Thursday, 24 April 2014

Good Day/Slow Day Highland Fling Splits

Running ultra marathons using splits is popular, with a range of approaches used, from using ones own splits from previous races on the route, using splits from training through to adopting average splits of previous races.  In this post I'll publish two sets of splits for the Highland Fling race, one set is are based on previous winner time and represent the splits that are likely to what we might achieve is we run the perfect race and finish strongly, while a second set is based on the average splits recorded during the 2013 race but as I believe most runners set out too fast and suffer in later stages using these splits for me represents when things don't go to plan and how you are likely to slow.

Winners splits are consistent year on year

The winner splits I am using are Andrew James's 2011 winning performance of 7:12 where he set the course record.  This course record was broken Lee Kemp last year (2013) where he lowered the record to an astonishing 7:02:50.  However, the route was altered last year due to path upgrading near Drymen, and Lee made a navigation error on route to Rowardennan which lost him time using his splits aren't likely to be as representative of a perfectly run race on the normal route, so I stepped back to Andrew' performance as my gold standard of splits.  

My confidence in these winning splits being pretty near optimal is based on analysis of previous years winners and course records, where there the difference between male winner splits is less 2% from each other, while others in the top ten and behind on average moving increasingly away from how the winners have consistently paced their races.  The following graph shows previous winners in men's and women's category in relation to Andrew's splits.  

Curiously only the two fastest female winners Lucy Colquhoun and Emma Rocha come close to this type of pacing and their times are way out ahead of other female winners.  I suspect the smaller number of international class woman attending the Fling makes the races less competitive at the front end compared to the men's race that has consistently seen near course record race wins over a number of years.  With less competitive races it's possible for a winner to get the pacing wrong and struggle on the day but still able to win.  Tracy Dean's courageous win last year saw here nursing a injured calf through the majority of the race and time and splits consequently suffered but she was still able to pull out a win. In the men's race it's been so competitive that a small slip up in racing will see them overtaken.

The key take home is that winners pace more consistently and evenly than the almost the whole of the rest of the field, the start at an relatively easy pace for them and finish strong while everyone else around them falters.  The "almost" the whole of the rest of field needs to be qualified, when you analysis all splits there are runners further back in the field that pace evenly as well, and my experience with using a HR monitor to guide pace has resulted in pacing that is far closer to winners splits than the average.  

Runners should take encouragement from this, while most go out too fast and suffer as consequence, it is possible to run your own race well, starting off easy enough that you can keep the stress on your body lower enough for spare glycogen stores, avoid early muscle damage and enable the body to keep digesting food and water.  If you start off easy then there is much greater chance of finishing strong, with the bonus of the experience being a positive one where one enjoys the race rather battling through from early in the race.

How to use splits when planning your own race

Knowing just how easy you should start off is difficult, first you need to know what time you feel can likely achieve on the day, then from this you can select the splits to match this time.  As there is no way we can know exactly how well the race will go on the day I believe it's best to not to try and pick on single target time.  

Instead I would advocate thinking about what your perfect race would turn out like and what time you might achieve if everything went to plan and you raced the perfect splits and the best of your ability, this is your time would define your "Good day" target time and the splits to select from this would be from the Winners splits, where you start steady and finish strong.

Not all races go to plan, it could be that we over estimate our fitness and choose splits way beyond our capability and go out too fast and then struggle, it could be that we get cramp or gastric stress that slows us down, or injure ourselves and then struggle for the rest of the day.  Choosing splits that account for this possible slow down provides us with a fallback set of splits to allow us to estimate our finishing time - these would be result in our "Slow day" target time and associated splits where we start a too strongly for our capabilities on the and finish slow.

If you choose your splits well then it's likely you'll be in between your "Good day" and "Slow day" splits, the nearer you are to your "Good day" splits the better your judged the day and paced the race. What will be apparent from the splits I present below is that the "Good day" and "Slow day" splits start close together near the start and steadily the "Slow day" splits drop off the pace and result in a much slower finishing time.  

For instance if I set off with with 1:50 split to Drymen (9:04 min/mile pace) then the "Good day" splits would see me finish in a time of 9:29:51, while the "Slow day" splits for a 1:50 initial split would see me finish in 11:13:21. If had chosen to use the "Slow day" splits for a finishing time of 9:30 we would have to do the Drymen split in 1:33 which is blistering 7:41 min/mile pace.  Such a strategy is likely to ruin our chances of succeeding on hitting our target time as even the "Slow day" splits would likely become impossible to sustain as we'd be burnt out by the time we reach Balmaha.  

Follow are the splits for the various legs and based on different times for the initial leg to Drymen, note the splits for sub 7 hours course record starts at 1:21, just a shade faster than last year.  The "Good day" splits are based on Andrew James 2011 race, while the "Slow day" is based on the average splits from the 2013 race.  I could label this as "Average day" but I don't believe average splits are best to aim at, instead we should aim for a perfect race, and if things don't go to plan we know we'll still finish in perfectly decent time. An important takeway is that for the perfect race you don't need to start fast to get a great time.



 Leg ratio Completed Leg distance Leg ratio Completed Leg distance Leg ratio Completed Leg distance Leg ratio Completed Leg distance
Winner 0.1930345572 12.13 12.13 0.2703255168 27.09 14.96 0.3003702561 41.04 13.95 0.2362696699 52.87 11.83
Average 0.1633621928 12.13 12.13 0.2641205352 27.09 14.96 0.3171045563 41.04 13.95 0.2554127157 52.87 11.83



























Drymen Leg Pace Rowardenan Leg Time Leg Benglais Leg Pace Tyndrym Leg Pace


























Good day 01:20:00 01:20:00 06:36 03:12:02 01:52:02 07:29 05:16:31 02:04:29 08:55 06:54:26 01:37:55 08:17
Slow day 01:20:00 01:20:00 06:36 03:29:21 02:09:21 08:39 06:04:38 02:35:17 11:08 08:09:43 02:05:05 10:34













Good day 01:21:00 01:21:00 06:41 03:14:26 01:53:26 07:35 05:20:28 02:06:02 09:02 06:59:37 01:39:09 08:23
Slow day 01:21:00 01:21:00 06:41 03:31:58 02:10:58 08:45 06:09:11 02:37:14 11:16 08:15:50 02:06:38 10:42













Good day 01:25:00 01:25:00 07:00 03:24:02 01:59:02 07:57 05:36:18 02:12:16 09:29 07:20:20 01:44:02 08:48
Slow day 01:25:00 01:25:00 07:00 03:42:26 02:17:26 09:11 06:27:25 02:45:00 11:50 08:40:19 02:12:54 11:14













Good day 01:30:00 01:30:00 07:25 03:36:02 02:06:02 08:25 05:56:05 02:20:03 10:02 07:46:14 01:50:09 09:19
Slow day 01:30:00 01:30:00 07:25 03:55:31 02:25:31 09:44 06:50:13 02:54:42 12:31 09:10:55 02:20:43 11:54













Good day 01:35:00 01:35:00 07:50 03:48:02 02:13:02 08:54 06:15:52 02:27:49 10:36 08:12:08 01:56:17 09:50
Slow day 01:35:00 01:35:00 07:50 04:08:36 02:33:36 10:16 07:13:00 03:04:24 13:13 09:41:32 02:28:32 12:33













Good day 01:40:00 01:40:00 08:15 04:00:02 02:20:02 09:22 06:35:39 02:35:36 11:09 08:38:03 02:02:24 10:21
Slow day 01:40:00 01:40:00 08:15 04:21:41 02:41:41 10:48 07:35:47 03:14:07 13:55 10:12:08 02:36:21 13:13













Good day 01:45:00 01:45:00 08:39 04:12:03 02:27:03 09:50 06:55:26 02:43:23 11:43 09:03:57 02:08:31 10:52
Slow day 01:45:00 01:45:00 08:39 04:34:46 02:49:46 11:21 07:58:35 03:23:49 14:37 10:42:45 02:44:10 13:53













Good day 01:50:00 01:50:00 09:04 04:24:03 02:34:03 10:18 07:15:13 02:51:10 12:16 09:29:51 02:14:38 11:23
Slow day 01:50:00 01:50:00 09:04 04:47:51 02:57:51 11:53 08:21:22 03:33:31 15:18 11:13:21 02:51:59 14:32













Good day 01:55:00 01:55:00 09:29 04:36:03 02:41:03 10:46 07:34:59 02:58:57 12:50 09:55:45 02:20:45 11:54
Slow day 01:55:00 01:55:00 09:29 05:00:56 03:05:56 12:26 08:44:09 03:43:14 16:00 11:43:57 02:59:48 15:12













Good day 02:00:00 02:00:00 09:54 04:48:03 02:48:03 11:14 07:54:46 03:06:44 13:23 10:21:39 02:26:53 12:25
Slow day 02:00:00 02:00:00 09:54 05:14:01 03:14:01 12:58 09:06:57 03:52:56 16:42 12:14:34 03:07:37 15:52













Good day 02:05:00 02:05:00 10:18 05:00:03 02:55:03 11:42 08:14:33 03:14:30 13:57 10:47:33 02:33:00 12:56
Slow day 02:05:00 02:05:00 10:18 05:27:06 03:22:06 13:31 09:29:44 04:02:38 17:24 12:45:10 03:15:26 16:31













Good day 02:10:00 02:10:00 10:43 05:12:03 03:02:03 12:10 08:34:20 03:22:17 14:30 11:13:27 02:39:07 13:27
Slow day 02:10:00 02:10:00 10:43 05:40:11 03:30:11 14:03 09:52:32 04:12:21 18:05 13:15:47 03:23:15 17:11













Good day 02:15:00 02:15:00 11:08 05:24:03 03:09:03 12:38 08:54:07 03:30:04 15:04 11:39:21 02:45:14 13:58
Slow day 02:15:00 02:15:00 11:08 05:53:16 03:38:16 14:35 10:15:19 04:22:03 18:47 13:46:23 03:31:04 17:51













Good day 02:20:00 02:20:00 11:32 05:36:03 03:16:03 13:06 09:13:54 03:37:51 15:37 12:05:16 02:51:21 14:29
Slow day 02:20:00 02:20:00 11:32 06:06:21 03:46:21 15:08 10:38:06 04:31:45 19:29 14:16:59 03:38:53 18:30













Good day 02:25:00 02:25:00 11:57 05:48:03 03:23:03 13:34 09:33:41 03:45:38 16:10 12:31:10 02:57:29 15:00
Slow day 02:25:00 02:25:00 11:57 06:19:26 03:54:26 15:40 11:00:54 04:41:28 20:11 14:47:36 03:46:42 19:10

For myself my own targets for this years race (this Saturday) are:

Platinum : 9:30hrs, unlikely but if everything went perfectly and raced above expectations

Gold: 10:00hrs , a more realistic goo day target, I would love to get a sub 10 hours, even if just be few seconds

Silver: 10:20hrs, I think as long as I don't mess things up it should be possible.

Bronze: 10:46hrs, to match match my Highland Fling time of 2012 where I had a good day, but I'd honestly be a bit disappointed if two years on and all my good ultras in Autumn of 2013 that I wouldn't be faster.  Ultra's can be cruel though, you just don't know what's going to happen on the day.

This leaves me looking at a 1:50 to Drymen for me to get within range of my very lofty target of 9:30 hr time, to go out slower than this will likely start reducing my chances of achieving it.  If this was too fast then my chances of doing my more realistic target of 10 hours will be reduced too.  A conservative start would see me look at 1:55 initial which would make a sub 10 hour time more achievable.  

The low risk, lower reward approach would be to head out at ten minute mile pace and arrive at Drymen at around the 2 hour mark.  In my 2012 race I arrived at Drymen in 1:58 and went on to finish in 10:46, but I struggled with low energy levels in the last three miles and had to walk far more of the final miles than I was happy with.  If I am indeed fitter and in particular better fat burner as I suspect I am then I should be more capable of keeping the pace up right through to the end, so even with a slower start I could still realistically be thinking about my silver target of 10:20. 

Based on the "Good day" splits I know that I'd be crazy to start out faster than 9 min/mile pace as it'll likely be unsustainable. If I do end up going through Drymen in a sub 1:50 time I'll know that I need to back off and start conserving my energy better.  If I go through Drymen between 1:50 and 1:55 I know that I'm being competitive but not necessarily fool hardy if it is to be my day and I can manage to stick close to the "Good day" splits through to the finish.

Pacing by Heart Rate

In my recent post How to pace the perfect marathon or ultra marathon I advocated pacing using a Heat Rate Monitor, which will probably lead one to question this post, which one is best?  Race by splits or race by Heart Rate?  If the later what what heart rate to use?

My plan this Saturday is pacing primarily using my Heart Rate monitor with "Good day" splits as a secondary guide to whether I might be over cooking it and also to help project what time I might be on for. If I am able to stay with a heart rate in my target zone for a section and within range of "Good day" split will be reassuring, if I'm too slow or too fast then I will have a bit of feedback on just how well my body is coping on the day - if my HR is high for a given pace then I'll know to be more cautious, but if it's lower then I could be my day I have the headroom to chase a fast time and more optimistic splits.
Finally knowing that I might still be on for a sub 10 hours time could be quite motivating in the last section from Beinglas to Tyndrum.   

The advantage that pacing by Heat Rate has is that helps you even out all the ascents/descents and changes in terrain/weather so you avoid pushing on too hard on ascent, or taking it too easy on a descent.  Running across hilly terrain makes following average pace splits next to impossible, by contrast pacing by HR needs no mental arithmetic, just a quick glance down to the HR monitor watch to check that I'm within a target zone.

Pacing by HR can also be tweaked to fit with average target pace, if you are slightly too fast adjust the target HR down, if you are a bit slow adjust it up.  

In my 2012 Highland Fling race my HR monitor recorded an average HR of 152, in my 2013 Devil O'Highland Race my average HR was 154 (it's a shorter race so higher intensity).  I expect if my race goes to well then I'd see a HR around that of my 2012 Highland Fling race and may actually be a little lower as I'm two years older (max HR goes down with age), and hopefully fitter thanks to my West Highland Way race training,

Based on an assumption of an average HR of 152 by plan is to account for HR drift through the race, breaking the race into three sections:
  1. Milnagaive to Drymen, start first few miles at a target HR of 140, but keep below 150 to Dyrmen
  2. Drymen to Beinglas, the central 6 hours of racing I'll target 150 to 155, with a hard limit of 160 being a Heart Rate to NEVER exceed.  I have found when I exceed 160 in ultra's cramp and/or gastric stress have often been close behind.
  3. Getting to Beinglas in good shape is my key objective, running conservatively be holding myself back  to not got faster than the "Good day" splits and keeping the HR sensible should ensure that my body is able to conserve glycogen stores, avoid overheating and associated fluid loss, and keep my digestion ticking along nicely.  
  4. Once I get to Benglas I'll asses how my body is responding and look to race the last 12 miles to the best of my ability, splits will be out of the window, and I'll relax my target HR allowing it to go higher if my body is able.  If I've got cramp, suffering with gastric stress, muscle fatigue etc. then I'll keep the HR target range conservative.  If my body can handle increasing the effort level then I'll happily let it go up to around 160, and in the last few miles even that limit I'll happily ignore if my body is responding well.
If you are thinking about using HR monitor for pacing as well then using previous average HR for a previous race of similar race is good place to start.  If you don't have this then aiming for around 25bpm lower than the HR you'd see at lactate threshold or average 10k racing HR would also likely be a reasonable target.  For reference by 10k race HR averages around 178, while my max HR is around 190.

Best of luck with race if you are racing and see you there. In case your wondering what I'll look like come race day, here's a photo from last years very wet Devil O'Highlands Race.  Sadly the forecast isn't that great so I suspect my Montane running jacket, worn below, will see plenty of action again.


Posted by at 7 comments:

Wednesday, 23 April 2014

What slows us down, Part 2

In my previous post "What slows us down, Part 1" I dived into the topic of why it's hard to maintain pace when running long races, it's a big topic though, so only covered the topics:
  1. Conscious and sub-conscious, the role of Central Governor
  2. Homoeostasis
  3. Liver and Muscle glycogen depletion
In this post I'll cover just Fat vs Glycogen/Glucose metabolism

4. Fat vs Glycogen/Glucose metabolism

Our muscles and various organs primarily use fat and glucose/glycogen to power the function. When glucose is stored in muscles and the liver it's stored in a slightly altered form called Glycogen.  Our muscles will use the local glycogen preferentially while stocks are still high, but as glycogen stores diminish our muscles have to turn increasingly to metabolising fat or source glucose from blood glucose.

When our muscles work hard they almost exclusively use glycogen as fuel and at the highest intensities burn the glycogen anaerobically (without oxygen) which is great for a quick burst of power but very only uses 1/18th of the energy available in glucose, one of the bi-products of this crude but quick process is lactate which contains the remainder of chemical energy and hydrogen irons that lowers our muscle Ph making it more stressful environment for metabolism and fibre integrate.  A small amount of anaerobic metabolism generates a great deal of lactate so even when running at marathon pace where about 1% of power comes from anaerobic metabolism we could envisage nearly 20% of available fuel at marathon pace being in form of lactate.

Our muscles also can use lactate as fuel through a process called the Cori cycle, this process isn't 100% efficient though, and lactate can only be metabolized using aerobic pathways, so it's only our slow twitch or aerobic fast twitch fibres that will be able to utilize it.  For an ultra runner we should be running more aerobically than a marathoner so the fuel mix will see much less lactate, it will still be there, especially if you push on too hard up a hill.  If you feel the burn going uphill during an ultra it's a strong sign that you are working too hard and should ease off immeditately.

Our brains and gut have a strong preference for using glucose so when glycogen stores are getting low our bodies increasingly reserve the remaining glycogen stocks in our liver for use by the brain. The body uses the hormone Cortisol to signal for the liver to release glycogen and at the same time signal for the muscles to take up less blood sugar.  This is very clever adaptation for survival but it does mean that the longer we run, the more our liver gets depleted the higher cortisol will be, so that our muscles take second dibs on any sugar we consume during the race.   Therefore avoiding high cortisol levels may be crucial factor in making sure that we fuel both our brains, gut and muscles with the food we eat.

A big part in avoiding depletion of glycogen stores in our liver and muscles is how efficiently our muscles can metabolize fat.  Our diet, training and genetic make up all have a role to play in just how much we metabolize fat at different intensities, the following two charts plot how much fat and carbs (glucose/glycogen) that our complete bodies use a different intensities (HR along the horizontal axis, Calories per/hour vertical axis).  The first chart is from data collected when Scottish Ultra runner Caroline McKay was tested in here run up to the Highland Fling in 2013, the second is for a publish paper that looked at well trained athletes.

Fat/Cab metabolism for Ultra runner Caroline McKay
Far/Carb metabolism for well trained athletes.
The differences are startling - Caroline is able to use 70% fat, 30% carbs at intensities we run Ultramarathons at, while the conventionally training athletes came it at around 30% fat, 70% fats.  One of the likely keys to this difference is that Caroline was following a broadly low carb Paelo diet at the time of the tests.  Here ultra marathon focused training will also be a factor, but likely less significant than the diet.

Genetics will also play a role - we all have different mixes of slow and fast twitch fibres, those with more slow twitch have a higher capacity for aerobic metabolism and as fat can only be processed aerobically it puts a strong bias towards in favour of slow twitch dominated athletes.   Also on average females have more slow twitch fibres than males.

Results for ketogenic (very low carb diet) athletes have shown even higher utilization of fats, however, ketogenic athletes have yet to show benefits in races performances, while there a numerous cases of ultra-runners adopting lower carb diets and seeing good improvements to their ultra-running.  Very little research has been done in this area so it's not yet possible to say what level of carb/fat/protien mix be idea, and it's likely to be different from individual to individual.  I suspect through the 80's, 90's and 00's we were consuming too much carbs to be healthy let alone perform to our best in ultra marathons so going back to times before heavily processed food and large amounts of high GI carbs will likely help most runners.

I count myself as just one example of a ultra-runner that has seen improvements with going from a typical western high carb diet (I'd guess roughly 60% carb, 25% fat, 15% protien) to lower carb diet (~35% carb, 50% fat, 15% protein).

Come race day you can't massively alter how much fat your can metabolize, but what you eat and when can alter things a little.  Eating a high Glycemic Index (GI), high carb meals in the days and hours prior to race will push up blood insulin and shift the body to storing blood sugar as glycogen and fat rather and switch off burning of fat.  To avoid this insulin spike you need to take care when carbo loading prior to race, make sure it's of low GI type, and consumed with protein and fat to slow digestion and lower the GI.

During a race our muscle and liver become more sensitive to insulin so that little is required for our bodies to take up and manage blood sugar without risking a big insulin spike and shutting off fat metabolism.  You should be able to eat higher GI foods when doing your ultras, but you'll still need to take care because of gastric stress, big intakes of sugary liquids and solid foods are still likely to cause problem just of different types.  I'll touch on this topic in a later item.  In general I'd suggest consuming a modest amount of easy to digest carbs continuously through a race, consuming as little as 100 carb calories/hour will probably work fine for most runners, especially those able to burn fats efficiently.  

I find it useful to think about fuelling the liver and brain to keep them happy, rather than attempting to fuel the muscles on sugars as you simply can't keep up with their needs - muscles should burn primarily fats during ultras and we should do everything we can to help them do this.

 Another big factor we have control of during the race is our pacing, if you look at the graphs the amount of fats metabolized drops off very rapidly as intensity increases.  The rate of drop off is also much more severe for athletes that can't metabolize fats well so it's a double whammy.  For these sugar dependant athletes it's become far more critical to avoid spikes in intensity, while for fat burners they will likely be able to accommodate an occasional pacing error with less detrimental effect.

For the sugar dependent types pacing as evenly as possible is critical, for this I'd recommend considering racing by heart rate (HR) as I discussed in my recent blog entry  "How to pace a perfect Marathon or Ultramarathon" http://trossachstrailrunner.blogspot.co.uk/2014/04/how-to-pacing-perfect-marathon-or-ultra.html.  Racing by HR will also help fat burners but they can probably be bit less strict on just how even they pace.

Another approach with pacing is to use the splits percentages that the winners of ultra races use rather than the average splits from all runners in a race as is typically done.  From my analysis of Devil O'Highland and Highland Fling Ultra the winners almost always demonstrate the most evenly paced race in the whole field.  Following what the best do on their best days is likely to be much more efficient than pacing to what the masses on average do.  A few of the "masses" run perfectly paced races like the winners do, but the vast majority go out way too fast and suffer in the later stages. Glycogen depletion associated with these fast starts is key factor why they suffer.

I have a post "Good day, Bad day splits" in the works for the Fling, so I'll wrap up now and try to get on to posting this tomorrow - only three sleeps till race day now :-)

Thanks for reading.

Posted by at 2 comments:

Tuesday, 15 April 2014

What slows us down, Part 1

Running Marathons and especially Ultra-Marathon tax out mind and bodies in quite different ways to shorter races, the further you run the less important basic speed is and more important mastering all the other aspects of what effects our running performance.  In a series of posts I'll explore what I've learnt so far about effects our running performance during very long runs and provides some suggestions on what we can do to minimize what slows us down.

What slows us down

In this section I'll quickly enumerate various issues that we have to deal with as the race progress, then in the next section start to look at these in more detail with suggestions on what to do in training and on race day to mitigate how much they'll slow us down.
  1. Conscious and sub-conscious, the role of Central Governor
  2. Homoeostasis
  3. Liver and Muscle glycogen depletion
  4. Fat vs Glycogen/Glucose metabolism
  5. Muscle damage
  6. Injury
  7. Central Nervous System (CNS) Fatigue, and in particular Cramp
  8. Blood imbalances and toxicity
  9. Hormones
  10. Mental Fatigue and Mental State
  11. Heat Stress
  12. Cold Stress
  13. Gastric Stress
  14. Dehydration
  15. Blood pressure
  16. Navigation errors
  17. Terrain
  18. Weather
  19. Night vs Day and the need for sleep.
  20. Pacing + splits
In this Part 1 post, I'll discuss my thoughts on points 1 through to 3, and tackle the others in subsequent posts.  

Disclaimer, I'm not a medical expert so feel free to correct me/add to my own thoughts - it'd be great to spark debate on these topics.  What I write here is is all stuff I've gleaned from books/articles on the web, drawing all this stuff together in the context of marathoning/ultra-marathon hasn't often been done so I think it should make for an interesting discussion - even if it takes a bit of geek to really enjoy this type of pondering! :-)


1. Conscious, sub-conscious and the role of Central Governor

Our brains work at both conscious and sub-conscious levels as we run our races, both sides are entwined together in ways that aren't readily apparent to the conscious thought that we relate to as being the person we are.   Ideas spring up into our conscious thought seemingly randomly, but often it'll be something that one of the sub-conscious activities of our brain need to raise up for us to deal with consciously, be it realising we are thirsty or need the loo through to becoming aware of fatigue or injury.  Understanding that this interplay is at work is crucial to how all our systems mesh together. 

Our sub-conscious brain activities can be quite autonomous and reach down into our central nervous system and down into our gut that itself has a very sophisticated nervous system.  These sub-conscious systems run our body and make sure that our hearts beat, our lungs function, management of  digestion works, heating/cooling of our bodies 

One aspect of this sub-consciousness processing has been labelled in Sport Science as the Central Governor.  The Central Governor is more of emergent behaviour rather than a specific bit of processing or part of brain, it's a likely a collection of different safety mechanisms built into our brains/central nervous system that work to ensure that we will survive whatever endeavour we are pushing our bodies through.

Our conscious thought sits above all these sub-conscious systems and can hint to them that we wish to go faster, but it can only hint, if these systems don't feel it's safe then can be quite unresponsive and reply to us with pain the fatigue.  The is now even speculation that fatigue itself could be an emotion conjured up by our sub-conscious to slow us down.  I believe it's likely that we feel like we've hit "the wall" when running it is likely to be our Central Governor deciding that we don't have a safe reserve of fuel or hydration to push on and passes this message on as fatigue.  This fatigue can be all consuming, where no amount of conscious will can coax us back into swift motion.  This fatigue can also be ephemeral, even small bits of new external or internal information can be enough for the Central Governor to relax it's grip and our pit of fatigue can lift.  

Figuring our what our Central Governor is concerned about can be key to avoid these low points and helping get of them if we find ourselves struggling.  The further and longer your run the more likely you'll hit these low points.  As the Central Governor watches over all our bodies systems, most of the points I raised above are under it's umbrella, all of these elements can individually slow us down, but it's the Central Governor's role to integrate all of this and provide feedback to the brain about overall health status.

It's not often to hear athlete's talk about mind of matter, that from some where  deep they found the will and energy to carry on.  Personally I believe this shouldn't be a battle of conscious will against the Central Governor.  We shouldn't try to beat it into sub-mission but work with it, listen to what it's telling us even if how it tells us can be a bit indirect, if we fix the problems then it will relax it's grip and we can progress.  

In terms of finding energy from nowhere, this isn't really the case, we have the energy systems within to live for months without food for months before death, all we really are doing when we find these hidden reserves is to metabolize fats and proteins for energy, or empty our liver glycogen stores just a bit further than our Central Governor previously thought safe for us to utilize.  Our bodies are perfectly capable of functioning with low reserves, and if you have trained to use your fat reserves efficiently you can actually move efficiently for many hours.

The better we get at listening to our bodies needs and the sooner we address them the happier our Central Governor will be and the less it'll stand in our way and better we can perform.  The better you get at this the less conscious effort will be required to overcome fatigue and the faster you'll be and the more you'll enjoy your races.

It has been found that the Central Governor includes an ability of it to be predict what will happen to our bodies in the future, so if the day is going to be hot then it can slow us before we generate too much heat of our own.  Central Governor also can be trained so that if your are safely pushed your body before it's far more likely to stay relaxed and allow you to push further and harder.

Conversely if something unexpected happens the Central Governor have rapidly become conservative and hold you back.  If you can avoid sudden and unexpected external changes then Central Governor will itself be able to better predict what will happen next and if it's safe then to stay relaxed and not interfere.

2. Homeostasis

While the Central Governor concept provides a umbrella model of the sub-conscious processes that watch over our body and it's physical output (i.e. our pace), the concept of Homeostasis is a companion concept of collection of physical systems in the body that need to be maintained internal balance with various systems kept with in safe limits for us to remain healthy and fully functional.  The further we push our bodies out of Homeostasis the greater stress, damage and ultimately life threatening risk.

The systems that our bodies attempt to keep in Homeostatis include:

  • Temperature
  • Water
  • pH
  • Blood sugar levels
  • Electrolyte balance
Our nervous and endocrine systems control homeostasis using feedback systems provided by various organs.  I also expect the Central Governor will also be part of the loop as management of these systems are directly effected by the intensity of exercise, so if the Central Governor steps in and slows us down by creating fatigue the pressure pushing us out of homoeostasis can be reduced.

At a conscious level we can also monitor what systems that need to be kept in Homeostatis and react to it or even better plan ahead so that we can alter what we do, wear, or consume to help our bodies remain in Homoeostasis.

3. Glycogen Depletion

Usually when runners think about Glycogen (the form of sugar stored in our muscles and liver) depletion we think of our muscles running our of Glycogen and this causing us to slow. While this is big factor for us to contend with it is far from the mos critical one in terms of the risks of Glycogen depletion as our muscles can turn to metabolising fat for fuel.  The more slow twitch fibres a muscle has the more capable it is of metabolising fat for fuel.

By contrasts the brain can not directly metabolize fat, it relies primarily on blood sugar for it's function.  If our blood sugar drops then our brain will begin to fail, early signs will be poor brain function, but if blood sugar goes lower we loose consciousness, and if lowers still further we will die.  The organ in our body that has the task of maintaining blood sugar is our liver that has stores of glycogen that it steadily releases into our blood stream as required.  If our liver becomes seriously depleted of glycogen it can turn to glycogenesis (converting protein to glucose) and ketosis -- converting fats into ketone bodies our brains can use in place of blood sugar.  However, these systems don't readily take up the slack.

Given the critical nature of blood sugar to our brains and how it's the liver that required to maintain blood sugar the level of glycogen depletion in the liver is crucial organ for the Central Governor to track.  If the Central Governor predicts that we are exhausting our liver glycogen stores then it will fatigue us to dramatically slow us down until the demands are low enough to be taken up by glycogensis and ketosis.  This slowing might mean walking right down to needing to lay down and sleep.

Another organ that is reliant upon blood sugar is our digestive system.  When blood sugar is low it's ability to digest food and water is impaired.  This may be a factor is why gastric stress can plague us during the second halves of ultra-marathons.

Given the reliance of our brains and gut function in blood sugar levels and their reliance upon the liver to maintaining it, avoiding liver glycogen depletion is likely more important to avoid than muscle glycogen depletion.  When we eat during an ultra-marathon consider foods that replenish the liver efficiently and maintaining blood sugar rather the viewing food as fuel as fuel for our muscles. 

Glucose gets absorbed via the small intestine into the blood stream, while Fructose (fruit sugar) and Lactose (milk sugar) get shunted directly to the liver.  We can't absorb as much Fructose and Lactose as Glucose so it doesn't make sense to just rely upon these pathways, instead the most productive route is likely to consume something like a 2:1:1 mix of Glucose, Fructose and Lactose.   

Glucose can be consumed in the form of complex carbohydrates rather than straight Glucose, the digestive system breaks down the complex carbohydrates down into Glucose which is then absorbed into the blood stream.  Carbohydrates takes longer to digest than Glucose so provide a steadier release into our blood streams so generally is likely to be preferable for longer races.

The Central Governor also watches what we eat and uses this into own predictions.  It has been found in study that even washing your mouth with sugary drink and then spitting it out can fool the Central Governor into thinking that glucose is safely on it's way and that it can release it's grip on our pace and we can feel a boost of energy.  This isn't something you'd want to do during the first part of long race, but near the end where gastric stress can be limiting what you can consume it can be a useful trick to coaxing your body over the line. 

--

In Part 2 I'll work through more items on my shopping list of what slows us down, I'll try to get to this over the next week.
Posted by at 1 comment:
Subscribe to: Posts (Atom)