Base-building for a half marathon/marathon

I need once again to re-build my aerobic base.   Last year, I enjoyed a year free of ill-health, and after averaging a little over 40 miles of predominantly low aerobic training each week in the spring and summer, was pleased to run half marathon in 101:50.  By mid-summer it appeared that I was mainly limited by lack of strength rather than aerobic fitness.  Therefore, following the half-marathon, I began regular resistance sessions: three sessions per week in which the major focus was on 5 sets of 5 squats with the goal of building up my 5 RM to at least 150% of body weight.  Although I did not know it at the time, Alberto Salazar had set a very similar target for Mo Farah in preparation for the London Olympics.  Mo achieved a 5 RM of 200lbs for squats.  My program of lifting went well, and to my amazement, I built up to a 5 RM of 230 lbs over a period of four months.  Since I am a little lighter than Mo and substantially more than twice his age, I felt quite pleased with my progress.  I am afraid that I will no longer be able to blame my atrophied elderly muscles for my poor running speed.  Furthermore my creaky joints appeared to cope with the lifting well.  By the end of the year I had less arthritic pain than at any time in recent years. So I was looking forward to redirecting my focus onto running in the new year

However, shortly after I started running again, my former arthritis returned.  As on previous occasions, the problem started in my neck and left wrist, before extending to my knees, so I do not think it can be attributed directly to the impact at foot-strike when running.  I do wonder whether running led to a build-up of circulating inflammatory molecules in the blood stream that inflamed the joints, but that is speculation.  The unfortunate consequence was curtailed training and loss of fitness.  In recent weeks, my joints have settled and now only my neck is painful – though my knees still feel fragile.  But my endurance and aerobic capacity have deteriorated.  I have deferred my target of a sub-100 minute half marathon in the spring to the autumn.

So once again I am facing the cardinal question: what is the best training strategy for base-building?  For an endurance runner, a sound base has two key components: resilience of the connective tissues (ligaments, tendons, bones, fascia) and ability to utilise fuel efficiently.   The simple rule of thumb for building up resilient connective tissues is a gradual increase in volume and intensity of training over a sustained period, though there is a paucity of detailed information about this topic.   On the other hand, there is abundant information about the topic of improving the efficiency of fuel utilization, but some crucial issues remain a topic of debate.

The major determinant of endurance running performance is the maximum pace that can be sustained without accumulating appreciable lactic acid.  Loosely speaking, that is the pace at lactate threshold.  The problem with this terminology is that there is no precise threshold. Although lactate level in the blood begins to rise fairly rapidly after a certain point, the graph of lactate concentration against pace does not show a single sharp kink between two straight lines. Instead there is an initial upward trend typically occurring at a lactate concentration above 2mMol and then a steeper up-slope beyond 4 mMol.   From the practical point of view, there are two fairly clear thresholds.  The first corresponds to maximum pace that can be sustained for several hours (provided your connective tissues have the necessary resilience, and you can avoid running out of glucose).  At this pace, the rate at which lactate is cleared from the blood matches the rate at which it is produced.  Typically this is at a lactate level of 2 mMol.  Roughly speaking, this is marathon pace.   Because blood acidity is a major influence on the urge to breathe, it also corresponds approximately to the point at which breathing becomes a noticeable effort.  Because I link my breathing rate to my step rate, I become aware that I have crossed this ‘aerobic’ threshold when I find I am more comfortable taking one breath every 4 steps rather than one breath every 6 steps. This ‘aerobic’ threshold is what Hadd refers to as the lactate threshold.

The second threshold is the pace beyond which lactate builds up to an intolerable level on a time scale measured in minutes.    I know I have crossed this ‘anaerobic’ threshold when breath rate increases to one breath every two steps – but I avoid this except in the final few hundred metres of a race (or occasionally on steep hills).     Races from 5K to HM are run at a pace somewhere between the aerobic and anaerobic thresholds, while the marathon is run at aerobic threshold.  So for the endurance runner, the success of the base building phase can best be quantified by measuring the pace at aerobic threshold, or as Hadd described it, the pace at lactate threshold.

Capillaries and VEGF

To re-iterate the key point, the late threshold is the point at which the rate of removal of lactate balances the rate of generation of lactate.   Therefore, a major goal of base-building is reducing the rate of generation of lactate.  Since no lactate is produced when fuel is metabolised in the presence of sufficient oxygen, the first requirement is delivery of a copious supply of oxygen to the muscle.  This requires enhancement of cardiac output and the development of capillaries in the muscle.  Both of these developments will be enhanced by running at a pace that is adequate to place the heart and muscles under some stress, but not too much.  The production of various growth factors, such as Vascular Endothelial Growth Factor (VEGF) that is responsible for stimulating the development of new capillaries, is promoted by a shortage of oxygen, so a degree of oxygen deprivation is required to maximise the development of capillaries.   The first major challenge is determining just where this ‘goldilocks’ level of stress occurs.    The answer is still a  matter of controversy, but before attempting to answer it, we need to consider several more issues.

Oxidative enzymes in mitochondria

Maximising power output at lactate threshold also requires the development of the oxidative enzymes in mitochondria that carry out the process of burning fats or glucose, and transferring the energy released to the high energy molecule, ATP, that is the direct source of energy for muscle contraction.   The required development of oxidative enzymes will occur if the system is appropriately challenged.  Running in the aerobic zone stimulates the development of oxidative enzymes, but it is also of interest to note that High Intensity Interval Training (HIIT) also leads to increased production of mitochondrial oxidative enzymes.

Removing lactate

In order to minimise accumulation of lactate when running near the threshold, we also need to maximise the ability to remove lactate.  This is done by a process that converts lactate back to glucose in the liver.  The process of transporting lactate to the liver, conversion to glucose and then transporting it back to muscle where it can be used again as fuel, is known as the Cori cycle.  It is likely that training at a pace that generates at least a moderate level of lactate will promote development of the enzymes of the Cori cycle.   However, the Cori cycle is not a source of ‘cost-free’ energy for muscle because conversion of lactate to glucose in the liver consumes energy.  Therefore, while it is beneficial to develop the enzymes of the Cori cycle, it is far more effective to minimise the production of lactate in the first place.

So far, the various issues we have considered emphasize the importance of training at a sufficiently high intensity to produce adequate stress on the system to stimulate production of growth factors such as VEGF; enzymes such as the mitochondrial oxidative enzymes and to a lesser extent, the Cori cycle enzymes.

The recruitment of different types of muscle fibre

However, this is only one side of the equation that must be balanced.  Muscles contain slow twitch and fast twitch fibres. The slow twitch fibres are specialised to function aerobically for long periods at low intensity. The fast twitch fibres are designed to generate high power output for a relatively brief time.  The fast twitch fibres occur in two types: aerobic and anaerobic.  The anaerobic are capable of generating the power needed for explosive movement.  They can develop power on a time scale that is rapid compared with the delivery of oxygen to tissues.  For this purpose, fuel efficiency is usually less important that speed of contraction.  These fibres generate their ATP via the rapid but uneconomical conversion of glucose to lactic acid.   Thus, when the anaerobic fast twitch fibres are engaged, acidity develops rapidly.

However, the nervous system is canny in the way it recruits muscle fibres.  As the requirement for increased power output increases, fibres are recruited in the order: slow twitch, aerobic fast twitch and finally anaerobic fast twitch.  At low power, slow twitch fibres are recruited and little acidity is generated.  Training at an intensity that puts a little bit of pressure on the slow twitch fibres will lead to further development of capillaries and mitochondria, thereby providing an increase in the power output that can be generated by these fibres.

If at the other extreme, you demand that your muscles generate a high power output, the anaerobic fast twitch fibres are recruited and the muscle is flooded with lactic acid.  Acidity makes muscle contraction less efficient and ultimately, the muscles shut down. It appears that the slow twitch fibres shut down first, although do not know of direct evidence for this,.  Whether or not the slow twitch fibres shut down first, when you run at a pace that preferentially recruits the anaerobic fast twitch fibres there is little opportunity for the prolonged activity that promotes the development of mitochondrial enzymes in slow twitch fibres.

Two options for increasing oxidative capacity

An unresolved  issue of major practical importance is what happens if you do multiple brief bursts of high intensity activity, separated by recovery periods in which lactate is cleared, as in high intensity interval training.  As mentioned previously, measurement of mitochondrial oxidative enzymes before and after HIIT reveals an increase in  oxidative capacity.  The question of whether this occurs preferentially in aerobic fast twitch fibres or occurs also in slow twitch fibres is not clearly established.  Nonetheless, if you want to increase oxidative capacity, you have two options: run slowly, though the gains are likely to be most rapid near to the point where appreciable recruitment of fast twitch fibres begins; or do high intensity interval training in which the recovery intervals are sufficient to clear lactate between the effort epochs.

Developing fat utilization

However, we should not focus only on developing the capacity to metabolise glucose.  At least in longer races such as the marathon, it is essential to derive a substantial proportion of the required energy from fat, simply because the glucose supply is inadequate.   The amount of energy that can be derived from fat increases up to a certain power output, but then decreases rapidly to near zero.  The power output at which the maximum rate of fat utilization is achieved varies between individuals, though on average, in trained athletes it occurs at around 63% of VO2max.  However, the level at which maximum fat utilization occurs can  be increased by appropriate training (and perhaps also by diet).  A marathon runner will be limited to an average pace that is not much greater than the pace at which maximum fat utilization occurs.  Therefore, in preparation for a marathon, increasing the proportion of VO2max at which fat utilization is maximal, is crucial.

Although several key questions remain unanswered, the above considerations provide a basis for rational planning of base-building.  In my next post I will address the question of the optimum practical strategy.

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13 Responses to “Base-building for a half marathon/marathon”

  1. Mike Says:

    Interesting topic. Do you know whether you are a fast twitch or a slow twitch type? I understand the training needs to be different depending on which type you are – the former benefiting from interval work, the latter not.

    • canute1 Says:

      Mike, thanks for your interesting comment.

      I believe that I personally have a predominance of type 1 fibres and hence I tend to place greater emphasis on development of type 2a fibres, for example by including hill sessions. This raises the question of whether focussing on type 2A development during base building runs a risk of generating too much acidity. I will discuss this issue in some detail in my next post.

      Conversely a runner who has a higher proportion of type 2 fibres . who nonetheless wishes to run long distance events, should probably place greater emphasis on type 1 fibre development, via a higher proportion of long, relatively slow runs, during base building.

      I have little doubt that runners with a higher proportion of fast twitch can benefit from interval work, as you suggest, but I think that they have greater reason to work on developing their aerobic base

      Despite my belief that I have a predominance of slow twitch fibres, I certainly benefit greatly from interval work. However, I am sure that no matter how much interval work I might have done when younger, I would never have been a sub-4 minute miler.

  2. Ewen Says:

    You’re doing well if you can outlift Mo Farah. What’s “RM” stand for? I wonder what Mo thought when he followed the London Marathon elites through 20k at world record pace?

    I hope the arthritis doesn’t interfere too much with your base training. A friend has osteo-arthritis of the knees and recently has found relief running in the Hoka One One ‘maximal’ shoes (about twice the midsole material of other shoes) — could be worth considering.

    • Mike Says:

      RM is repetition maximum – so RM1 is the absolute maximum you can lift just once, RM5 is a weight you can lift 5 times but not 6.

    • canute1 Says:

      Ewen, reading between the lines of an interview in the Guardian, I think Mo was a bit shell-shocked by the pace in the first 20Km in London. But in fact all of the elites were a bit overwhelmed by that first half. I was not surprised that Kebede dealt with it best. I was disappointed with Wilson Kipsang. After his victories in Frankfurt in 2011, and in London last year, I thought he would emerge as a dominant ‘power’ marathoner. I suspect that he does best when he can dictate the pace.

      After our comments about Priscah Jeptoo’s style last year, she proved to us that style is not as important as fitness. Though I still fear that she might prove to be prone to injury unless she learns to control the internal rotation of her hip.

      Thanks for the suggestion regarding shoes. In fact I generally do best in moderately lightweight shoes. I think that circulating inflammatory molecules are more likely to precipitate my arthritis than the impact forces. Nonetheless I do quite a lot of training on the elliptical.

      • Ewen Says:

        Mike, thanks.

        Kebede did well to re-group after that 61:34 first half for a late attack. He was impressive. I saw today that Mo wants to go after Steve Jones’s 2:07 British Record – I think he needs 2:06 even-pace-making from the start – like Eliud Kipchoge received in the Hamburg Marathon. Jeptoo has about the most erratic style I’ve ever seen in an elite marathoner – I’d be surprised if she didn’t suffer injury setbacks in the future.

  3. Danny Says:

    Have you tried a strict vegetarian diet for relieving your arthitis? Could be worth a try. If you’re interested, here is some more info:

    http://drmcdougall.com/med_hot_arthritis_diet.html
    http://scholar.google.nl/scholar?q=vegetarian+diet+for+rheumatoid+arthritis

    • canute1 Says:

      Danny

      Thanks for the suggestion. No I haven’t tried a strict vegetarian diet. I agree that diet is very important for health. It seems to me that there are clear answers about a few things, including the value of low glycemic index carbohydrates such as in vegetables, but when it comes to strict vegetarianism I am not convinced by the evidence. I note that Dr McDougall considers that omega-3 fatty acids might be harmful in the long term. Hitherto I have considered them helpful in the short term and I also believe they have beneficial affects on other body tissues, so I eat quite a lot of fish. After reading Dr McDougall I will look into the immune system effects of omega -3 once again.

  4. Robert Osfield Says:

    Sorry to hear that all your good work in building strength has been undermined by arthritis. I don’t have any personal insights into arthritis to pass on, but I found the book “Perfect Health Diet” and associated website a really interesting exploration of food and health. On their website they have a page on arthritis, while may well know more about the topic than they do, there is chance the discussion might provide a useful perspective:

    http://perfecthealthdiet.com/category/disease/arthritis/

    I am still getting my head around all the information in the book, it’s rather dry and technical – very much the work of two scientists, my wife’s now read the book twice and taken lots of notes on second reading. We are now introducing a range of their suggested changes to out daily diet.

    The easy part is enjoying healthy fats, the harder part is cutting out wheat and similar products. We haven’t been able to vanquish wheat entirely from our diet though, pasta, bread and cakes are such an easy and quick component of meals. The biggest struggle is migrating our children though, so rather than avoiding wheat products completely we are slowly phasing in more healthy carbs so we rely less on the wheat products.

    For my own athletic performance I’m keen to eat more healthily to aid recovery, and specifically want to improve my fat burning capabilities. Having looked at the fitness results of a Scottish ultra runner that has adopt a lower carb paleo style diet, as well as evidence from other athletes I’m convinced the single most important factor to fat metabolism is diet, and an order of magnitude more important than the nature of training. If you want proof that fitness results can turn into race results, this weekend the runner ran a 1 hour PB in the Fling this weekend, over 10% quicker than her previous best. Part of this improvement is down to training changes, but I don’t believe these are significant enough changes to see such a huge improvement on their own.

    Another way of looking at the important of diet simply consider the case of untrained person who is on a ketogenic diet. If they start training then at anything below lactate threshold the vast majority of their energy will comes from fats. Compare them to trained person on typical modern western diet that is high in carbs we’d expect to see figures around 32% of energy coming from fat at around 63% of VO2Max. No amount of training is suddenly change the high carb athlete into someone who can use fat for 90% of their energy needs, but any amount of training will enable the untrained ketogenic person to improve their VO2Max and speeds their throughout their HR range whilst still working at high fat utilization.

    Once a ketogenic person is as trained as their high carb equivalents the only area where I expect we’ll see compromises in their potential will be running at VO2Max. Everything below LT we’ll see far, far greater fat utilization and with it less oxidative stress.

    There is also the possibility of training low carb and racing with moderate carb, a bit like training at high altitude and racing at low altitude. A low carb athlete will typically be more insulin sensitive and with it be able to consume carbs and get them into the muscles more efficiently without needing such high insulin levels. With lower insulin levels we’ll see less suppression of fat metabolism. If this is correct then potentially we could see improvements in performance in long duration events without the compromise with short duration high intensity work.

  5. canute1 Says:

    Robert,
    Thanks for those comments and for the link to the Perfect Health Diet page on arthritis. As you imply, the topic is complex and it is not easy to reach simple conclusions. I was interested also to read on the same page about the inconsistency of the evidence regarding omega-3 and cancer. It seems that the safest conclusion is to aim for ‘balance’ – but the point of ‘balance’ between different items if diet is not determined easily. I still eat quite lot of fish, probably more than a pound a week. On the whole I think this is beneficial, but in light of the mixed evidence regarding omega-3, I am reminded of the need to avoid excess.

    I was also interested to hear that Caroline McKay achieved a substantial PB in the Fling on Saturday, possibly as a consequence of her paleo diet. I have read quite strong arguments both for and against the paleo diet and at this stage I do not have a strong opinion. I am nonetheless quite impressed by the evidence for improved ability to metabolise fats when running in the mid to upper aerobic zone.

    • Robert Osfield Says:

      Hi Canute,

      The Perfect Health Diet (PHD) book goes into detail about the importance of various fats. Their book suggests that it’s the balance Polyunsaturated fats should not be consumed in high quantities and that one should balance Omega-3 and Omega-6 consumption.

      Modern western diets dominated by vegetable/seed oils are are very high in Omega-6 but low in Omega-3’s. High Omega-6 consumption is linked to various illnesses and higher mortality rate so it’s important to keep it in moderation. The PHD recommendation is removal all high Omega-6 sources from your diet, so no sunflower oil and general vegetable oils, as you get enough Omega-6 from other healthier dietary sources. They suggest eating fish several times a week to get healthy levels of Omega-3’s but don’t suggest supplementing beyond this.

      From your description of eating fish each week I would guess your Omega-3 levels will be fine. Your Omega-6 levels may too high though and causing problems, it’s the balance that is important.

      The PHD book also goes into great length looking at problems introduced by wheat, other seed and legumes consumption. It could well be the toxity and anti-nutrient aspects of these foods may be a factor in Arthritis.

      I’ve also currently reading “Art and Science of Low Carbohydrate Living” and have already read “Art and Science of Low Carbohydrate Performance”. One of the areas these book put forward is that low Carbohydrate diets reduce inflammation due to lower ROS production. It could be that a low Carb diet is by nature one free of refined sugars, wheat and similar products so perhaps part of the benefit in lower inflammation is down to cutting these from the diet rather than entirely due to lower Carb consumption.

      Given you want to address you Arthritis and increase fat metabolism and these books together suggest both might be helped by reducing Carbohydrate consumption, especially of wheat products, and avoiding high Omega-6 sources.

      As for paleo diets, I don’t believe the “paleo” principle is entirely sound, but does have some merit as long as you don’t take the principle too far. For endurance performance I feel that the lower carb aspect of the paleo style diets is one of the most important aspects that can be taken advantage of without following a “paleo” diet. Looking at various bits of evidence it also looks to me like avoiding seed oils and seed based foods such as breads/cakes will be advantage for general health and with it the capacity to recovery more quickly from workouts. Again the paleo diets achieve avoid these foods as well.

      Diet is such a huge topic so it’s really wrong to just pull out a few sound bites…

  6. EternalFury Says:

    For my current marathon training cycle, I have run all of my key runs in a fasted state. My hope is that it will teach my body to rely on fat more.
    All I can tell you right now is that it made my key runs very difficult. I can hold my target paces, but it definitely takes a lot out of me.

    I hope it pays off when the day comes and I supply myself with a continuous flow of carbs.

    • canute1 Says:

      EF, thanks.
      I think that the question of diet has been undervalued by most runners for many years. A few ‘cranks’ have focussed on supplements with only little evidence of benefit, while the ‘call a spade a spade’ guys have focussed mainly on training. But there are a lot of interesting ideas around at present about the way to adjust intake of carbs and fats to optimise running. I am watching with great interest as various people I know are experimenting with these ideas. I will be very interested to hear how your marathon goes. Good luck.

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