraStu Marathon Formula webpage makes some sense, and for those of you are able to take on the fact that 93 - 95% of marathon runners slow down during the second half of a road marathon, I hope that you find this webpage useful.  To those of you that aren't aiming for a target finish time, or are aiming for an even paced strategy, well then this webpage probably isn't relevant for you, so apologies if you have read this blogpost down to here!

To all of you running a road marathon during the next few weeks, I wish you all the best.

I will sign off with a few relevant quotes which may help during those 'challenging' moments between 16 and 26 miles.

"The way we perform is the result of the way we see ourselves.  To alter our performance we need to alter or change ourselves and it is that changing that's difficult."  Gary Elliot, New Zealand Coach to awesome NZ marathon runner Alison Roe (1983)

“A large amount of what we achieve is governed by our mental state and how we see ourselves. (It is) a lot about opening the mind to what might be possible when we throw away the self imposed limitations of our mind.” Tom Williams from MarathonTalk (2011)

“Remaining positive really is one of the most precious faculties for any athlete.  That, and an ability to stay focused and disciplined.  Develop a mind bank of positive images and thoughts – family, friends, previous successes, favourite places, a big plate of chips.  You need to build it up as you would any collection, but soon you will have a range of thoughts to flick through when next your body and soul are screaming out for relief”.Chrissie Wellington, Four times World Ironman champion,  from her book titled "A Life Without Limits".

 
Enjoy the journey,

Stuart

 

The Negative Split Fallacy - Part 2 - The Explanation!

Hi,

Yes, following on from lasts week's post where I used the data from this year's London Marathon to show that running a negative split is not an indication of a good performance, tonight I will hopefully provide an explanation into why the negative split doesn't work for non-elite runners.

In response to last week's post, and to previous pacing posts, I have received a number of comments.  Thanks for the comments, it is nice to know that people are reading these blogs, and the blog is achieving its aim, of getting people to question / evaluate their ideas on running, in this case on pacing.  Some of the comments I totally agree with, others have got me questioning why I believe my view that differs is more likely not to be wrong.

I guess the key issue, which many people have difficulty dealing with, is that if the negative split seems to work for the very very best in the World. i.e. the World recorder holders, then surely it should work for everyone.  Below are two comments received.

"As I pointed out in my recent post about the folly of positive split, elite marathoners achieve their best performances by running negative or very even splits. This evidence screams out the small negative or even spits are best, but you just dismiss that somehow Elite's and non Elite's are somehow different because they train differently, and that somehow "magically" positive split becomes best." Robert.

and

"No offence to hundreds of thousands of runners, but quite frankly I don't care that 95% of them run positive splits. The real question should be could they have run a faster time if they would have run more even splits? And again, who cares if it was even a PR - could that PR have been a better PR?  I think this topic is very hard scientifically to prove physiologically...but I do think a big stack of correlated data is useful. If you look at the data and nearly all world records at all distances come from even to slightly negative splits, that has to mean something. Random middle of the pack people running positive splits to me only solidifies the point." Brett.

How elite marathon runners manage to achieve a World record on a negative split, I don't know.  However, what I do know is that for non elite runners, attempting to achieve an even split or a negative split in a marathon is not the right approach.  I have provided the statistics to show this, e.g. 121 out of the first 122 finishers of the non-elite field at the 2013 London Marathon ran a positive split.  But now is the time to explain why for non-elite runners, the positive split is the best approach.

Firstly, the argument for the even split strategy as provided within a comment left:

"Mathematically and energetically, even splits are best. If you do a negative split, then you will have been losing time in the 1st half of the race. A positive split and you'll be losing time in the 2nd. Fact. Additionally, any variation in pace will generally result in poorer running economy. Of course, things are never as simple as that and tactics, course and environmental conditions will all have an affect on what is the ideal pace" Andy.

Yes, on the face of it, if we look solely at the energetics of running, keeping a constant physiological intensity does appear to be the correct approach.  The only problem is, that for non-elite marathon runners a constant running pace DOES NOT result in a constant physiological intensity.  This is where the confusion lies!  Now you will note that I again have used the term for non-elite runners.  This is because I have been unable to find published material within the scientific literature that has data on elite marathon runners, in terms of how much the physiological intensity increases throughout the duration of the race, whilst running at the same pace.  If anyone has got some literature on this aspect, please e-mail me the author names/title or provide a link within a comment.

So in paraphrasing/plagiarising Brett above:
"No offence to the elite runners, but quite frankly I don't care that the very very best of them run negative splits. The real question should be could I run a faster time if I would have not tried to run even splits? And again, who cares what the elite do if it was even a World Record - I am not an elite runner, I do not have the some time / resources / 'talent' etc,  what do I need to do regarding pacing so that my marathon time could have been a better PR?"


So what do I mean by a constant running pace DOES NOT result in a constant physiological intensity?  Lets look at some data.

First I will look at the following study: How Do Humans Control Physiological Strain during Strenuous Endurance Exercise? Jonathan Esteve-Lanao, Alejandro Lucia1, Jos J. deKoning, Carl Foster. This study monitored the running performance of 211 male middle and long distance runners with an average age of 32, and of various abilities. All trained for and entered competitions with the intent of achieving their best possible performances. Although not elite performers, all were serious competitors and some were successful in regional competitions.  The average time for the marathon was 3 hours 01 minutes.  The graph below displays how as the marathon race progresses, there is a continuous increase in heart rate, whilst at the same time there is a decline in running speed, starting at around the 20km mark, (ignoring the downhill section between 25-30km).

One explanation for increases in heart rate during endurance events is that it is a result of cardiovascular drift, and this is thought (not totally understood) to be due to a combination of dehydration, increased body temperature and increased sympathetic nervous system activity (e.g. adrenaline release).  Whether the percentage increase in heart rate attributable to cardiovascular drift truly represents the same percentage increase in physiological intensity is debatable.  Although the heart rate is increasing, the cardiac output (this being the amount of blood being pumped out of the heart every minute) may not be increasing, as the reason the heart rate has increased, is because the stroke volume (the amount of blood being ejected each heart beat) may have decreased.  I'm trying to stay away from the actual causes of fatigue tonight, so won't comment on the relationship between the heart rate and the rating of perceived exertion, and how this relates to fatigue, as I am trying to solely focus on the physiology.  But typically a rise is heart rate during a race means that the athlete is 'working harder'.

So if these 211 marathon runners wanted to maintain an even pace throughout the marathon, to avoid the decline in their running speed in the second half of the race, they would require an even more significant increase in heart rate during the second half.  Already the heart rate has increased from around 85% of HRmax until half way, up to around 90% of HRmax at the end of the race, so most likely an increase in HR of around 8 - 9 beats per minute.  To maintain an even pace for the second half of the race would require an even greater increase in heart rate, so as you can see, running an even pace DOES NOT result in a constant physiological intensity.

Just to get around the issue of whether the increase in heart rate does actually represent an increased physiological demand, if one wants to define physiological intensity as being represented by cardiac output rather than heart rate.  Then looking at how cardiac output increases during a race would be useful.  A recent study from 2012 did exactly this!  Using some new technology they managed to record cardiac output of 14 middle-aged runners running in a real marathon race, with an average finish time of 3 hours and 50 minutes (so a slower group of runners than the previous study).. The study was titled: Cardiac Output and Performance during a Marathon Race in Middle-Aged Recreational Runners. V´eronique L. Billat, H´el`ene Petot, Morgan Landrain, RenaudMeilland, Jean Pierre Koralsztein, and LaurenceMille-Hamard.

Again, as the marathon statistics from the London Marathon showed, with 96% of runners positive splitting a marathon race, there was a continuous decline in running pace as shown in the graph below.

The graph also shows how even though pace has significantly decreased, the cardiac output has stayed pretty constant, maybe a slight increase.  Again it is clearly obvious that if the 14 runners wanted to maintain a constant pace, i.e. run an even split, then there would need to be quite a significant rise in cardiac output.  The authors of the paper have illustrated this in the graph below, where they have expressed heart rate, stroke volume and cardiac output in relation to per metre run, so in essence in relation to running at a constant speed.

The continuous increase in all three physiological variables is apparent, therefore demonstrating that to run at an even pace DOES NOT represent an even physiological load, it represents an increased load.  The actual values per meter run reported were significantly greater for kilometres 36–40 in comparison to kilometres km 8–12, with increases of 21 ± 16% for Heart Rate Speed (Figure 4(a)), 25 ± 17% for Stroke Volume Speed (Figure 4(b)), and 26 ± 22% for Cardiac Output Speed (Figure 4(c)).  This data therefore shows how the one argument (apart from the World record argument) this being the so called optimal even constant pace strategy does not represent an optimal even constant  physiological load!

I appreciate that these 14 runners have an average finish time of 3 hours 50 minutes, so some of these runners were achieving slower finish times than what many runners aim to achieve, so some people may question the 'value' of this data.  In addition, the finish times had a standard deviation of 45 minutes, so a large range of finish times.   The fastest time was 2:57, and the slowest 5:10, hence why there are large standard deviation bars on the above Figure 4.  Taking into account this large variation in finish times, the researchers looked for any significant relationships between the physiological data and the marathon finish time.  The following graph displays one of the key relationships found.  This being that there was quite a strong relationship (r = −0.65, P < 0.01) between the upward drift in the Cardiac Output /speed ratio and finishing time.

The key is; what causes this upward drift in the Cardiac Output throughout the race?  If one is able to reduce this drift, which for these 14 runners was quite substantial, averaging an increase of 26 ± 22%, then there is likely to be an improved performance.  As illustrated in the above graph, the amount of drift does appear to influence marathon performance.  It is likely that as a runner gets physiologically 'fitter', one benefit is that there is a reduction in the level of upward drift in cardiac output.  And maybe the reason that the very best of the elite, i.e. the World record holders are able to achieve a World record on an even paced, or a slight negative split strategy, is that they are so physiologically fit that they do not have the same upward drift in Cardiac Output as the non-elite runner. Again, if anyone has go any HR / running pace data on elite athletes during a marathon please share it.

When comparing between the elite and the non-elite, one must also remember that the duration of the race for the elite (with a finish time of a little over 2 hours) is on average around only half the finish time of the average runner.  Therefore the average runner is running for double the amount of time!  As the upward drift in cardiac output is continuous over time, then the longer the time of the event, the greater the drift will be, and hence in terms of the optimal physiological energetics, the further away the runner must then be from trying to achieve an even race running pace strategy.

Now lets go back to the message I was trying to get across in my last post, based on the data from 25,000 marathon finishers (< 5 hours) at the 2013 London Marathon, although I only looked in detail at the the first 11,000 finishers (< 4 hours).  Still a pretty big sample size.  The table below lists the percentage average percentage slowdown for six finishing time bands.

So if we look at a 3:50 marathon finisher, the data from London Marathon 2013 indicates that on average they slowdown during the second half of the race by 9.9%.  The percentage increase in the cardiac output speed ratio in the above study was on average 26%.  They shouldn't necessarily be the same, i.e. the same percentage drift upwards of cardiac output being equal to the same percentage slowing down in running pace, however, one would expect the values to not be this different.  Why the difference between these two percentages then?  One is due to the way the percentages are calculated, where I calculated the percentage slowdown as the difference between the first 13 miles average pace, and the second 13 miles average pace.  Whereas the study calculated the difference between the fastest 4km split (8-12 km) and the slowest 4 km split (36-40km).

One must also look at the 14 subjects used in the study (middle-aged, male, recreational marathon runners all of whom were national-level short-distance triathletes or international level cyclists).  It is therefore likely that due to not being marathon runners, their legs may not have been 'conditioned' to the pounding they get whilst running a marathon, as opposed to cycling.  It is therefore likely that they may have experienced increased drift in cardiac output due to extensive damage and fatigue within the leg muscles.  I am only speculating here, but leg muscle fatigue has been shown to have a large influence on marathon running performance.  And with these 14 subjects being national level or international level, one would expect that aerobically they were very fit, so this excessive muscle fatigue could be a reason why the average finish time was only 3:50.

Anyway, regardless of the specifics of these 14 subjects, I hope that I have been able to illustrate above that in order to run at a constant even pace throughout a marathon, requires a progressive increase in physiological load, and therefore is contradictory to the even split physiological energetic argument often presented as to why the even split pacing strategy is optimal.

As I have just mentioned the issue of muscle fatigue, which has been shown is a key aspect with regards to marathon running performance, I'll expand of this aspect a wee it.  A recent 2013 study (Running Pace Decrease during a Marathon Is Positively Related to Blood Markers of Muscle Damage. Juan Del Coso et. al.) that investigated muscle damage in 40 amateur runners with an average finish time of 3 hours 12 minutes, found that their leg muscle power, tested immediately after the marathon, had decreased by 17%.  Interestingly the average percentage decrease in running pace was 16%.  So clearly with marathon running inflicting muscle damage, with the muscle becoming fatigue, there is obviously going to be an increase in physiological load as the marathon progresses, and hence the upward drift in cardiac output.

Again, a bit of speculation, but perhaps due to the extremely high levels of training that the elite marathon runners are able to perform, due to being full time athletes, then perhaps their legs are more 'conditioned' and therefore they do not 'suffer' the same amount of muscle fatigue, and so do not encounter the same upward drift in cardiac output.  Hence why it is not wise for the non-elite runner to try to 'mimic' what the elite runners achieve.  Hence why trying to run an even split / negative split for the non-elite runner is simply foolish!

In terms of how foolish.  What consequence will it have?  Well lets say for a 3 hour 50 minute runner. with a percentage slowdown of 9:9%, which is the average for a runner of this finishing time, then this runner on average would slow down 11 minutes and 23 seconds during the second half of the marathon.  So if they went out to go through half way in 1:55, they would miss their 3:50 target by on average a little over 11 minutes.  If they had just gone out that little bit faster, rather than running totally comfortable for the first half of the race, they would only need to have reached half way in 1:49:35, less than 5 and a half minutes quicker, and they would achieve their target finish time of 3:50.  By going out that little bit quicker, they are therefore able to slowdown their pace during the second half of the race, in order to keep the physiological intensity more constant , which is argued as the optimal strategy one should adopt.

Well, this post again has ended up being a bit longer than anticipated.  However, hopefully I have helped explain why the even spit pacing strategy is not wise for non-elite runners.  The fact that 96% of marathon runners positive split isn't because 96% of marathon runners are getting it wrong.  It is because the concept of the negative split / even paced strategy is WRONG!

I am suggesting that due to the on average 5.1 - 9.9% slowing down of pace during the second half of the race, for a sub 4 hour marathon time.  In order to counteract this, in reality this rather small amount of slowing down, the runner only requires a slight increase in running pace for the first half.  By acknowledging this percentage slowdown, which takes into account the physiological responses that actually occur during a marathon, rather than some non-evidence based ideal of an even paced strategy, then there will be an increase in marathon runners achieving their goals, which surely must be a good thing!

I will sign off tonight again with the quote from Tom from Marathon Talk:

“My money's still on the even / negative split but I'd be delighted to be proved wrong. My quote for the day... I'd rather know I was wrong than think I was right ;)" Tom Williams, 2011.

Hopefully after tonight's post, there is sufficient proof for Tom to stop encouraging the thousands of listeners to Marathon Talk to try to achieve an even split, or at worse a negative split.

All the best as you plan your pacing strategy for your next race,

Stuart

PS I promise that this will be my last post on road marathon running.  I will get back to trail running blog posts, so apologies to those trail runners out there that aren't interested in road marthons, and the emphasis on mile split times and finishing times.

Yes, UltraStu will return to trail running, and just as a taster, I received an e-mail from the Cotswold Outdoor Store asking if I could promote their newly released trail running video titled "Why I Run: A short trail running film".  So to get back into trail running mode, here is the LINK to their video.  Take a look as I 'm sure it will remind you, after all of this road running talk (not that you probably need reminding), of the joy of running on the trails.

A Tiny Bit More on Pacing, and Trail Running Sussex Develops

Hi,

Tonight's post will be just a short post.  Firstly, a little bit more on race pacing, and then an announcement of an exciting development for Trail Running Sussex.

Last Sunday morning I had a great time watching the BBC TV coverage of the London Marathon, whilst at the same time, watching on the London Marathon website the live progress of five runners I were tracking.  The London Marathon website was excellent.  It would automatically update every 5 kilometres and at halfway, with the runners last 5km (1.1km) running pace, and a predicted finish time.  It would also predict (based on the runner's pace to date) where they were on the course every ten seconds or so.  So a great feature that added to the enjoyment of watching the elite races.

The women's elite race had a pretty small field, and straight away it became clear that the elite women runners weren't interested in the pace that the two pacemakers were setting.  So, in terms of elite women standards, a reasonably large bunch 'dawdled to the 20 km mark, passed through halfway in a time of 71:49, and then they started racing.  The 5km split time decreased from 17:11 for 15 - 20km, to 16:01 for the 20 - 25km split.  The race was won, with a negative split of 3:23, running 68:26, for a finish time of 2:20:15.  The second placed women, also achieved a negative split of 2:06, but all of the other 15 elite women finishers positive split the race, with the largest positive split of 13:17 by the current Olympic champion, although she did get knocked down by a wheelchair racer!

The elite men's race was quite different with the men's field keeping in contact with the pacemakers who were running at sub world record pace.  They actually ran the first 5km in a time of 14:23, which is quite amazing being a marathon pace resulting in the time of 2:01:23!  No wonder that was the fastest 5km split of the race, and pretty well every subsequent 5km split got progressively slower.  Now this was a demonstration of taking my motto of "Run as fast as you can, while you can!" to the extreme!!!  So with the men's elite field going unbelievably quick, there was actually still a lead bunch of 7 runners at halfway, reached in 61:34, still under world record pace, with the reigning Olympic champion just 14 seconds back. 

All of these eight runners filled the first eight finish places, all slowing down significantly so none of them, in fact, none of the entire men's elite field achieved a negative split.  The winner ran a positive split of 2:52, and the largest positive split was 5:31 (8th place) and the smallest positive split was 0:19 (9th place).

Around two years ago I analysed the London Marathon 2011 results to help understand the 'stupidity' of trying to run a negative split in a marathon.  (Check out the Pacing article.) So I didn't feel that there was a need to repeat this analysis, so I thought I would look at some results data in a different way, and this time just looking at the top end of the field.

I therefore downloaded the top 500 finish times and their half marathon split times from the massed start field.  With the belief that running a negative split is detrimental to ones performance, I thought it would then be simple to produce a scatter diagram plotting the amount of the positive/negative split against finishing place, to illustrate this performance inhibiting relationship, with those who run a negative split finishing in lower places. 

First I ranked the 500 runners in terms of the positive split, with a rank of 1 is the runner that slows down the most, and the rank of 500 is the runner that speeds up the most during the second half of the race.  Well take a look at this scatter diagram below, with a coefficient of determination of 0.00001.  This data is pretty well as close as as you could ever get to illustrating that there is absolutely no relationship at all between the amount of the positive/negative split and finishing pace.

I then instead of looking at the relationship between the positive/negative ranking and finish place, I looked at the relationship between the actual positive/negative time and the finish time.  Again there appears to be pretty well no relationship! Why?

I then had to really think, why no relationship?  Surely those that run a negative split, have only achieved this because they have run the first half of the race so slowly.  It then jumped out at me.  Yes, those that negative split perform poorly, but they just simply move lower down the finishing place list.  Throughout the field people will finish with a certain time due to many factors, so there is a massive spread of finish times.  Within this spread of finish times, some runners will perform well in relation to their fitness, ability, belief, whatever else, and hence move further up the field, finish faster.  Whereas some runners will perform poorly, i.e. finish slower.  But the good or poor performances will not stand out within the results, they simply move upwards or downwards amongst the finish results.  Hence the zero relationship.

However, if we look at the very top end of the field, those who run a poor performance, which I believe is due to running a negative split, will move down the results list, and those who run a good performance, those who I believe who run a positive split, i.e. start out fast and then slow during the second half of the race, will move up the result list.  And being at the top end of the field, simply moving up or down into the next portion of the results list can't occur, so this true relationship wont then be lost!

So what do the results fro the London Marathon 2013 show us.  As already described, all 19 elite men finishers ran a positive split, and 15 out of the 17 elite women finishers also ran a positive split.  But what the elite do may not translate to the non elite.  So looking at the top level club runners from the London Marathon, as expected, those that run a good performance move up the result list, and those that run a poor performance move down the results list.  For the massed start field, out of the first 118 finishers, from a finish time of 2:17:10 through to 2:37:30, so the best non-elite performers, ONLY ONE runner achieved a negative split.  All of the other 117 runners ran positive splits.  I don't think I need to discuss this topic again.  The idea that running a negative split is a sign of a good running performance has now been totally 'blown out of the water'.  End of story!

Well that first subject of tonight's post wasn't quite as brief as I thought!

My second topic tonight is related to the running venture I am involved with, Trail Running Sussex.  You may recall that I mentioned last month that Trail Running Sussex has recently been established and provides guided runs and trail running camps within Sussex.  The first running camp has an ultra trail running focus, and takes place from Friday 21st June through to Sunday 23rd June, based at the National Trust Slindon Estate, near Arundel. Well, Trail Running Sussex has just set up a relationship with the newly established online running store The Ultra Runner Shop.  So, in association with The Ultra Runner Shop, all trail running camp participants, and those that attend a guided trail running weekend break, will receive a 15% discount on all running kit purchased from The Ultra Runner Store.

I am really excited with this development, as The Ultra Runner Store, which has been set up by ultra runner Tony Holland and his partner Helen, not only stocks top quality kit, but they are also raising money for and awareness of the Downs Syndrome Association.  So if you have a spare moment, check out their website at the following address http://www.ultra-runner.com/ and if you need any running kit, see what they have and give them a go.

Time to sign off.  I shouldn't really be having any late nights at the moment, with my first key race of the year taking place this Saturday, being the 53 mile Highland Fling.  To those of you racing the Fling, I wish you all the best.  I'll see you on the start line at 6:00am, and whatever you do, don't try to attempt to run a negative split!

I will sign off with some appropriate words that were within a comment left on my blog by Tom back in September 2011 following my UTMB DNF:

"Training is just that, (the ability to tune in), and it is during this period you need to build your confidence and physical ability. This is the time to build mental strength and grow and in that respect I agree 100% with your model.  Once this is achieved you have the physical and mental tools to perform on race day but you also need to have these set to auto so that you can trust without thought. I see it like the auto neuro response that makes your heart beat - you don't give it thought you just trust it will happen.  The secret, in my view, is on race day to be able to forget everything (trust the heart will beat) but tuning into the environment that nature throws your way and flow with it and thus enjoy it (vital).

I believe we can all 'mentally horde' without realising it and maybe all this preparation is taking away from what matters. Maybe we can forget to trust and not separate training from the joy of racing.

Training = build the physical off the mental.
Race Day = Trust and enjoy."

See you on the trails,

Stuart

Pacing - Still a Mystery!

Hi,

Should be a short post tonight, mainly responding to the many comments that have been left during the last week.

Firstly thanks to the many comments left, both the feedback from last weekend's TORQ day and in response to my blog post on hydration, nutrition and pacing.  With regards to the blog post comments, to summarise the comments, it seemed to be agree my hydration observations, pretty well agree with my nutrition/carbohydrate views, but really mixed reaction to my pacing ideas" Hence tonight's post title "Pacing Still a Mystery!.

Just before I move onto the pacing issue, I just want to mention one more bit of evidence from the scientific literature regarding carbohydrate and fatigue.  I have just come across an interesting 2013 article titled "Running Pace Decrease during a Marathon Is Positively Related to Blood Markers of Muscle Damage" which is a free available journal at this link.  I will come back to this article later in the post but one key finding that is reported is as follows:

During exercise, glucose supply for the active skeletal muscle comes from glycogen stores in the muscle and liver. However, if the exercise bout is of long duration (> 1 hour), muscle and liver glycogen stores deplete [17] and blood borne glucose has to be used to provide energy, threatening blood glucose homeostasis [38]. It has been found that hypoglycemia attenuates the activation of the CNS and hence produces reduced exercise performance [39]. For this reason, the reduction in blood glucose concentration has been proposed as a source of muscle fatigue during the marathon [40]. When blood glucose is maintained by ingesting carbohydrates during exercise, muscle force and CNS activation are better preserved [39]. Interestingly, participants in this investigation increased the blood glucose concentration by 0.6 + 0.6 mmol per litre, from pre-to-post exercise (Table 2), as has been previously found in other athletes participating in endurance events [41]. Although we did not record carbohydrate ingestion during the race, previous studies have found that marathoners have appropriate rates of carbohydrate intake [42]. According to our data, blood glucose concentration was well maintained during a marathon in a warm environment, reducing the influence of hypoglycemia as a source of fatigue during this race [43].

So therefore confirming what I have read previously in other journal articles, in that now carbohydrate gels / bars are commonly used DURING marathons, the issue of hypoglycemia (low blood sugar) and glycogen depletion now seldom occurs.  Therefore fatigue during marathons is due to other fatigues, which I believe is when Race Focus Energy is depleted (see my Race Focus Energy / Fatigue Post).  

Back to pacing, as mentioned above their was mixed reaction to my most recent blog post, where I totally 'slated' the concept of the negative split.  One reader commented that they had "never heard anyone say that their goal for a race was to run a negative split".  Well Richard obviously doesn't listen to MarathonTalk (unlike I believe around 15,000 other runners per week!)  If he did, he would then know how this negative split is totally 'raved' about!  There were many comments, including Tom from MarathonTalk, back in December 2011 when I first blogged about the fallacy of the negative split, who present evidence that even pace works for them, or for other people they know including elite runners.  But then others state that a fast start worked well for them.  So it appears simply from this small sample size that no one approach appears superior to the other, and it really gets down to trial and error, and what works for you.  

Although, that does appear to be the 'safe' conclusion, I am not really convinced, so I will continue to try to find evidence to dispel the negative split / even pace myth!  So before I finish tonight's post, a few more comments.   The key focus of the article mentioned above was related to muscle damage, and there finding tends to reinforce what I believe is one of the main cause of fatigue during marathons and ultra events, yes muscle damage.  Their key finding was "Running pace decline during a marathon was positively related with muscle breakdown blood markers.".  Therefore those runners with the most muscle damage, slowed down the most.  However, the mechanism in which the muscle damage slows the runner down I feel is not entirely directly related to the muscle damage, as the muscles are still able to generate more than enough force to run, but indirectly.  Yes, the fatigue will be partly related to the reduced efficiency of the muscles due to the damage, so it will take more energy to produce the same amount of force, so an increase in intensity for the same running pace.  But more important is that the discomfort resulting from the damaged muscles will require increased focus, increased mental effort to deal with this discomfort.  This will therefore increase the rate at which you consume 'race focus energy' (RFE), so you will become mentally tired as your RFE stores deplete, and will therefore be unable to maintain that mental drive, that push, focus to keep running at the hard/demanding pace you were able to manage earlier.  Hence you will slow down. 

 I particularly like one of the comments left during the week, from Chris:

I think with the ultra pacing side of things it's really about finding the correct balance for you as an individual. If you are always going to slow to a certain speed then it makes sense to leg it whilst you can, but the ability to get data with a real true control group is impossible to draw a true conclusion; e.g., what if you had run 10 seconds per mile slower on average for the first 50, what would you have done in the second 50? would you have been more than 10 seconds per mile faster to give you a faster overall time? You'll never know with absolute certainty.  For me this leads to two conclusions (1) you have to experiment to find your right personal blend, preferably on the same course and conditions to give you the best control possible - does running faster to start with make you hit the slow down point significantly earlier? essentially experience counts for a lot and you have to be prepared to fail to get your personal data; (2) assess through experience what happens to you in the latter stages - mental state, concentration on maintaining speed and pushing on (rather than mentally drifting) if prone to mental drifting then you probably adopt a default "knackered pace" so the focus is then on getting as far as possible before you hit this and training to up your knackered pace.

Particularly the importance of "assess through experience what happens to you in the latter stages - mental state, concentration on maintaining speed and pushing on".  Yes, it is really important to reflect on your previous races and try to identify what caused you to slow down.  I did this extensively at the end of 2012, and identified that it was the muscle damage that caused me to slow down, hence my training this year is focused on trying to reduce the muscle damage I experience during the second half of ultra trail races.  Please not that I don't attribute my slowing down in races being due to starting fast, as Sp Lane states "I know it doesn't make much difference if I start slow or fast, I'm still going to die later on.  Hence, it's my best interest to get as far as I can as a short a time as possible."  Exactly, I couldn't have said it better!  

Anyway, I could go on and on, I feel I need more than personal opinion.  So time to get my analytical brain in action, and gather some data, and last weeks Anglo Celtic Plate 100km road race in Perth, Scotland, provided the data I needed.  I took quite a big interest in last Sunday's race as I have raced quite a few of the guys running.  Thanks to John Kynaston's tweets, I was able to keep up to date as the race progressed.  From John's tweets it looked like it was a two man race between running friend Dan Docherty from Ireland, but lives in Berkshire, and England's Thomas Payn, who I didn't know.  Dan's running has really come on in the last two years, so I was surprised when he wasn't leading during the first few hours, with Payn out in front.  John would tweet the leader board every hour or so, so I could see the race positions, but no time gaps.  Then shortly after the 5 hour mark, Dan takes the lead and goes on to win in a very respectable time of 7:05:23.  Yes, that magical 6:59 still eludes Dan!  

Back to some evidence regarding pacing strategy.  Well, the 100 km race consisted of 42 laps, each 2.38km in length, and each lap time was available on the web.  So I downloaded these and got to work!   First I looked only at Dan and Tom's splits.  I was also interested in how far ahead Tom got, and when did Dan hit the lead.  The following to graphs display this data.    

  So you can see both athletes slow down, but Tom's decline in pace was much more dramatic!  Tom started out faster, got up to a 5 min 48 sec lead, and then Dan pulled this back, and got in front on lap 32 or 42.   Next I decided to look at all 31 finishers to see how their pace decline over the 42 laps.    

  Two runners had some really slow laps, and two others had laps slower than 14 minute mile pace, so I deleted these four runners, and carried out further analysis on the 27 other runners, who never got slower than 13:45 min mile pace.   I think it is reasonably clear to see that the trend for the 31 runners is that they slow down during the second half of the race.  I then plotted the average , fastest and slowest min mile rate for each lap, so the average slow down would be clearer to see.    

  This graph illustrates some interesting points regarding slowing down. Firstly it confirms that the average pace slows down a reasonable amount from around half way.  But was is really interesting is that the slowest average lap was lap 37 with an average pace of 9:19, and then speeds up on each of the following last five laps, so the last lap average pace is 8:44.  Now this data clearly illustrates just how rubbish the old physiological model of fatigue was.  I challenge any physiologist to explain what has happened during the last part of the race physiologically!  Hence why a new model of fatigue was required, and I haven't seen any better than my Race Focus Energy (RFE) model.  Yes, a bit of bias there, but if any psycho-physiologist out there are aware of any better models, then please let me know.  

Why is the slowest lap six laps out from the finish.  I propose that the main reason is that as the race draws closer to the end, five laps is less that 12 km, so around 7 miles, the subconscious no longer needs to maintain it's reserve tank of RFE.  Up to this point it keeps stored safely away an emergency supply of RFE because of the unknown, the doubt of what could happen, a safety supply to deal with experiencing the un-encountered,  But with only 7 miles to go, the subconcious is well aware that 7 miles is easily manageable so therefore makes this emergency supply of RFE available, and hence the running pace can increase as there is more Race Focus Energy.  In addition, the negativity from the unknown, the doubt of possibly DNFing, struggling etc. is reduced during this late stage of the race, and this reduction in doubt / fear / negativity swings the RPE - RFE arrow downwards, so able to run quicker for the same rating of perceived exertion (RPE).  

Next for the 27 runners I wanted to get an even more clearer indication of the degree of the slowing down during the race.  To achieve this I decide to break the race into six sections of 7 laps each, so a little over 10 miles per section.  I then calculated the average decline in pace during the 2nd to 6yth section, i.e. each 10 mile split from 10 to 61 miles, in relation to the time split for the first 10 miles.  Here is the graph below.    

  Yes, some interesting percentage slow down data here, with the pace nearly being maintained until halfway, and then slowing down in relation to the first ten mile split, by 9, 17 and 19% for splits 30 - 40, 40 - 50, 50 - 61 miles respectivelyy.  

Lastly I wanted to see what the relationship was between the percentage that the runners slowed down in terms of their first ten mile split and their final ten mile split, and their finishing time.  As it is commonly believed, as stated by Christof "Slowing down has a very profound effect on finishing time, so a near flat pace theoretically produces the fastest result."  If this myth actually true.  Or as I belief, the only reason anyone actually achieves a negative split, i/r/ doesn't slow down during the race, is that they have run the first section so very slow, that the time they have lost during this section is never regained!  What does the data show us.  In order to try to relate directly to elite ultra runners, I decided to delete from my 27 runners, any that did not break 10 hours, so four more runners were deleted (sorry if you were one of these four runners!), and the slowest finishing time from my sample of now 23 'elite' runners is now 9 hours 37 minutes.    

  The graph above clearly suggests that Christof's statement is incorrect (sorry Christof, but you are most welcome to reply and counter my evidence), with a correlation of only r = 0,23.  And if one looks at the coefficient of determination (R squared), which is thought to indicate the amount of commonality between the two variables, it would suggest that only five percent of the factors that contribute to ones finishing time can be attributed to the percentage one slows down during the race.   So five percent is a very low percentage, barely above zero, but the correlation is a positive correlation, which indicates that the more you slow down during the race, the slower your finishing time.  Which is rather disappointing for me in providing evidence that "Run as fast as you can, while you can" is the best way to go.  I would have need a negative relationship between the two variable in the above graph for my approach to be supported by the data. 

However, time to cherry pick.  If we look at the winner, Dan's ranking in terms of slowing down during the race, he ranks in only 16th place out of 23 runners under 10 hours,  in terms of slowing down the least.  He has a massive slowing down percentage of over 17%, but yet quite easily wins the race!  One runner, Antonia Johnson, 3rd placed women, actually run her fastest split of the race during the last 10 miles.  Second place male Craig Holgate also displays some, in my view, less than ideal data.  How much quicker, and higher up would have these two runners finished if they had adopted a less 'strange' pacing strategy???  None know, hence why pacing is "Still a Mystery!"  

Well enough for tonight, it wasn't as brief as I thought.  They never are!  Time to sign off, again from a quote from Tom from Marathon Talk.  

"I'd rather know I was wrong than think I was right"  Tom Williams, 2011.  

Will we ever know in terms of pacing, what is the wrong or right strategy?  

Stuart  

PS  You may recall that within my recent Endurancelife Sussex Coastal Trail Marathon posts I mentioned Scott Forbes, who finished in third place after he started earlier with ultra runners and the slower marathon runners.  Well a bizarre thing happened the other day.  I was sorting out a few filing cabinets / folders in my office and came across an old 220 Triathlon magazine from 1996.  

  The reason that I had kept this specific issue of 220 was that there was  photo of me and my wife Frances on our wedding say in it.   

  Anyway, I started flicking through the pages and got reading the article on the French Triathlon Tour that was a pretty unique event that had taken place in 1996, which involved the top triathletes in Europe, racing a triathlon every day for over a week!  I then noticed that  Scott Forbes from the UK finished in 50th place.  

  Now this got me thinking, could this Scott Forbes from the Sussex Coastal Trail marathon, be the same Scott Forbes, the elite triathlete from the nineties.  Chatting to Scott following the race, he mentioned that he was just getting into ultra running after previously being a mountain biker, but he had suffered a horrendous bike accident, breaking his neck along with many other injuries, and had decided to try ultra running.  I then remembered that back in 1996 while I was studying for my Masters in Sports Science at Loughborough University, every Wednesday at 1:00pm I used to go out with the triathletes and cyclists from the University.  There used to be around 20 or so riders, and we would go for around 3 - 4 hours, staying in a group for the first 2 hours, and then it was flat out coming back.  It was awesome fun.   

Anyway, I began to remember that on one of the rides I got chatting to one of the young students who mentioned he had raced the French Triathlon Tour, and that he was an elite triathlete, which he clearly would demonstrate on the ride back, as the pace got substantially quicker and quicker.  Could this guy I used to ride with most Wednesday afternoons nearly seventeen years ago, be the same guy I raced last month?  Well a bit of searching on the internet, and yes.  I discovered a few  interesting articles on Scott, and it is the same guy.  Amazing, what a small world it is.  And Scott, if you are reading this, hi again from 1996.  You may remember me, I was the ancient 33 year old guy with a faint NZ accent on the Wednesday that used to somehow keep up with the front group all the way back to Loughborough, even though it looked like I was really suffering and dieing.  I'm sure you will remember me with that description!   

As I mentioned after the race.  Come down to the Classic Quarter 44 mile race in June, down in Cornwall, and we can have a good battle there, assuming you don't start at the wrong time!  Sorry, about that dig.  I'm just excited about the prospect of 'pay back day' for the suffering I endured on those Wednesday afternoon bike rides in 1996/97!  Yes, as I mentioned earlier, those rides were great fun!  The interesting article on Scott an airline pilot, is at this link  and a bit more about him as a mountain biker here.  Keep an eye on his name, I'm sure it will crop up in future ultra trail results, hopefully at this June's Classic Quarter!  

PPS I got a phone call yesterday from a company involved with marketing Asics kit.  They had been to the new Trail Running Sussex website, as well as to this UltraStu blog.  They thought that visitors to both the Trail Running Sussex website and my blog might appreciate the latest promo video they have just released on Austrian Ultra Trail Runner CHRISTIAN SCHIESTER.  So I took a look at the video, and it is pretty inspiring, with some pretty good footage, so here is the link.  

But then also today I came across the Guardian Article on Jez Bragg's amazing New Zealand adventure, and if you haven't seen this article, follow this link.  Within the Guardian article there is a link to some fantastic footage of New Zealand.  So two great videos to watch.  

PPPS I have attempted to put a link to my 100km analysis excel file, but it keeps saying file corrupt when downloading!  If anyone would like a copy of the excel file simply zap me an e-mail at franstu@talktalk.net or my new e-mail address info@trailrunningsussex.co.uk  

PPPPS Finally time for bed!