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.

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.

Thursday, 3 April 2014

How to pace the perfect Marathon or Ultra-marathon

In search of Optimal Marathon and Ultramarathon Pacing.

The general rule for pacing that is preached by the best coaches and sports scientists is an even split or slightly negative is optimal, and this is prescribed for elite's and every day runners, but is this sounds?  I'm not one to take things on face value, but an inquisitive sort I've thought about the topic extensively and tried out things in my own racing.  The more I've looked into the topic the more convinced I have become that this approach is sound.  This view is based on analysis of what elite's use, and also my understanding of physiological demands that the runner is placing themselves under.

Previously I wrote about elite marathon pacing is my post  2013-London-Marathon-Elite demonstrate folly of Positive Split.  Another great discussion about elite marathon pacing can be found the Science of Sport website, relevant articles : Wilson Kipsang’s marathon world record: Pacing and splits, Geoffrey Mutai: 2:04:15, misses WRHaile Gebrselassie World Record 2007.  There is also a convenient thread for all their marathon analysis.  If you real all these bits of analysis it becomes clear optimum pacing for elites is even pacing, with big penalties paid for times when athletes surge or push on too hard at any one stage.

Another hint that even/negative pacing is provided in a quote from an Jez Brag in an interview published in Ultra Tales:

"Jez Bragg: From my experience the best way to find the ‘magic’ ultra running gears is to be patient, and start steadily. Even pacing, or ideally running negative splits, is the ideal approach to achieve this. By ‘magic’ gears I mean when you settle into a strong pace that feels effortless and like you can go on forever. It does happen; it is possible. That’s how the really special ultra running performances are achieved. The bottom line is that it’s very individual and it’s a case of finding out what works best for you."

Not only does Jez say even pacing is best, but this is exactly what he does - his course record on Devil O'Highlands is almost perfectly evenly paced. Last year I did some analysis Devil O'Highland splits, but alas been too rushed off my feet to write it, the short story of this analysis is Jez' course record stands out clearly as the strongest second half ever run on the route.  The pacing that female Devil O'Highlands record holder,  Lucy Colquhoun, was also very close to even pacing.  This pattern is repeated in analysis I've done of the Highland Fling as well. Whether it's marathon world records or local ultra marathon records, the theme is consistent:

The best of the best run with very close to even pacing.

Muscle Fatigue and Muscle Damage

All marathoner will suffer fatigue and portion of this will be down to muscle damage.  Damaged muscles are less efficient so require more energy to generate the required forces, and also results in greater perceived effort level to maintain force output and pace.  Not only does this chime in with my own experience but studies have also shown how muscle damage accumulates through longer races, I guess it's one of items that is common sense and common experience.

I believe the amount of muscle damage and general muscle fatigue that we accumulate is directly related to pace that we have already run at for the preceding miles.  Running at 7:00 min/mile pace for 13 miles leaves the body with much greater muscle damage and glycogen depletion than running at 7:30 min/mile for 13 miles.  I do not believe the relationship to be linear, running 5% faster won't lead to 5% more muscle damage and glycogen depletion, but will lead to more than 5%.  Exactly how much I don't know, but I know for sure from my experience training and racing it's not linear, going a little bit faster can create a lot more damage.

In my articles from last year on the effect of fat vs glycogen utilization and  pacing strategies on glycogen utilization I touched upon the non-linear relationship between glycogen and intensity, one of the graphs that I included show how rapidly glycogen rises as intensity rises (this is based on study data of well trained athletes), I'll reproduce here so you can see how small increases in intensity have a big effect on how much fat and glycogen(carbs in the graph) you'll need:
My guess us that rate of glycogen depletion and muscle damage are correlated, although a causal link might not be direct.  The bottom line is the faster you run the faster you deplete glycogen and the faster your damage.  The fact that the relationship is non-liner it's likely we'll pay a dis-proportionate amount for going too fast over any particular section.  This is something that can been with the elite marathoners - an surge too early or too hard can blow a field apart and often kill the chances of the one pushing the surge.

Could a Positive split optimal?

Positive split has some advocates, even if they are far outnumbered by the those advocating event splits. In the British ultra-marathon scene Stuart Mills is one such advocate of positive splits with his "run as fast as your can for as far as your can" philosophy of pacing.  Could this approach be view be optimal?

A positive split strategy deliberately has the first run faster, but this does mean you are creating more more muscle damage and greater glycogen depletion in the first half of the race than an even or negative split strategy.  With more muscle damage you physically have to expend more energy per mile to cover the second half.  With greater glycogen depletion you also have to draw that greater energy contribution from your fat reserves, which in turn means greater oxygen load as well as greater perceived effort level to maintain pace.  Carrying a lower efficiency over the second half of the race will mean that the total energy requirement for a positive split will be greater than that of even or negative split.

Now Stuart's hypothesis is that in response to this muscle damage will enviably slow down and should plan for it.  Stuart's uses his own analysis of London marathon results that show the vast majority of runners including elites positive split, and my own analysis of ultra-marathon also support the observation most athletes positive split.  What Stuart then claims that this means positive split is optimal.  I can't figure out why he believes this to be sound conclusion.  To me it's akin to saying because on average the UK population is getting more overweight we should all therefore should aim to gain weight. To me all Stuart's analysis proves is that on average runners slow down in marathons, however, it simply isn't at all useful at telling us what is optimum - you have to use other types of analysis for this.

From a theoretical standpoint I can't see how running a positive split could be beneficial.  It requires more energy due to having to carry greater muscle damage through the second half of the race.  It requires you to run faster at the start of race before your body has fully warmed up and moved from anaerobic to aerobic metabolism wasting precious glycogen.  There is also a physiological price to pay - slowing down is demoralizing, as is being passed by runners who are looking stronger and fresher, you also have to carry yourself on fatigued legs that with every step eat into your soul and will to maintain the pace.  Going out fast and then hanging on is really tough mentally as well as physically.

Having followed Stuart's blog for a few years I do wonder if this last observation may be a key to understanding why he advocates a "Going out as fast as you can for as far as you can" - could it be this pacing approach makes you feel like you've run the absolute hardest and put in the most effort you could have at all points in the race.  It makes you feel that you put your all into all, you suffered for your performance so it must be the fastest you could have run.  

This logic ignores the fact that such pacing causes greater muscle damage, dehydration and glycogen depletion and erodes your mental state, so while it might feel that you are running as fast as you can at any point in reality have to slow down more in the second half than you save in time by running fast in the first half.

Stuart's performance can be a bit hit and miss.  Some races he runs well and has won some huge races, but these all balanced with other races where things don't go right, or where it seems like after one third or half way he simply gives up racing completely.  Stuart often puts this less successful races down to lack of mental as much as physical preparation, but perhaps the pacing strategy is high risk and contributes to these days that don't go so well.  For these races that don't go well perhaps "Run as fast as your dare, or as far as you care" might be a more suitable signature.

I haven't yet seen a compelling argument why positive split might advantageous, and I've yet seen any good real world data to illustrate that it is appropriate for any one, let alone the average runner who is mostly likely to suffer serious muscle damage and fatigue from pushing pace early in long race.  I can't help feel a bit frustrated with Stuart.  He is massively talented runner that has so much potential, but for me I feel it rather squanders it on a less than rational pacing strategy.

What might be optimal pacing look like in practice?

So what should the runner do?  Even or slight negative split looks best from a theoretical standpoint (looking at muscle damage + glycogen depletion, heat stress and dehydration), and is backed by what pacing strategies that world top long distance athletes use when they run their best races.

In practice  one should run the first 15 minutes slower than your average pace to allow you muscles to warm up to temperature that it operates mostly efficiently at - start too fast an you are far more anaerobic and burn precious glycogen and increase muscle PH - which in turn leads to more fatigue and muscle damage.  Once past this easy start and your are fully warmed up you then steadily approach your average pace/intensity that you then aim to maintain for the majority of the race.  If the race has been run well then in the final miles it's then possible to pick up the pace a little and run a strong finish with what glycogen stores are remaining.

While I believe this to be an optimal strategy is hard to achieve and most runners aren't taught or practice pacing enough to do it.  Running the first few miles at slower than your target pace is especially hard as adrenalin is pumping and everyone else around is tearing off.  Adrenalin keeps hiding the true cost of the damage you are doing to your muscles and your prospects of running a good marathon - adrenalin prompts the the release glucose from your liver so you feel a buzz of energy, and reduces perception of pain and fatigue, which is great for a 10k, but not really what you want for a marathon.

For a marathon you need to make sure your glycogen stores in your liver don't empty too quickly, but are called upon steadily through the race.  If the body spots that liver glycogen levels are getting too low it actually creates the emotion of fatigue and slows us down, from their on it's a battle to stay focused and keep the adrenalin pumping because if you don't your body starts shutting down.  Once the adrenalin starts subsiding and the true state of damage and glycogen depletion is revealed it can be rather difficult to keep going.  I believe this is the wall that so many marathoners hit - it's not actually a hard limit of glycogen depletion but the central governor shutting things down as things have gone too far out of homo-stasis at too fast a rate.  These are the key reasons way it's so hard to run a marathon well.

How might an average runner achieve optimal pacing?

So how does an average runner run the optimal pace?  Being realistic, practice, and using tools.

Being realistic is really down to judging just what time you are likely to be able to achieve.  Marathon time calculators like the McMillan are based on what elite runners can do rather than average runners.  Average runners rarely have the aerobic, structural and metabolic resilience to be able to convert their 10k times to great marathon times like the elites.  This average lower reliance than the elites means you need to be more conservative about your time goals.

Practice is about running the target race pace regularly, getting a feel for the breathing, cadence and general feel for that pace.   As you approach your peak training and go into taper you need to speed more and more time at this pace to dial into it.  Dialing into the intensity/breathing is important is you need to run any hills at the same intensity and not judge them by pace.

Tools, here is something that may well be the crucial bit to helping elevate an inexperienced runner into a pacing god.  Heart Rate (HR) monitors are great for telling us just how hard our bodies are working.  While adrenalin may hide our actual effort level making fast pace seem easy and HR monitor will tell us exactly what is going on.  It's the face pace that does the damage so if the HR monitor values are high is indication that are likely incurring more damage than we are aware of.

HR monitors aren't flawless  - they can mis-read at times, and the thanks to natural HR drift the HR trace for optimal even pacing leads to a steady increase in HR from start to finish.  The mis-reading is typical down to poor/compromised contact, wetting a HR strap properly helps avoid this.  With the HR drift just what HR to aim for each stage is something that is likely to be personal, different runners experience different amounts of HR drift, and adrenalin can also elevate the HR for a given pace so if it goes up and down through the race what to aim for can change.

As a starting place one can use the HR guide suggested by the MARCO calculator:

    http://feelrace.com/fr.pl?th=MARCO

From the Loch Katrine marathon that I ran 10 days ago I had a bash at using the MARCO HR guidelines. In a practice run 6 days before the marathon I ran a half marathon route on similar undulating terrain using the HR profile suggested by the MARCO calculator.  What I found is that my first mile was 15 seconds per mile too slow compared to the MARCO calculator, but in the second half on my run I had to run 30 seconds per mile faster than my planned pace.  This trail run told me that my starting HR needed to be higher and my HR drift was slower so I didn't need to target increasing my HR through the race at quite the same rate.

Race day is where it counts, does pacing by HR work?

Come Loch Katrine race day I used my HR monitor and the general principle of increasing HR through the race suggested by the MARCO calculator with tweaks based on my experience with my HR trail run, and also tweaking it on the day.  My aim for the day was to use the marathon as a training run so not push on too hard, and if possible set myself a PB with a target time of 3:30.

The Loch Katrine marathon is extremely hilly so each mile I either got ahead or behind my target average pace of 8min/mile, so I had to trust that pacing would even out.  I hit the turn around point in 1:45:09 which is far more luck than judgement to get that close, but getting so near to this just by using HR and tweaking it little bits each mile to how things were progressing is what got me in the right ballpark.  The tweaking I was doing was to lower my average HR I was targeting for each mile as my HR drift was less than I expected even compared to my half marathon trail run.

Thanks to less hills in the miles after the half marathon point by mule 16 I got ahead of my 8min/mile target without needing to up the intensity, but once I hit the hills between mile 17 and mile 22 my average speed dropped and I down a couple of minutes my the top, but as the downhill miles came I gradually got back on target.  All the while I was using my HR monitor to judge whether to slow down or speed up.

Once I got to mile 23 I was only just behind my target pace, and although it was only meant to be a training run I found myself picking up the pace, really just for fun.  My energy levels had been rock solid all through the race, my legs were quite fatigued from all the downhill miles but I overall I felt great so just pushed on.  The nearer I got to the finish the more I took the breaks off and ended up finishing the last mile in 6:10, and the last quarter at 5 min/mile pace.  Within the crazy finish I would have hit my target of 3:30 quite comfortably, but with the fun last few miles I did it in 3:26:50, nearly a 6 min PB on much hillier course than the Edinburgh marathon course where my previous PB of 3:32:26 was set.

Now I am capable of running a faster marathon, as I wasn't racing it, so I ran the first 23 mile at a slower pace than what I likely capable of.  Running such a big the negative split I did thanks the overly fast last mile isn't optimal in any way shape or form - this occurred because I was playing, not racing.  If I were to race a marathon I'd run the whole thing close to same intensity and pace.  I would certainly struggle more in the last few miles if I were racing simply because of the accumulated fatigue associated with running faster, but that's racing.  My target for sure would be even intensity and even splits.

When scaling up to ultra-marathon I have also found running by HR to be really beneficial.  In my three ultras last Autumn I raced them all far better than my previous ultra record had suggested likely.  One part of this improvement was changes in my diet to higher fat/modest carb diet so I have become better are burning fats and sparing carbs, but a big part of it is getting my pacing right - in my case by running to a constant HR. Targeting a constant HR lead me to run the first halves comfortable and then finish strong.  In my analysis of Devil O'Highland splits my own first half/second half pacing had a small positive split, but 0.7% different pacing than the winner, who just so happened to also run the strongest second half of all the people last year, and the closest to the pace that Jez and Lucy used.

Could it be coincidence that I paced in a very similar way to the best of the best or is it an indication that they run with an even pace and that running with a near constant HR is a good proxy for this intensity and pace?  Personally I can't think of more compelling indicator of just how effective pacing by HR can be.

Probabilistic pacing

Since even and negative splits are common mantra's for runners, me advocating the same really isn't novel.  My positive experience and advocacy of pacing by HR aren't unique either.  Before I wrap I'd like to put forward an idea/why of thinking about pacing that I haven't see discussed before - Probabilistic Pacing.

What is Probabilistic Pacing?  My idea is that we can view our race statistically, where each mile we run and how we run it effects the probability of achieving a particular goal be it time based, place based or just ability to finish.  What you do in each mile can improve your chances of succeeding in your goal or diminish it.   I believe we can simply view this as at high level of conscious thought - i.e if I push on too hard up this hill I increase the risk of cramp on the other side, or depleting my glycogen reserves too much, or to decide to hold back on descent to avoid going over an ankle, this high mental level of Probabilistic Pacing strategy could be partly thought as our Tactical brain.

I don't believe this idea of Probabilistic Pacing is just high level associated with conscious thought processes, I believe the Central Governor Theory suggest that at a sub-conscious level our brain/central nervous system is making calculations all the from external and internal factors to judge whether we are pushing our bodies too far out of homo-stasis as to be safe. If the Central Governor judges what we are doing as potentially damaging or dangerous then passes on it's assessment as the feeling as pain and fatigue to the conscious part of brain.  The further out of homo-stasis we get, or look likely to get, the stronger the Central Governor will dampen our ability to push on, hitting the wall/boning is likely more a manifestation of Central Governor taking charge than actual complete exhaustion.  Conversely if Central Governor judges what we are doing as safe it leaves us alone to run a good pace.

The high level tactical side to Probabilistic Pacing is really about us consciously setting a particular pace that will most likely get us to finish in one piece and at our goal pace/position, as well as working out what our body needs right now to maintain it's workload and also what we'll need next.  In an ultra-marathon this type of mental process has to include thoughts about navigation - do I need a check the map, is the route clear/familiar enough for me not need to check?  Do I need to eat now or later, do I need to drink?  Do I need to pick up some more clothing at the next check point?  Will I need my head touch?  In all these questions we are weighing up the probability that different help or hind our progress.

Probabilistic pacing relates to how fast or slow to run each section in that if we run faster we increase the probability that we'll deplete glycogen more, increase heat stress, sweat more, be able to digest less so absorb less calories and less fluid - running faster reduces can even reduce the probability of finishing at all.  If we run slower we help our bodies stay closer to the safe homo-stasis that it loves, and increase our chances finishing significantly.  However, if we want to achieve a personal best then we have to make a judgement and work out just how much risk are we willing to take with crashing and burning before the finish.

Now the Central Governor is also making these computations and if it decides to take control and cause massive fatigue then it doesn't matter how much me want to finish in certain time, if it feels that you are endangering yourself then it'll call a day and we can very rapidly feel massively fatigued and unwell. The Central Governor does like suddenly changes, non linear events are very hard to judge so it's natural for our safety systems to be conservative.  However, if we keep things smooth and linear our Central Governor is able to trust in what we are doing more and less likely to shut things down. An analogy that springs to mind is that boiling a frog, if you toss it into boiling water it'll jump out, while if you lay it cool water and let it slowly warm up it won't notice that things are getting hot.

Even pacing has the advantage that our bodies systems are steadily taxed and in way that is linear and predictable.  If the Central Governor sees that we are steadily depleting glycogen but at the rate we are burning it we will still have a safe amount left in our liver by the finish then it'll be happy and let us continue.  If we start fast or do a surge we inject a rapid and non-linear increase in rate of glycogen depletion, the heat stress on our bodies rapidly rises, our reserves of fluids get more rapidly depleted, again it's non linear, a modest increase in speed and we have to sweat much more, all of this is noticed and taken into account of by the Central Governor and makes it all more like to decide to create the fatigue that slows us down.

Listen to your heart

This probably all sounds rather complicated.  How are we supposed to use this in our next marathon or ultra marathon?  My advice is simple, listen to your heart.  I don't mean in the happy clappy, spiritual way, I mean quite literary, your heart is one of the best measures of physiological and physiological stress. The fantastic thing is we now have HR monitors that allow us to track ever beat.  We can now look down to our wrist and immediate now just how hard we are working.

With pacing by HR the absolutely simplest way is to run to constant HR.  Due to HR drift this will lead to your slowing through the race, but as long as you pick as sensible target HR this slowing shouldn't be too dramatic and just lead to a modest positive split, so it might not be optimal but it will be not far off.

A refinement on just running against a constant HR is to factor in HR drift so that your pacing goes from a small positive split back to a even or slight negative split.  The MARCO online calculator can be used as a guide for marathons, but as I've found out the HR drift it assumes may not be appropriate for you.  Using your HR monitor in training and seeing how pace and HR drift are associated can give you an idea what is appropriate for yourself.

The nice thing about using HR as guide to pacing is that it works for ascents and descent telling you exactly how hard it's safe to push on up and hill or how fast you can safely run the descent.  It also tells you when heat stress is affecting you, if it's a hot day your pace for a given HR will be lower, but as we sweat more and use more glycogen when we are hot we can't race as fast when it's hot anyway so having the HR reading guide us to slowing down is exactly what we want.

If you are using your HR monitor as a guide during a race and find that you a feeling better than expected, or worse then your can up you target HR slightly to adjust things to speed up or slow down. I used this strategy when I did my three ultra's in the Autumn of 2013, each time I was hit with cramp I dialled by the intensity, reducing my target HR by 5 bpm till any further hints of cramping had subsided then I let the HR target rise back up.

One can also look at the average HR you set as a target in terms of probabilities - which brings us back to Probabilistic Pacing concept.  Targeting a higher average HR will lead to running faster, but increase the risk being unable to maintain the pace or worse failing completely, targeting a lower average HR will lead to slower time but much better chance of finishing.  Judging the right HR to use on the day is difficult, but if you've got a HR record of previous events then you can use the average HR as a basis. If you don't feel as strong as the previous race then it is probably sensible to target a lower HR and if you feel good in the second half up the HR value.  If you feel stronger then a higher average HR might be attainable, but... if you are fitting your HR for a given pace will be lower.   Through tracking average HR and drift from training and other events look for where you feel might be appropriate come race day.  Then on race day itself adjust as necessary for how you feel.

By using your heart as guide what you do is provide a nice stable physiological load on your body that enables your Central Governor to work with nice linear changes in your homo-stasis, it doesn't get any sudden shock and doesn't panic such as making like you feel like you've hit a wall.   By working so closely with your body it will allow you to achieve much more.

Listen to your heart and your body and mind will be strong.

Thursday, 27 March 2014

Loch Katrine Marathon : Race/Training Run Report

The Loch Katrine Marathon is my fourth marathon, but for the first time I was running a marathon as a training run, as part of my build up to doing the West Highland Way Race in June.  My main goal for the race was to provide a training effect of improving the structural resilience of my muscles, ligament, tendons and bones and enhancing my metabolic resilience by training my muscles to burn primarily fats for fuel.

Training vs Racing and Expectations

The training goal meant running a measured race, hard enough to provide a good training stimulus, but not so hard to require weeks of recovery - I wanted to back doing normal training within a week of the race.  As it was primarily for training I didn't do the usual taper,  in fact originally I hadn't planned to taper at all except for a couple of days of taking it easy, but after put in my longest ever training week of 65 miles the previous week my my muscles were feeling rather fatigued and achy so decided upon a five day taper where I did three 4 mile recovery runs and had two rest days where I just did a short walk.  The purpose of this short taper was to freshen myself up and make sure I could run a good marathon, and thus maximize the training effect I could get from it.

A secondary goal was lurking behind the scenes I had already put in quite a few miles in training so far this year, and while I had a few mixed signals about my fitness I had the feeling that I could have a good stab at setting a new personal best without needing to push too hard.  I set my marathon PB of 3:32:26 at the Edinburgh Marathon in 2010, something I tried to beat at the Kielder Marathon in 2011 and 2012 but failed on both occasions, crashing and burning in the last six miles, recording times of 3:54:59 and 3:36:34 respectively.  Loch Katrine is even hillier than the Kielder Marathon course, but  after doing well in the Devil, RAW and Jedburgh 3 Peaks Ultras last Autumn I felt that I was no longer the same athlete, my fat burning capacity had improved, my legs are now toughened up and crucially I am now more experienced and better at managing pace.

Using my training logs, calibrated to previous races, I had a range of estimates of what time I might be able to do and at what level of intensity, if I were to match the fitness of my better recent training runs then a time of 3:30 with an average HR of around 161 look possible.  My average HR for previous marathon had been in the 169-171 range, so 161 looked like a reasonable easing back.  My training had been mixed though, my heart rate drift on longer runs had been low, but my resting HR has been elevated and the calories per mile reported by the HR monitor hasn't that great so I wasn't confident in the predictions and really didn't know what to expect.

Race day

The morning of the race dawned clear and frosty.  I had struggled to sleep through the night, only falling to sleep around a hour and half before I had to rise, and the short sleep I did get was restless.  My body just didn't want to shut down, I felt hot and couldn't get comfortable, it was like my blood chemistry was set up to keep me awake.  When the alarm went off a 6:00 am I got up and hobbled down the stairs with my right knee painful and feeling unstable, it had been fine the afternoon before, taper madness?   Not a good sign, but made worse by seeing my that I had the ashen complexion of vampire victim drained of blood?!  I am used to pre-race nerves but this was quite bizarre.

The marathon happening even if my body had just checked out of the morgue so I made myself my now customary scrambled eggs, oat cakes and beetroot juice drink for breakfast.  A cup of tea helped too, by the time I was ready to leave at 7:10am I had some semblance of readiness.   I headed out into the clear frosty morning to catch my lift to the start (thanks Caroline, Paddy and Chris :-)

We arrived nice and early, sat by the fire at the cafe with hot drinks and swapped ultra-marathon/marathon stories, marathon first timer Chris and I registered and headed down to the start to join the other hundred or so runners lining up for the marathon.

Runners assembling
I spotted a number of ultra-marathon regulars at the start by the harbour, wished them good luck and settled in a few rows back from the start.

Race briefing from race director Audrey McIntosh

Race begins, without the racing...

Just before 9:00 am we were on out way.  A few runners tore off and disappeared into the distance there but for the most part the start seemed very restrained and found myself running gently along around the middle of the park.

My pacing plan was loosely based on the online MARCO calculator, starting easy with my Heat Rate (HR) below 150 for the first two miles, aiming for 8:15 pace, and then let the pace and intensity rise a little once my muscles had warmed up and my aerobic system was fully up and running.  As the route is very hilly I planned to use my HR as a guide to what intensity to run up and down hills rather than going by feel, or trying to match those who were around me.  I expected HR drift to steadily take my HR upwards as the race progressed and expected to need to HR of around 160 by the half way point to keep my pace on target, and to progress upwards towards 170 by the end.  My overall pacing I was aiming for an even split, or perhaps slightly negative.  However, with so many hills, and my own fitness still a big unknown I was prepared to deal with whatever came good or bad.

Normally when doing marathon races I find my HR responds to the race day adrenalin and immediately spikes higher than it would in training for a given pace.  However, I found that I was moving comfortable along and my HR was comfortably staying below 150.  I went through the first two miles at 8:15 pace bang on target, far more by fluke than judgement.   The discomfort in my knee that was apparent when walking up/down stairs had largely melted away too.  Signs so far were all positive.

The views looking from south from the loch side road where stunning, Ben Venue looked glorious capped into a fresh snow, shining brightly against the clear blue sky.   I was torn whether to stop and take a photo but resisted the urge - I was supposed to be in race!  I regret now as I would have loved to be able to share just how stunning the view was.

After the first mile the route starts undulating through woodland, no big hills, but enough to start seeing patterns in pacing that various runners were adopting - using my HR monitor as I guide to keep the intensity roughly constant I found myself loosing ground going uphill, but catching up on downhills. After the second mile those around me where now running at pretty similar average speed so the juggling of places settled down and we all got on quietly with running and drinking up the view.

You have to love those hills

The route starts off quite flat for the first mile and progressively becomes more hilly so by the third mile I had was nearly 2 minutes behind a 8 min/mile schedule required for a 3:30 marathon.  Mile four was more downhill on average so I was able to pull back a minute and looked soon to be back on a 8 min/mile average but then we were faced with the 6 miles of lots of pretty big ascents/descents didn't see any progress on my average pace and was still a minute a half behind by mile 10.

I was however, making my steadily through the field, overtaking people both on the ascents and descents.  At the summit of the hill at mile 9 a small home-made sign had been planted with the words "graveyard hill" with lots of cartoon gravestones placed around - clearly one of race organizers has a black sense of humour as we'd be coming back this way to meet the hill at mile 17!

One of the advantages of racing by HR is that it keeps your effort level going up hill very similar to what it is going on the flat or downhill so the hills don't become the lung and leg busters that might be otherwise.  This even level of intensity helps make sure you are burning glycogen most efficiently - avoiding the anaerobic spikes that can occur if you push on too hard, and also keeps your temperature nearer a constant level which helps your body keeper nearer to homoeostasis, together this all means that your central governor doesn't get any shocks so doesn't need to go to any desperate measures to try and rescue you from over-doing it by causing fatigue to slow you down.


View from graveyeard hill looking towards the Stronachlochar  and the turn round point.

At mile ten the route paces along the west side of Loch Katrine and heads to the turn round point just beyond the hamlet of Stronachlochar where the pier for the Loch Katrine ferry boat arrives/leaves at. The three miles to turn round point is underlating by the hills are all far less steep or long so my average pace increased and found myself comfortably putting in sub 7:30 to 8:00 min/miles.  I kept steadily catching up with and passing runners, mile my mile my deficit was reducing and most surprising was that my HR was staying quite low, hovering around 155 bpm, nicely below my the 160 bpm range that I had expected to need by this point.

A couple of miles before the half way point I caught up with fellow ultra marathon Donald Sandman, in his tartan shorts as usual.  I had met Donald at the RAW and the Jedburgh ultra marathons so spent the the miles to the turn round point chatting about ultra-marathons past and future.  Race leader Andrew Murry breezed passed looking strong already a few miles ahead of us and now heading back home.  A few minutes later Gerry Craig passed in second place looking strong as well.

Half way miracle, 1:45:09

At the half way point I was aware that Donald was breathing a bit harder so without realising it I'm afraid I might have dragged him along a bit too fast for that section.  Once past the turn round point I wished Donald good luck and pushed on.  I checked my watch, 1:45:09 for the half marathon point, I couldn't quite believe it, all those hills, speed fluctuating between 10 min/mile and 6 min/mile and somehow it all averaged out perfectly.

The next few miles heading back towards the hills we were passing the rest of the field who were still heading out to the half way point.  I rather ran out of different ways to call out encouragement.  I was chuffed to be able to spot and call out encouragement to Scottish ultra-marathon legend Fiona Rennie. It seemed like half the field were ultra marathoners!

By mile 16 I was now a minute ahead of schedule, but knew that the next 6 miles were going to be very hilly and would loose all of this buffer and more, so it was a case of keeping steady and relying upon the last four miles of less undulating terrain at the end of the race to get back to my 3:30 target.

HR was still staying below 160 for most of the time, only on the very steep hills was it migrating a bit higher.  Along with less heart rate drift than I was expecting my energy levels were feeling great, no signs of glycogen depletion or low blood sugar despite just drinking just water on route.  The only warning sign that I need to manage was that by mile 16 I was aware that muscle damage in my quads was accumulating - the net effect of running of roads with lots of steep descents.  Perhaps 5 days taper wasn't quite enough?

Once back on the north side of the loch the big hills return, again using the HR monitor helped keep my intensity level down to safe levels, so even graveyard hill didn't present any problems - apart from crawling up it at 12 min/mile pace!

The field had now spread out so while I was still catching runners, I was mostly running on my own.  Running back eastwards meant that the wind was behind us, the sun was beating down and the hills kept coming and found myself sweating enough that my nipples had begun to chaffe and become sore. Rather than risking bloody nipples by the end and wasting previous fluids on sweating I pulled my top off, tied it around my waste and ran for the next 6 miles bare chested.

View from the north side of Loch Katrine, looking south, Highland Cows complete the picture postcard views!
The hills came and went and my buffer disappeared and turned into a couple of minute deficit by mile 21. Thankfully I had now passed the highest point and had some downhill and less undulating miles ahead. Despite mounting discomfort in my quads I was still running strongly and could comfortably power down the hills. At the water point just after mile 22 I caught the first lady, then shortly after passed Chris who had run strongly so far but now was struggling a bit with hamstring that were showing signs of cramping up, he was still moving at a reasonable pace so looked good for finishing in a good time.

Taking the breaks off

With 3 miles to go my quads were painfully but the rest of me was feeling fresh, strong and moving smoothly.  I was now back on schedule for finishing in 3:30, all I now had to do was put away 3 more miles of 8 min/miles and I'd reach my target time and have a nice PB to boot.  After the water stop there was a mile of mostly downhill and I just relaxed and let the pace naturally speed up, looking at my GPS trace now I see that I put that mile away at 6:50 pace, my fastest in the race so far.

At mile 24 I was now a under my 3:30 target, the anxiety about possible cramp or running out of fuel that had plagued the last few miles of previous marathon had evaporated, I was now running fast for the pure joy of running.  For the last few miles I was regularly catching either tail enders of the half marathon or fellow marathoners, I found it easier to pass on words of encouragement to the half marathoners, but with the marathoners felt slightly guilty about finishing so strongly.

Once the final mile marker had passed I just let the breaks off completely and my speed just naturally increased, sub seven minute miles turned into sub six minute miles and the final quarter mile I was in full flight gleefully hitting 5 minute mile pace.  There wasn't any conscious decision to run so fast, there was no mental battle against the pain or exhaustion, for those last few minutes there was none, I just ran that way my body was wanting to run, with me just along to enjoy the ride.

As I tore round the last bend into the finish straight I over took one last runner, just as the photographer was lining up to take a photograph of him.  I had a suddenly jolt of indecision which side of the runner to pass but really didn't have time to choose and passed between the photographer and my fellow marathoner.  I do hope I didn't ruin the picture with me tearing past like a crazed banshee.

As I approached the finish I spotted my wife and our three girls who were all waving enthusiastically from the crowd at the harbour side.  I waved back and crossed the line at near full speed.  I couldn't see a clear finishing line so kept moving swiftly till I arrived at the line of marshals who were handing out medals and suddenly had to jam my breaks on to avoid bowling them over.  Finishing so strongly caused plenty of amusement at the finish and even got a hug and medal from race organize Audrey.

Once I had moved over the side I joined my family, one of the first things I heard was "if you could finish so strongly you clearly didn't try hard enough for the rest of the race!" I couldn't really say well it was supposed to be a training run, average 6:10 pace for the last mile really can't even be explained away as long run with a fast finish... A 25 mile long training run and practising from running away from a very hungry bear would probably be more appropriate.

Marathon PB.  Job done.

Checking with the time keepers I found me time to be 3:26:50 and 14th place overall.  A PB by 5:42 on much hillier terrain, and ten minutes faster than my best Kielder marathoner which has more similar terrain.

My average HR was just 157, well below the 169 average I saw when I last ran the Kielder marathon back in 2012.  The average was also below the 161 average I expected to need to reach my target of 3:30, an indication that my HR drift was well below that assumed by the MARCO calculator and my better than my training logs had hinted at.

My energy levels throughout the race were rock solid.  The only food I consumed on the run was 5 Jelly Babies at the mile 18 water stop, more out of fancying the tasty sweet than concern over energy levels. I drank a small cup of water at each of the water stops at mile 4, 8, 13, 18 and 24.  I never felt thirsty, tired or lacking in energy.  My good energy levels and low heart drift all point to my fat burning capabilities having improved significantly - all great signs for my up coming ultra marathons.

My only real discomfort was that my quads steadily became more painful in the second half of the race. The discomfort thankfully wasn't backed up with any issues with energy levels, dehydration or cramp so didn't effect my form or ability to push on a very fast pace at the end.  The pain in my quads is sign that either I haven't trained with enough fast descents on roads, done enough long runs, or simply that I hadn't recovered enough from a very big mileage week prior to my 5 day taper. Or perhaps a combination of all of these.

Recovery week

For the Monday and Tuesday after the Marathon my quads were very sore so I did a one mile and two mile walks respectively, just to loosen the legs and get the blood flowing.  Wednesday my quads were less sore so I ventured out for a flat four mile recovery run, averaging 10 min/mile pace and HR of 132. Today my quads were still sore but improved over the previous day so I headed out for a undulating local 6.5 mile trail route - my quads were definitely tender on the down-hills.

I will keep doing easy runs until my legs start feeling strong and pain free, fingers crossed it won't last much longer as I need to start building up towards the long hill runs I have planned to train for the Highland Fling at the end of April.

For my previous Fling back in 2012 for my longest training run I completed a 30 mile, 5000ft ascent/descent tour of the three Callander peaks - Ben Guilipen, Ben Ledi and the Callander Crags.  During the race my quads held up really well right to the finish - the only thing that slowed me down was running out of energy - I just relied upon carbs for muscle fuel too much back then.  Today I've addressed the fuel utilization issue pretty well, but given how my quads feel after just 26 miles, let alone the 53 miles required during the Fling, it looks like I'll be in need of doing the three Callander peaks once again to toughen them up.

If I work in a three week taper then I'll need to do the Callander peaks in just ten days time, so really need to recover quickly this week.  I now partly regret being quite so exuberant with my fast last mile, training wise it didn't really make much sense....

But... oh boy it was glorious fun :-)

Thanks

My thanks to Audrey McIntosh for organizing such a great race.  Thanks also to all the volunteers who helped mark the course out so well and did such a friendly job marshalling the course, water stops, and start/finish.

Tuesday, 18 March 2014

Ups and Downs of Training for the West Highland Way Race

I am now three and half months into my training for this year's West Highland Way Race, and just over have three months left to prepare myself to run 95 miles on the 21st of June.  Now in to second half of training I'm getting into the real business end of training, the first real test will come this Sunday (23rd of March) when I run my first race of the the year - the Loch Katrine Marathon, my second big test will be five weeks later when I run the 53 mile Highland Fling that covers the first half of West Highland Way.

Base building

The approach to training for the last few months is to tailor the conventional Aerobic Base Building phase that most Marathon training plans include to make it more specific to the needs of ultra-marathoning.  The goals for this phase has been to:

  1. Develop my ability to comfortably run at the slow pace that will be required on race day.
  2. Use fat as the primary fuel for running muscles at the ultra-marathon pace
  3. Steadily build my structural resilience to delay the onset of fatigue 
  4. Build ability to quickly recover from training and racing   

Previous years I've tried to steadily build up an aerobic base but have almost always been blighted by injury after a two or three months of serious training.  To lower this risk, this year I have built my mileage and intensity up very steadily, cutting weekly mileage and intensity the times when I have felt niggles building.  So far this approach has worked, and while I've had plenty of niggles from my feet through to my back so far have only a needed few days of rest, or easier week has been enough for the niggles to mostly melt away. Elements of training that appear to have helped are:

  1. Regular recovery runs (9 to 10min/mile) pace, with around 50% of volume at around this pace.
  2. Longer runs at an easy to recovery pace, 9:30 to 8:30 pace.
  3. Doing several modest length long runs per week, 
  4. No really long runs, longest so far this cycle has been an 18 miler.
  5. Following more stressful runs with recovery run days
  6. One faster run per week, but keeping pace to just marathon pace and distance at 8 miles.
  7. Regular use of foam roller and self massage to keep the muscles loose
  8. Eating well

Following this approach I have been able to steadily up the weekly mileage from ~35 mile per week in December, to ~45 mile per week in January and then averaged 56 mile/week in February.  In February in one week I pushed the mileage up to 62 miles, which was my longest weekly training mileage up to that point.

My plan for March was to aim for a weekly mileage in the mid sixties, but both calves had become a bit tight by the end of February, with a niggle in the left calf so I decided to put in a down week in the first week of March and only ran 42 miles, this seemed be enough to relax and heal my calves and last week put in a 65 miles, with three long runs of 14 miles, 18 miles and 15 miles each with only a recovery day in between.  There wasn't a prior plan to do all these so close together, but the weather was sunny for once and my body just seemed to be recovering really quickly so I just went out and enjoyed myself.

This week my calves, have been a little tight each morning, my quads have felt fatigued and my hip flexors a bit over stressed so I'll be taking the rest of this week bit easier than originally planned.  I do have the Loch Katrine marathon on Sunday so I'm figuring that I'll get better training effect from the marathon if I am rested properly and the niggles have melted away.   I really can't complain though, 65 miles in week is half marathon more than I ever been able to handle in a training week before.

So far in this training cycle my body seems to have coped really well with the mileage, my recovery from runs has been astounding compared to my usual aches and pains for days after a long or faster run, with niggles melting away with just a small easing back of mileage/intensity.  Times when I've thought I've over done it for sure a day or two later I'm back running smoothly.

In contrast to this excellent recovery the efficiency I've been recording via my Heat Rate (HR) monitor has improved on average, but no where near as much as I usually see when I'm well into training.  My resting HR has also been elevated right through from January to now.  I had a cold at the end of February that raised my HR into the mid 50's, and since it's come down each week but now sits around 46-48 each morning.  Just once in the last month has my HR go done to 45 where I'd normally expect it to be when I'm well into a training cycle.

With this much volume of training I had expected my resting HR to be down at 44 or below - where it was when I was at my peak last October just before the Jedburgh Three Peaks Ultra-marathon.   The only day when my HR was where I expected it to be I had my most efficient day in this training cycle, surpassing what I achieve back in October, but this was just one fleeting day.  A couple of days later I recorded my worst efficiency of this training cycle - my HR elevated my around 10 bpm for a given pace and using 20% more calories per mile according to my HR monitor.  Then two days later my HR was back down, but still not elevated compared to where I would have expected.

Below is a graph of my Effective Efficiency (calories per mile, adjusted for HR drift and hills) from December to mid March.  General trend is downwards, but it's very noisy, far more than I'd expect, and there are so startling spikes.  When I'm at my peak I usually see Effective Efficiency values in the 78 to 80 calories/mile range.  Something I've only achieved on one day so far.

Would the sporadic nature of my resting HR and HR for a given pace suggest that my sympathetic nervous system is all over the place?  Is it a sign of over training?  I'm torn as my recovery rates are really good, but clearly something is quite right.

Thankfully this week my HR has been reasonably stable so far, a half marathon test run I did on Monday was one of my most efficient in this training cycle, with HR drift being very modest.  Fingers crossed things are settling down in time for my biggest challenge this year so far.

Plan for Loch Katrine Marathon

The Loch Katrine marathon will be my fourth marathon, but only my second road marathon.  My marathon PB of 3:32 I did on my first marathon race back in 2010 during a very hot Edinburgh Marathon.  This Sunday's marathon I'll just run as a training run so the actual finishing time is not critical, but... it would be great boost to get close or set a new PB.

My fitness for distance running is now so much better than it was back in 2010 that I should be capable of time in theory of around 3:05 to 3:10 on flat course.  Loch Katrine marathon is very hilly though, I know of estimates of 1800 to 2200 foot ascent/descent so it'll not be far off the challenge presented by the Kielder Marathon than I did in 3:36 back in 2012.   I estimate the hills will probably take 10 minutes off the time I might be able to achieve on flat marathon, so 3:15 to 3:20 might be possible if I had training specifically for the marathon or was planning on racing it.

My plan isn't to race though, my plan is for a tiny 6 day taper, do the marathon without pushing into the red, then have an easy week and be back into full on training at beginning of April in prep for the Fling at the end of April.  To dial down the intensity I have decided to aim for lower average HR than I'd usually see in a marathon - normally I'd see an average HR for 168 to 170 in a marathon, for Loch Katrine I'm currently looking at 161 as my target.  I have a spreadsheet that I plug in the stats for all my runs and have column for estimates of how each run would map to what I could achieve at different races, and the figures currently point to a time around the 3:25 to 3:40 mark being possible at around a HR of 161.

As trail on Monday's half marathon run I used the MARCO to give me an idea of what pacing and HR progression to use during the race for a target time of 3:30 and average HR of 161. During my run I followed the HR guide for each mile segment - progressing from the suggested HR or 145 through to the 161 HR at mile 13.  The MARCO pacing guide for this mile segments suggests progressing from 8:15 pace to 8:01 by mile 13.  The pacing I saw though was 8:30 for the first mile, and 7:30 for the last. So I started too slow and finished way too fast.  The whole second half of my run was too fast, and I ended finishing 4 minutes ahead of the schedule.

The discrepancy with the MARCO calculator probably isn't too surprising - it was a hilly course which will complicate things and all humans are different, and physiologically I was in totally different place - a half marathon training run rather than the first half of marathon race.  However, even we've these factors it would seem that my starting HR needs to be higher to avoid starting so slower, and at least on this training run I saw far less HR drift than the MARCO calculator assumes, keeping to it's HR profile had me running 30 seconds a mile too fast for the last four mile. It felt too fast as well, with my quads feeling fatigued from the previous weeks high mileage and my hip flexors complained in the last few miles, I'm glad that I'm not attempting to run 3:15 right now.

Having a high HR for a slow pace at the start isn't too encouraging, but a lower HR drift is very encouraging so a bit like my up and down resting HR/sporadic efficiency I seem to be getting mixed signals about my fitness/possible over training status.  I'm hoping a five more days of easy paced running will settle things down and allow me to see a clearer picture of my fitness.

Come race day on Sunday we'll find out for sure just how well my body is responding to training.  I haven't done any marathon specific training, I haven't attempted to reach peak aerobic fitness, I've just been building on the key ingredients I'll need come the 21st of June when I line up at 1am to run the West Highland Way.  Even without any specific training for the Loch Katrine Marathon I'm still hoping that I now have the capacity to run a solid marathon and have a stab at an new PB, with the proviso it's the actual training effect that is most important right now so will need to be done without pushing on too hard.

Monday, 6 January 2014

Introducing the concept of "Aerobic Resilience"

I'm now into my forth year of running Ultra-marathons and this year will take my biggest challenge so far - running the West Highland Way Race that covers 95 miles from Glasgow to Fort William. Preparing for this race is both a physical and mental challenge for me, and having a rather analytical streak I'm drawn to try to understand how best to prepare for the challenge.  I did start writing a long reply on a friends blog about my thoughts so far, but it really deserved a blog post of my own, so I've put together my thoughts, a little rough and ready, but should help understand where I'm going.

A mass of advice, but a vacuum of scientific evidence and models

There is huge amount of material in books and our on the web about how different people prepare for marathons and ultra-marathons, really too much material to digest especially as advice can conflicts, and in particular ulra-marathons have almost no scientific studies that might help us understand what might best.  I love an intellectual challenge as much as a physical one so I've been trying to distil things down to key factors that we should be training for when training for marathon or ultra marathon distances race.

Understanding Patterns that emerge from analysing Ultramarathon race results

From my analysis of ultra marathon results I've seen the trend for faster runners to slow less through races and for them to be able to  sustain a greater proportion of their shorter races paces (for instance looking at ultra vs 10k pace.)   I will need to write this analysis up, but as this is quick post I'll leave this for a later series of posts.

There is also a great deal of noise to the data, so while there are overall trends there is huge individual variations.  I'm hoping to come up with a simple but viable model to explain these variations, at least accurate enough to inform how one should train and paces races to get the best performances.

Introducing the concept of Aerobic Resilience

My current model is to view basic "Aerobic" fitness as equating to a runners 10k or half marathon distances where pace is near is tad faster or around the anaerobic threshold, but still the vast majority of energy production is aerobic.  One then introduces a "Resilience" factor that determines how well we can maintain pace as we run further.   A very simplistic mathematically model one could use might be:

  Speed(distance) = MaxAerobicSpeed *  (ResilienceFactor)^Distance

When ResilienceFactor is nearer to 1.0 for the best endurance runners and lower for those who struggle to achieve their potential at marathon or further distances.

The term Aerobic Resilience probably best sums up what I'm trying to encapsulate with this model.

With training for short distance races like 10k and half marathons it's all about maximizing our aerobic fitness, and topping this off with a small contribution from our anaerobic metabolism.

For longer distances like the marathon and beyond the contribution from anaerobic metabolism is less than 2% so it's it's almost entirely a case of maximizing our aerobic fitness.  However, it's not just about aerobic fitness, muscle damage, dehydration and glycogen exhaustion all play a part.  These other factors all combine to give our Resilience on race day.

When training for races of marathon and longer we have to train to maximize the combination of our Aerobic fitness and our Resilience.  Ignore either and you will not make the best of your potential.

For me the key factors in Resilience are Mental Resilience, Structural Resilience and Metabolic Resilience, The ReslienceFactor is the product of these individual factors.

Mental Resilience

Mental Resilience covers out ability to stay focused and positive through a race, to keep on top of discomfort, to monitor all our physical and mental systems and know what to do when areas need more support i..e take a gel, take a drink, take a walking break, get back running.  The mental side also includes the macro level planning over the whole race and management of pace.  For trail races one often has to keep an eye on the weather and navigation, so being able to have a fully functioning brain throughout the race can be crucial to not making costly mistakes.  You can also borrow a bit of Mental Resilience from any support you might have or from other runners, either competitively or collaboratively.  Things outside your own personal body can also impact on your Mental Resilience, for instance getting over taken or seeing what you feel is cheating might impair you mood or judgement on how to manage your own body and race.

Structural Resilience

Structural Resilience covers the ability of our bones, ligaments, muscles, fascias, cartilage, nervous system, digestion and cardiovascular systems to work continuously handling the physical demands placed upon without breaking down.  All these factors are multiplied together, if any one part starts failing then our overall Structural Resilience is compromised, our running economy will diminish as well as put a large strain on our Mental Resilience as the discomfort levels mount.

Metabolic Resilience

Metabolic Resilience covers the ability of our body to metabolise carbohydrates, fats and proteins efficiently.  Our ability to digest carbohydrates, fats and proteins efficiently also plays a part in longer races.  A runner who has poor ability to metabolize fats will almost certainly have a relatively poor Metabolic Resilience so will likely hit the wall, and will be very dependent on consuming carbs during the race.  Runners with ability to maintain a good pace whilst metabolising primarily fats will have good Metabolic Resilience and will require less fuelling during races.

Ingesting too much food when working too hard causes gastric stress, so a poor Metabolic Resilience puts strain on our Structural Resilience and our Mental Resilience.  A runner with good Mental Resilience would not give in, but slow down till the gastric stress passed then push on when the body settled.  This is just one example of how each of the element of Resilience are interconnected connected.

How to maximize Aerobic Resilience?

A simple model of long distance performance like Aerobic Resilience is only useful if it helps inform how we should train and prepare to maximize our performance come race day.  This is a big topic in itself so I'll leave putting down my thoughts for another post or two.  If you feel that this model is useful, or has elements that I should include just let me know, I'd like to refine it over the coming weeks, months and years to help myself and others enjoy training and racing as much as possible.

Sunday, 22 December 2013

Tour of Destruction, Floods and Snow

The last few weeks in Callander have seen a series of Atlantic storms sweep through, in between the wild weather I've got on with my training for the West Highland Way Race, now just 6 months away.  Local trails have mostly been cleared enough to allow passage, but several require clambering around trees. Follows are pictures from three of my recent runs, if you are impatient for festive ones scroll right to the bottom as I played in the snow just before the sun went down.

One of my regular hilly routes takes me from Callander up to and over the Bracklin Falls Bridge then on to Scout Pool, then back down the Backlin Road to Callander.

View of Bracklin Bridge, many branches brought down in the storms.

Beyond the Bracklin Bridge the path heads up hill towards the forestry track, but first you have clamber through this sorry loooking tree that has been blown down across the path.

As soon as your get to the Forestry track you have to clamber through a mighty fir tree that completely covers the junction with the path from Bracklin Falls.

Next set of tress on the way up the Forestry track.

Looking back to all the trees that have already been cleared.

There was once dense Forest here, a football pitch swathe of trees all victim of the storms

More tree clearance

As I emerged from the forestry the exposed edges have been decimated.

Viewing looking north towards local Munroes Stuc a' Chroin and Ben Vortlich, I take the left track down.

Mid afternoon winter sunset, looking down Bracklin Road towards Ben Gulipen with Callander lit up below
A couple of days later I headed around a 6 and half mile loop we locally call the Four Bridges, the route back took me along the cycle path back to the Callander meadows witnessing floods thanks to all the rain that's been sweeping through day after day after day.

Normally a dry field!

Back in Callander with the Meadows Carpoark and playground flooded.
My longest run in December was a 15 mile run from Callander up to Stank Glen.  I squeezed in the run between showers and stayed mostly dry, and even got above cloud base.

Not a great photo, but this used to look very different, another huge swath of dense forest gone, trees blown down at the routes or snapped like match sticks.  The destruction is incredibly localised, some areas are untouched, others every tree in the area has been flattened.

At the head of Stank Glen looking East, 1500ft of descent to come :-)

Emerging out from Stank Glen into the main valley above Loch Lubnaig the clouds boiled away from the forestry.
My run today I headed out at 3pm and squeezed up to Bracklin Bridge and the Scout Pool just before it got dark - the same route as from my first set of photo's above.  I just had to head out as it had been sleeting most of the day down in Callander and knew that higher up I might be able to capture some Christmas scenes.  Alas with sunset half and hour into the run the light wasn't really sufficient for great photo's.  I ran back through heavy snow falling which was wonderful.
View from Bracklin Bridge

The snow and storm felled trees on the forest trail beyond Bracklin Falls had an errie Narnia quality.

Out from the forest and into the snow storm

Heading down Bracklin Road I pass example of impromptu ditch parking!

I saw this view and had to skid in the snow to a stop to capture it.  Christmas lights of Callander.
I've been slowing ramping up my mileage and distance of runs this month by still keeping the weekly mileage relatively low - average mid thirties each week and run at a easy pace for all my runs and seeing steady gains in fitness, for instance in the 9 days between the first Bracklin Falls loop at the start of this post to the one today my efficiency according to my HR monitor has improved 5%.  I am noticing that my HR for a given pace has dropped this week which is really encouraging sign that I'm regaining the fitness I lost during the month of November when I took it very easy (just 54 miles ran in November, while 106 miles already in the first three weeks December.)

Festive greetings to all!