Gazelles v gliders: Mirinda Carfrae v Chrissie Wellington

As described in a recent post, my attempt to recover some of the speed of my youth by engaging in a lifting program to re-build my leg strength was only partially successful.  I exceeded my expectations regarding gains in strength, but so far this has not been translated into increased speed.  Unfortunately a recurrence of arthritis has confounded my immediate hopes, and at the moment I am more concerned about re-building my aerobic base.  However a recent discussion of the merits of gazelles v gliders on the Fetch efficient running thread has prompted me to re-examine the issue of my loss of speed.

The most striking thing about the change in my running style as I have grown older is the fact that my stride length has shortened.  Now, whenever I try to increase pace, my cadence automatically increases, often going well above 200 steps per minute even at a modest pace. While many recreational runners might benefit from an increase in cadence, at least up to 180-190 steps/min, I am fairly sure that in my case, the increase in cadence reflects reduced ability to get airborne, leading to a stunted stride.  I had attributed this to lack of strength but maybe strength wasn’t the main problem.

The gazelles v striders comparison provides food for thought.  Here is a good illustration (though I do not agree with all of the comments by the commentator).   The crucial difference between gazelles and gliders is that gliders do not produce as much elevation of the body on each step as gazelles. Because they produce less elevation than gazelles, their stride is shorter and they employ a higher cadence.  While I am not sure that even my mother would have ever described me as a gazelle, there is little doubt that I have become a glider as I have aged.   This is what I have been trying to correct.  However, this video clip provides at least some grounds for questioning the need to overcome my tendency to be a glider.   As the video illustrates, Chrissie Wellington, without doubt the greatest female triathlete ever, is a glider.    In the video, Chrissie’s gliding is compared with the style of one of the most elegant triathlete gazelles, Mirinda Carfrae.

The costs of gliding

Could it be that gliding is efficient?  It is tempting to think that reducing elevation costs must be more efficient, but this would be far too simplistic.  When considering efficiency, we need to consider the three major energy costs of running:

1)            Overcoming braking.  Provided a glider increases cadence to ensure that time on the ground does not increase, the braking cost per step will be the same for both but the cost per  mile will be  greater for the glider because there are more steps per mile.

2)            Limb repositioning costs: these increase with cadence and will be higher for the glider

3)            Elevation costs:  Although the video commentary  incorrectly states there are no elevation costs, in fact elevation of the centre of mass occurs before lift- off as a result of extension of hip, knee and ankle during the late stage of stance.   Furthermore due to the higher cadence, the saving in elevation cost per step is partially offset by the greater number of steps per mile.  However, the elevation cost per mile will nonetheless be somewhat lower for a glider because elevation cost increases as the square of airborne time, so the saving in elevation cost per step is relatively greater than the extra cost due to more steps per mile.

In estimating the total cost, we need to balance the three variables: braking and limb repositioning costs are greater for the glider, but elevation costs are less.  At higher speeds, repositioning costs become the dominant cost and there is no doubt that at high speed (e.g. faster than 7 min/mile) gazelles are more efficient.  At intermediate speeds (7min/mile-10 min/mile) braking costs and elevation costs are both quite appreciable and at such paces too, gazelles are almost certainly more efficient.  At very low speeds (slower than 10 min/mile) braking cost become relatively small because the leg is never far from vertical and therefore the horizontal ground reaction force that produces braking is always low.  At such paces the major goal should be minimising elevation costs.  So on balance, I think it is only at very slow paces that gliders might be more efficient than gazelles.

So why is Chrissie Wellington a glider?   I do not know, but wonder whether it might be an unconscious attempt to decrease the risk of injury when tired in the late stage of an ironman.  With regard to injury, the issue is the relative risk of a larger number of smaller impacts for the glider compared with fewer larger impacts for the gazelle.  While the phenomenon of repetitive strain injury demonstrates that repeated small impacts can be damaging, I suspect that size of the impacts plays an even bigger role in damage.  Therefore, I am inclined to think that for a tired runner, (either in the late stages of an ultra or an ironman) the risks will be lower for the glider.

Overall, there is little doubt that the gazelle style is better for medium paced and faster running, but there is reason to debate whether or not the glider style might be beneficial for tired, slow runners. I am still eager to become as much like a  gazelle as my aging limbs will allow.  While I can no longer blame lack of strength, I wonder if maybe lesser ability to capture elastic energy at foot fall is the cause of my gliding.   In a future post I will describe my plans for the attempt to recover elasticity.   But in the short term, my focus is on re-building my aerobic base, and that is what my next post will address.

Finally, it is noteworthy that on the two occasions when Chrissie Wellington and Mirinda Carfrae went head-to-head in the world ironman championship (at Kona in 2009 and 2011), on each occasion Wellington won the overall event but on both occasions Carfrae ran the faster marathon. In my opinion Wellington is the greatest female triathlete ever but Carfrae is the more efficient, and faster, marathon runner.

Added note (4^th May 2013)

In his comments below, Robert had pointed out that I have not provided adequate justification for my claims about the energy costs.   My claims are based largely on calculations based on applying Newton’s equations of motion to the simplified model of running described in my posts in January and February 2012.    At a pace of 4 m/sec, (which is close to that of Carfrae and Wellington in the world ironman championship in 2011) the calculations demonstrate that the combined cost of elevation and braking is 6% greater for a Glider than for a Gazelle, assuming that that the Glider has an increased cadence sufficient to produce a similar time on stance.  Observations suggest that Gliders do increase cadence to maintain a similar time on stance, and furthermore, if a Glider did not have increased cadence they would be even less efficient because the longer time on stance would produce an even greater increase in braking costs (as indicated by my post of February 2012).

The crucial questions is whether or not the simplifications I used in performing these calculations lead to serious errors. There are two respects in which the simplifications might lead to error.  First, I assumed a sinusoidal shape for the variation of ground reaction force with time.   Variations in the shape of this curve introduce small changes to the results of the calculations, but in the absence of force plate data for each runner, I cannot do a more precise calculation.  However, the error due to this simplification is likely to be small.

The other potential source of error is that my calculations are for the total energy expended on elevation and overcoming braking. I have not subtracted the energy saving expected via elastic recoil.  If a runner maintains greater tension in the leg muscles, as recommended in the BK running style, it is possible to recover a greater proportion of the required energy via elastic recoil.  I cannot exclude the possibility that a Glider might maintain greater tension in the leg muscles, but think that in general this is unlikely as increased tension in the leg muscles results in a greater rate of rise in ground reaction forces and potentially increases the risk of injury.  The advocates of the BK style recommend thorough preparation using plyometrics before attempting this.  I think that increasing leg muscle tension would not be a good strategy for a tired ultra runner.  Thus I doubt that Gliders make greater savings via elastic recoil than Gazelles. I suspect that the opposite might be the case, though this is speculation.  However even if equal efficiency of recovery of energy via elastic recoil is assumed, the Glider incurs a 6% greater cost for elevation and braking than the Gazelle.

Also, it should be noted that my calculations do not include limb repositioning costs. These costs are almost certainly higher for the Glider because repositioning cost increases with cadence (as discussed in my post in April 2012) and furthermore, the trajectory of the foot of a Gazelle results in a shorter lever arm of the swinging leg, further increasing efficiency.

On balance, I think it is likely that my calculations provide a fairly realistic estimate of the relative costs of elevation and braking for the two styles.

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.

Is prolonged vigorous training bad for your health?

In a comment on my recent post, Steve asked what I thought of James O’Keefe’s recent TED lecture ‘Run for Your Life! At a comfortable pace, and not too far’.  The short response is that I agree with O’Keefe’s conclusion that if your goal is to maximise the length of your life, the best strategy is probably to exercise regularly at moderate intensity.  I also agree with a few of the specific points that O’Keefe makes, though I would not advance them in such a self-assured manner, because much of the evidence is incomplete.  In fact I found his manner of presentation more fitting for a snake oil merchant than a scientist.   He has presented a somewhat less dramatised version of the evidence in an article in the reputable Mayo Clinic Proceedings, though even that article contains at least one misleading inaccuracy.

There are several important respects in which his claims are misleading or simply wrong.   Other bloggers (for example Michael Accad, Lawrence Creswell and Alex Hutchinson) have posted thoughtful articles that subject his arguments to evidence-based scrutiny.   My purpose in this post is not point out the inadequacies of O’Keefe’s arguments, but rather to put forward my own thoughts of the evidence suggesting that training above a certain volume and/or intensity might be harmful.

The first crucial point that must be made is that the evidence on mortality shows that the more your train and the more vigorously you train, the greater your life expectancy, though the data does suggest that there are diminishing returns from a very large amount of vigorous training. The data present by Wen and colleagues in their article in the Lancet based on longitudinal data from 400,000 individuals, show first of all that people who exercise vigorously have a greater reduction in mortality rate than those who exercise moderately.  However, among those who exercise vigorously, the rate of reduction in mortality risk with increasing minutes per day spent exercising begins to flatten beyond 50 minutes per day.  However contrary to the message given by O’Keefe in his TED lecture, and also contrary to what O’Keefe states in his article in the Mayo Clinic Proceedings, Wen’s data does not show that the benefit peaks at 50-60 minutes per day.  In fact Wen made it very clear in a response to a question by O’Keefe published in the Lancet in March 2012 that the available data reveal that the mortality was even lower among those exercising vigorously for 120 minutes per day, but of course the numbers of individuals exercising vigorously for 120 minutes per day is small.  Wen quite sensibly refrained from extending the mortality graph beyond 60 minutes per day in his original article simply because the data is less reliable when based on a small number of individuals.

O’Keefe’s misrepresentation of Wen’s data in the TED talk, despite the fact that Wen had explicitly informed O’Keefe of the true situation about 8 months before the TED talk, is perhaps the most serious reason to distrust O’Keefe.  However, just because O’Keefe appears to be untrustworthy does not mean that all his conclusions are wrong.

So what does the data really show us?

In my opinion, the following conclusions can be drawn with moderate confidence:

1)      Exercise is associated with increased life expectancy, and at least up to 50-60 minutes of vigorous exercise per day, the more exercise you do, the lower the mortality rate.  The limited available data indicates that those exercising vigorously for 120 min per day have an even lower mortality rate, but the numbers are too small to allow confident conclusions.

2)      Prolonged vigorous exercise does produce changes in the heart, including an increase in the diameter of the ventricles and thickness of the ventricular walls.  I reviewed this evidence in detail in my post on Micah True.

3)      The increases in ventricular diameter and thickness are probably adaptive, in the sense that they make it possible for the heart to pump a larger volume of blood more forcefully to meet the requirement of a massive increase in cardiac output when running.  In athletes, unlike in individuals with overt heart disease, hypertrophy is usually accompanied by a potentially healthy increase in capillary density.  However, in at least some individuals, the remodelling of the heart is associated with disruption of cardiac rhythm.  In particular, there is strong evidence that prolonged endurance training increases the risk of atrial fibrillation (as reviewed in my post in June 2010 and several subsequent posts).  In those posts I also reviewed the evidence for increase in other rhythm disturbances, including potentially more dangerous disturbances arising in the ventricles

4)      Rhythm disturbances such as atrial fibrillation increase the risk of stroke, at least in non-athletes.   The question of whether atrial fibrillation produces an appreciable increase in the risk of stroke in athletes remains unanswered, though there are documented individual cases of adverse outcomes.  For example, in a 9 year follow-up study of 30 athletes with atrial fibrillation, Hoogsteen and colleagues found that 3 (10%) had died; 15 (50%) exhibited continuing paroxysmal atrial fibrillation; permanent atrial fibrillation emerged in 5 (17%) ; and 7 (23%) of showed no further atrial fibrillation.  Of the three deaths during the follow-up period, one was a sudden death during a race and is likely to have been due to a heart rhythm disturbance.  The other two were attributed to strokes.  Although Hoogsteen re-assuringly concludes that these deaths were not directly attributable to atrial fibrillation, the outcome is disconcerting.

5)       In at least some cases, especially males who have run many marathons over a period of many years, there is evidence of increased calcification of the coronary arteries, potentially predisposing to heart attack (reviewed in my post of Jan 2012).

How should we react to this rather confusing mass of evidence?    If your goal is simply to live a long and healthy life, the simple answer is to exercise frequently at a moderate intensity.  This will produce a substantial increase in your life expectancy with little risk of adverse consequences.  However, if you enjoy running, and in particular enjoy the thrill of running fast or the challenge of racing, the situation is different.  From a statistical point of view, if you train vigorously for an hour a day, your life expectancy will be much greater than if you spent that time watching TV and perhaps greater even than the life expectancy of a the health-conscious runner who runs only at moderate intensity, but the data warrants more detailed inspection.

It is encouraging that the data from Wen’s study showed lower mortality risk for the small number of individuals exercising vigorously for 120 minutes per day.  It is tempting to conclude that the additional health benefits from such training might outweigh the increased risk of adverse effects such as cardiac rhythm disturbances. However, we should hesitate before concluding that 120 minute per day of vigorous training causes the observed reduction in mortality.  Once we are dealing with a small number of exceptional individuals, it is necessary to be very cautious in assuming the direction of the cause that generates the statistical correlation.  It might be that only individuals with an extraordinarily robust natural constitution can sustain this level of training.  Whatever we might conclude regarding overall mortality associated with extensive vigorous training, the inescapable conclusion is that there is a real risk of serious adverse cardiac events in a minority of individuals.

The crucial question

If we wish to continue to train extensively and vigorously, the crucial question is ‘can we do anything to ensure that we are not in the minority who suffer a serious adverse event?’  Unfortunately, the evidence is not good enough to allow absolute assurance of safety.  However I think there is a growing body of evidence that helps us to avoid the circumstances that are most risky, and as a second line of defence, there are ways in which we might identify the onset of potentially serious disturbances and deal with them before they become dangerous.

First of all, what do we know about the circumstances that increase risk?  For about 24-48 hours after a marathon, blood levels of troponin, which is a marker of trauma to heart muscle fibres, are elevated, and the strength of ventricular contraction is weaker.  Almost certainly the heart is more vulnerable during this period.  However, the evidence also suggests that these signs of trauma are transient.  The heart recovers.  If it is true that that the benefits of training reflect repair of transient trauma, the heart might be even stronger afterwards.  So there is a very sensible way of increasing the odds in ones favour: make sure that you allow adequate recovery after a strenuous event such as a marathon.  My own belief is that full recovery from a marathon raced to the limits of one’s ability, takes a period of several months.

Chris Mcdougall, who made Micah True the central figure in his book ‘Born to Run’, reports that True had done a six hour run in the Gila desert the day before he died.  Anecdotal evidence suggests that True had not taken his dog with him on the fateful last run because the dog’s paws were sore from the previous day’s run.   If indeed McDougal’s report is correct, I think that a plausible explanation of why True died during a mere 12 mile run is that he had not recovered adequately from a strenuous run the previous day; a run that might well have been expected to have produced transient damage to his heart.  This is of course mere speculation based on anecdote.  Other theories such as the possibility that he suffered from Chagas disease, which is endemic in New Mexico, must also be considered.  But the point that I wish to illustrate is that if you enjoy running marathons or more extreme endurance running, you are not a hapless pawn at the mercy of statistical prediction.  You can alter the odds and you are less likely to be among the minority with serious adverse outcome if you are well attuned to the need for adequate recovery.

Chronic inflammation

As Dr O’Keefe emphasized in his TED talk, the likely mechanism by which extensive vigorous training might damage the heart is chronic inflammation.  So perhaps the most important thing to seek is a way of identifying the development of chronic inflammation at an early stage, and alleviating it.  Our current understanding of chronic inflammation remains inadequate, but there is a growing body of useful information.

Chronic inflammation is also likely to be the mechanism responsible for the over-training syndrome, discussed in my post in March 2010.   There are some promising strategies for identifying both the early stage of over-reaching, manifest as sympathetic over-activity, and the more enigmatic late stage of over-training characterised by parasympathetic over-activity.    Although the tests for over-training are still rudimentary, the availability of heart rate monitors that record the variability in intervals between heart beats (R-R variability) has opened the door to the possibility of early identification of the excessive parasympathetic activity characteristic of over-training.   However the reliability of current procedures has yet to be established adequately.  Alternatively, measurements of heart rate during exercise, such as the Lamberts and Lambert sub-maximal cycle test, are showing promise.

If over-reaching is identified in the early stage, it can be alleviated by scheduling a day or two of recovery.  The more advanced stages of over-training are much more difficult to deal with, though it is encouraging that studies of animals indicate that even quite severe chronic inflammation can resolve during a sustained period of lighter exercise.

Not only are there sound principles regarding recovery from strenuous events together with a growing body of information about early identification and alleviation of over-training, but, as a second line of defence, a heart rate monitor with the capacity to record R-R intervals might also provide advance warning of transient minor rhythm disturbances occuring long before a dramatic serious disturbance.  Unfortunately, here we get into sparsely charted waters where there is little good evidence to guide us.  Furthermore, there is a danger that artefacts arising from poor electrode contact or other interference can confound the interpretation of erratic R-R recordings.

My experience

I still remain uncertain about the cause of the erratic rhythms I had recorded in 2009 and 2010.  I am now confident that many of the oddities were due to poor electrode contact, but I am inclined to think that others, especially the sharp spikes followed by a partially compensatory pause, were likely to be premature atrial contractions.  In an elderly person, premature atrial contractions are not uncommon, but nonetheless might be a warning sign.  I was intrigued to note that on one occasion when I had become seriously dehydrated after being forced to make an unexpected long detour during a run through parched desert terrain, that the frequency of the sharp spikes was increased.  Maybe they were artefacts due to poor contact between the electrodes and my dry skin, but nonetheless I took that experience as a warning to avoid serious dehydration in future.

I am re-assured by the fact that in the past year, during which I have followed a markedly periodized training program that has nonetheless included a greater volume of training than in any recent year and produced better race performances, I have observed fewer sharp spikes in the R-R records.  While the interpretation of odd rhythms when they occur is fraught with ambiguity, the current rarity of spikes is re-assuring.  Perhaps it is a consequence of more careful planning of my training.  While my own anecdotal experiences prove very little, I think that they do provide grounds for further investigation of the potential value of a heart rate monitor with R-R recording capability as a screening tool to detect circumstances where vulnerability might be increased, or to identify oddities requiring further investigation.

In my younger days, I was a keen mountaineer.  A few months ago when in Switzerland to give a talk, I took the opportunity to spend a few days in the mountains, and was reminded of how awe-inspiring it is to climb amid snow covered peaks.  The sense of awe is all the greater when the crisp breeze chills your face and there are few sounds others than the chatter of your companions and the calls of the choughs circling in the air below you.   Viewing the mountains through the glass window of an overheated restaurant surrounded by slushy snow at the top of a cable car ride offers a pale and soggy comparison.  Mountaineering is intrinsically dangerous.  The overt dangers are probably greater than those from the most extreme endurance events.   Some of the risks are inherently unpredictable, but nonetheless, thorough knowledge, good planning, sound judgement and a small amount of highly technical equipment can do much to reduce the risks.

The comparison with running is imperfect, but the delight in executing a finely balanced move on delicate holds across a rock face, the grandeur of the summit views, and the satisfaction in knowing that you have pushed yourself to the limits of your physical and mental strength are a counterpart to the delight of running with graceful style along woodland trails and the satisfaction of racing to the limit of your physical and mental strength.  I am therefore happy to embrace the risks that are involved, but nonetheless, just as I regard equipping myself with knowledge, expertise and equipment to maximise safety is part of the satisfaction of climbing, I consider that the challenge of learning how to minimise the risks is a part of the satisfaction of running well.

Can an awesome race face fool the central governor?

As described in recent posts, over the past two years it had become increasingly clear that leg muscle atrophy has been limiting my running speed.  So for the past 8 weeks I have been lifting weights, three or four times per week to increase my leg muscle strength.  My primary focus is on barbell squats and dead-lifts.  These lifts provide a whole body work-out, though the major load is borne by the quads, the posterior chain (hams, glutes, hip adductors) and trunk muscles.  I started with the empty bar (20Kg) while learning safe technique and then progressively incremented the weight. After a warm up with light weights, I do 5 sets of 5 reps with the squats and 1 set of 5 dead lifts at my 5 rep maximum.  I am now lifting over 90 Kg, which is around 150% of my body weight, in the squats and a little more in the dead-lift.

During this period I have cut back on the amount of running to about 25-30 Km per week in order to avoid undue stress on my legs.  I find that the heavy lifting leaves my leg muscles feeling sluggish and lacking the springiness required to cope with the eccentric loading incurred during running. However, the elliptical cross-trainer demands much less little eccentric loading of the muscles; so for several weeks I have been doing high intensity interval sessions on the elliptical to maintain aerobic fitness, but I have lost some of the endurance I had built up in the summer.  I will have to re-build this in the spring

At this stage I have been pleased with the increases in strength produced by my lifting program.  While lifting 150% of body weight would be  very modest achievement for a dedicated weight-lifter, it is not bad for an elderly person with the spindly physique of a marathon runner.  I have gained about 1 Kg in body weight.  It is probable that I now have near optimal strength to weight ratio for an endurance athlete.   It is too soon to know what effect this will have on my running.  I need to do a few weeks of power lifting (with lighter weights and faster movement) and plyometrics early in the New Year to increase the speed with which I can recruit my strengthened muscle fibres  Then I will be ready to assess whether or not the increased strength has produced the anticipated increase in running speed.

Maximising muscle recruitment

The experience of lifting near maximum weight has focussed my mind on tricks for maximising muscle recruitment.  While a lot of the noisy exclamations that reverberate around a gym appear to be mainly for show, even serious lifters grunt when lifting at near maximum capacity.  Studies indicate that this produces a modest increase in the maximum lifting capacity.  In part this grunt reflects the fact that it is essential to maintain a high intra-abdominal pressure to stabilize the trunk during the lift, for both dead-lifting and squats, so expiration is performed though an almost closed glottis.  However, it is probable that some of the benefit comes from the psychological effect.

In recent years, the grunts by female tennis players, perhaps most notably Maria Sharapova, have been a bone of contention with opinions ranging from Martina Navratilova’s view that it is cheating because it disguises the potentially informative sound of the ball on the racquet, to coach Nick Bollettieri’s claim that it serves a similar torso-stabilizing purpose as the grunt of the weight-lifter.  I understand that Jimmy Connors was the one who introduced grunting into grand slam tennis, and many others including Andre Agassi, Monica Seles, and the Williams sisters have followed, but Sharapova employs it with greater dramatic effect.   The possible mechanical benefits from stabilizing the torso by forceful exhalation against a closed glottis appear to be only a minor justification for her 100 decibel shrieks.

Hyperventilation

Because I am only lifting at 5 rep maximum (about 90% of 1RM) I do not grunt.  However I have been aware  that as I prepare to begin lifting I take a couple of short deep inspirations before the final sustained deep inspiration required to maintain the intra-abdominal pressure necessary for heavy lifting.   Is this hyperventilation just a delaying manoeuvre to give me a few seconds to psyche myself up for the effort, or does it serve a physiological purpose?

In many circumstances, hyperventilation is a bad strategy.  At rest, it can produce a syndrome characterised by palpitations, dizziness, and tingling sensations.  In susceptible individuals, it triggers panic.   These effects are largely due to the clearing of carbon dioxide from the blood, thereby making the blood more alkaline.   But the full array of effects produced by hyperventilation is complex, and includes many ‘central command’ effects.  Some of these are reflect brain-stem reflexes, while others reflect the effects of low carbon dioxide levels on brain regions including hypothalamus, hippocampus, other limbic areas and locus coeruleus that control the autonomic nervous system.  Hyperventilation produces a rise in heart rate; increased cardiac output and increased blood flow to limb muscles.

Lifting near maximal weight demands tensioning of limb and trunk musculature, and I suspect that my spontaneous hyperventilation as I prepare to lift is an unintentional ‘trick’ to generate the required tension.  In effect, the surge of alkaline blood encourages the control systems in the brain to release the brakes and allow maximal recruitment of muscles.

I have also noted in the past that when I wish to increase power output when doing high intensity interval sessions on the elliptical cross trainer, I automatically increase ventilation a fraction of a second before I increase power output.    It appears that when I do this that increased power is a consequence of increased depth of respiration rather than increased pace producing a passive increase in respiration.   In other words, a signal associated with increased frequency or depth of breathing promotes increased recruitment of muscles.

Tim Noakes’ concept of the central governor has been a controversial topic. Maybe it would be over-simplistic to imagine the  ‘governor’ as a miniature pilot embedded in the non-conscious recesses of one’s brain, but there are undoubtedly a number of mechanism mediated by blood-borne chemical messengers and the autonomic nervous system which together act to adjust muscle recruitment.  Furthermore, these mechanism appear to by modulated to allow for anticipated future demand.  For practical purposes, I find it helpful to regard this set of automatic control mechanisms as a prudent governor which generally acts to optimise my performance, but occasionally needs cajoling to relax when it becomes over-conservative.  In some circumstances, hyperventilation can be a useful trick that encourages the ‘governor’ to increase cardiac output and muscle recruitment.

Breathing while running

But what about when running?  Here we encounter conflicting demands.  As Usain Bolt cruised to Olympic gold in Beijing he exuded a sense of relaxed power.   There was no sign of needless muscle tension nor hyperventilation.  Sprinters usually hold their breath from the set position and typically exhale only once during the first thirty metres.   For long distance runners, deep breathing from the diaphragm is required.   I allow my breathing rate to adjust itself according to demand, but  usually find that I am employing a 3-3 pattern (three steps during inhalation; three during exhalation, corresponding to a breathing rate of around 30/min) when running in the mid-aerobic zone, and 2-2 pattern when near the second ventilatory threshold (10K pace).  However in the final sprint I usually increase automatically to 1-1.  When breathing simply follows demand it should not be described as hyperventilation, which by definition is breathing in excess of oxygen requirements.

Can hyperventilation be useful for a runner?

However other experiences leave me wondering whether there are times when a runner can use hyperventilation to advantage.  In the Robin Hood half marathon in September, I had been struggling to raise the tempo of my running throughout most of the second half of the race.  With 3 km to run, my conscious brain was still fruitlessly commanding my legs to go faster, but my non-conscious brain was countermanding the order.  The first photo (taken from my blog describing the race) illustrates the fruitless struggle between conscious will and leaden legs.

But then with 100m to go, I resorted to the hyperventilation trick.  I deliberately increased breathing rate to a 1-1 pattern to jump-start an all-out sprint.  I was subsequently amused and a little dismayed when I saw the second photo.  The facial contortion and tension in the accessory muscles of inspiration in my neck create an impression of needless waste of energy.  Almost certainly the amount of tension was somewhat excessive, but the crucial fact was that I felt energized and powerful.  Despite my grotesque facial appearance, the ‘central governor’ had relaxed its leaden grip and released the shackles from my ankles.

The final sprint

This trick wouldn’t have worked with 3 Km to go.  At that stage, the governor’s  determination to conserve my meagre reserve of energy would not have been so easily brushed aside.  But with 100m to go, there was no longer any need for such tight control.  What was needed was a stimulus to trigger a gear shift.  The combined physiological effects of increase cardiac output and decreased peripheral vascular resistance produced by the hyperventilation created a surge of blood to the muscles that provided the required trigger.   In the overall strategy of racing a half marathon or marathon, the final 100m has a trivial impact on the time recorded, but it is satisfying to claim a final few scalps and move up the finishing order.

Hopping: Paula Radcliffe, Mo Farah and me

On Saturday, I repeated the hopping test. I consider the distance covered in 5 hops on one leg is a good test of running-specific strength.  Seb Coe used to do a similar test.  He could cover 25 metres on 8 hops, but as a cronky old-timer my target is much more modest.  Before the episode of arthritis that afflicted me in January 2010, I could cover 9.71 m in five hops on the left leg and 9.24 m on the right.  The discrepancy between legs reflected the fact that previous episodes of arthritis had affected my right knee more than my left.  In contrast, the episode in early 2010 attacked my left knee (in addition to my left wrist and neck).  The arthritic pain lingered through most of 2010, causing me to minimise forces transmitted through the knee.  By December 2010,  I had lost about 20% of my hoping strength, and now my left leg was weaker than my right; I achieved 7.39 m on the left and 7.44 on the right.  My attempts to remedy this loss by plyometrics in early 2011 were thwarted by recurrence of pain in the left knee.

Several other health problems also interfered with training but by late summer 2011, I was once again able to train regularly.  As described in recent posts, in the following 11 months I trained regularly, unhindered by illness or injury, and my aerobic fitness improved greatly.  But by July 2012, I was stuck in a rut.  I found it very difficult to maintain a pace of 5 min/Km for more than a few Km despite evidence of good aerobic fitness.  It appeared that I had such small reserves of muscle strength that even at 5 min/mile pace I was recruiting not only all my type 1 fibres but also most of my type 2 fibres.  Not surprisingly, I could not maintain such a pace for more than a few Km.  A repetition of the hopping test in July confirmed that lack of muscle power was the problem. I covered 7.45 m on the left and 7.77 m on the right.  Eleven months of mainly aerobic training, with a modest amount of hill work and interval training, had produced only a 2% improvement in hopping.

At that stage, I commenced a ‘quick and dirty’ program of weight lifting – ‘dirty’ in the sense that I built up the load quickly, rather than painstakingly developing by the technique and basic all round strength necessary for safe lifting at near maximal capacity.   But at that stage, there would be no prospect of going to maximum loading before the RH half marathon in September so I spent a few weeks building rapidly to moderate loads before returning to predominantly aerobic training for the final few weeks.   In the event, the strategy worked. I ran a reasonably good half-marathon, and then a few weeks later, a satisfying 5K.

Because maximal-effort hopping presents significant risk of musculo-skeletal injury for an elderly person, I perform the test sparingly.  Nonetheless, by last Saturday it was time to repeat it, both to confirm that my training since July had indeed produced an increase in hopping performance, and to provide a base-line for assessing future improvement.   I achieved 8.65 m on the left and 8.46m on the right.  Thus in the past 3 months, I had improved a further 8% , and have now recovered about half of the strength that I had lost following the arthritis in 2010.   In contrast to the 2% improvement produced by 11 months aerobic training including some hills and intervals, 3 months that included a mixture of weights, drills and further aerobic training produced an 8% improvement.   This evidence of increased hopping distance accompanying the improved running performance provided addtional confirmation of the conclusion that I was stuck in a rut in July on account of inadequate muscle power to utilise my aerobic capacity.  The fact that my hopping performance is now about halfway back to where it was at the beginning of 2010 indicates that there is scope for further improvement in hopping capacity, and hopefully, also in running speed. Nonetheless, the question of whether weight training is useful for distance runners remains a matter of controversy

What do the Kenyans do?

In a balanced review of the issues, Pete Pfitzinger remarks with a touch of irony ‘the Kenyans are so secretive in their iron-pumping that no one has ever seen them lift. Travel to Ethiopia, and you will see an equally impressive absence of muscle-building.’  This observation is indeed reason to consider the issues carefully before embarking on a time consuming and demanding weight lifting program.  However, Pfitzinger’s observation must be set against the evidence that very demanding resistance training is not unknown in Kenya.  The fascinating video of the BOSS Baltic team including Asbel Kiprop (1500m gold medallist in Beijing and world champion in 2011) training in the rain at Iten stadium in November 2011 reveals an extremely demanding session that included dragging car tyres around a water-logged track; running against a restraining waist band; and intense plyometric jumps over a series of hurdles.

The experiment with N=1

While there is abundant scientific evidence that combining weight lifting with aerobic training improves running-specific factors such as running efficiency and time to exhaustion when running in the upper aerobic zone, there is no large study that has demonstrated that weight training improves racing performance at any distance from 5K to marathon.  However each athlete is an individual and must weigh up the evidence of what is likely to be helpful for him or her.  There is an abundance of anecdotal evidence regarding the benefits of weight training for individual runners.  How closely do the anecdotes match my own situation?

Paula Radcliffe

Her fourth place in the 10,000m final in Sydney in 2000 demonstrated yet again that Paula lacked the strength in the final lap required for victory at the highest level of competition.   In an attempt to define the problem, Irish physiotherapist, Gerard Hartmann asked Paula to do 20 hops up and down from a 16 inch high box as fast as she could. In contrast to Kelly Holmes who had had achieved 20 hops on and off the same box in 12.5 seconds, Paula took 27 seconds on her first attempt. This led Hartmann to devise a program of plyometric exercises and heavy weight sessions. In 2002, Paula won her first senior world title (long cross country in Ostend, Belgium) and also won her debut marathon in London, in a time only 8 seconds slower than Catherine Ndereba’s world record of 2:18:47.  Later that year, in Chicago, she staked her claim to ownership of the world record by slicing 89 seconds off Nderaba’s best.  The following year, in London in April she recorded the awe-inspiring time 2:15:25, a mark that remains unchallenged.

In my post six months ago following Mary Kietany’s victory in the London marathon in April, in which she shaved a few seconds of Katherine Ndereba’s best, I speculated that a new generation of Kenyan women might be about to mount a serious challenge to Paula’s record.  I should also have added Ethiopian woman to the field of contenders as Tiki Gelana had recorded 2:18:58 in Rotterdam a week before Kietany’s win in London, and Aselfach Mergia had broken the 2:20 mark earlier in the year in Dubai.  Indeed there was no reason to limit my horizon to Africa as the second fastest female marathon runner of all time is Liliaya Shobukove of Russia with a time of 2:18:20 in Chicago in 2011, while about a dozen other woman including Mizuki Noguchi, Irina Mitenko and Deena Kastor have recorded times under the 2:20 mark.   However, so far there has been no sign pointing to an imminent quantum leap in women’s marathoning.  Since April, the only woman to get anywhere near 2:20 was Aberu Kebede with her winning time of 2:20:30 in Berlin in September.  Paula’s record from 2003 looks as secure as ever.

As I watched the video of the BOSS team training in the rain soaked stadium in Iten, I was struck by the contrast between the male athletes and the lone female athlete wearing a red top and blue trousers.  She too dragged the tyre around the track, and battled persistently against a restraining band tethered to a post, but the power of her legs paled in comparison with that of the men.  I do not know what distances she races, and wish to draw no conclusion other than noting that the video provided a graphic illustration of the major gender difference in strength, a difference that is manifest in the power of the movements that are required for running.  In my post in April I had speculated that women should less severely disadvantaged relative to men in the marathon than in shorter events because the event is largely fuelled by reserves of fat, but I think that speculation missed a crucial point. Even the marathon is an event requiring strength, a point illustrated not only by Sammy Wanjiru in Beijing but even more dramatically by Wilson Kipsang Kiprotich in London in April of this year.  His powerful surge shortly after the halfway mark crushed most of his opponents.  He tried a similar tactic in London in August.  But whether it was merely the heat of that August day or the fact that his body was beginning to fatigue after three top-level marathons within 10 months (starting with his near world record breaking win in Frankfurt in October 2011), his strength failed him in August and he faded to third place behind Stephen Kiprotich and Abel Kirui.    Nonetheless, it is clear that the men’s marathon is a test of strength as well as aerobic capacity.   I suspect that Paula stands unrivalled among female marathoners not only on account of her tremendous aerobic capacity but also on account of the strength program that Gerard Hartmann designed for her in light of her dismal hopping test performance in 2000.

However Paula’s story has a sad coda.  After dropping out of the marathon in Athens in 2004 apparently due to complications arising from treatment for a leg injury; her subsequent game but ill-starred attempt in Beijing in 2008 following a stress fracture; and then a failure to even get to the starting line in London in 2012, her Olympic dreams have been dashed.  Of course luck plays a role.  But the video of her world record breaking run in Chicago in 2002, and of her spectacular run in London the following year, reveal a runner tensing almost every muscle as she strains to drive herself onward. Perhaps the unwarranted muscle tension provides a clue to the contrast between her unrivalled performances when her body lasted the distance, and the numerous occasions when her body failed her.   I understand that Gerard Hartmann made a determined efforts to help her reduce the head bobbing that characterised her running prior to 2002, but I wonder whether she might have added an Olympic medal to her otherwise unrivalled record if she had devoted more attention to integrating her strength into a well coordinated, relaxed running style.

Mo Farah

In a press conference shortly after Mo Farah’s dominant performances in the 5000m and 10000m in London in August, Alberto Salazar described how, when Mo joined him team in Oregon 18 months earlier, he was a skinny distance runner who performed strength exercises like a 90 lb weakling.  He recognised that if Mo was to fulfil his potential and hold off the world’s best in the final lap of a 5000m race, he would need strength.  Salazar got him lifting weights alongside Galen Rupp, and the transformation of his physique was dramatic.  In Alberto’s opinion, the seven hours every fortnight spent lifting weights in the gym played a more important part in Mo’s victories in London than the 110 miles a week of aerobic training.

Thus,  anecdotal evidence regarding both Paula Radcliffe and Mo Farah indicates that in individuals in who have an identifiable deficit in strength, resistance training including the lifting of heavy weights can produce worthwhile improvements in running performance.

My plans

My goal is to run a good marathon at age 70 but the first step is to run a half-marathon in less than 100 minutes.  I am now within sight of that goal, but I think the evidence that I am limited more by lack of muscle power than by my aerobic fitness in now unequivocal.  There are several options: I could build type 2a fibres by running long hills; I could increase my strength and endurance by training in a weighted vest, just as I acquired the power required to run a marathon in under 2:30 over forty years ago by spending many days walking and climbing up mountains with a pack weighing between 30 and 40% of my bodyweight on my back; or I could lift weights.  I think that in old age, as anabolic hormone production wanes, the surge of anabolic hormones produced by brief periods of heavy lifting makes weight lifting the preferred option.

Lifting weights will develop type 2a aerobic fast twitch fibres.  While these fibres are in themselves of considerable value when running near the upper end of the aerobic zone, especially on a hilly course, the major requirement for a marathoner or half marathoner, is abundant type 1 fibres.  Gehlert’s study of cyclists who switched to program of high volume/low intensity training demonstrates that type 2a fibres can be transformed to type 1 fibres, at least in those individuals who have a predominance of type 2a fibres prior to the switch in training.  Unfortunately, the role of other factors such as one’s genetically determined predisposition towards type fibre 1 dominance in promoting or inhibiting this transformation remain a matter for speculation.

Whatever plans I make for training, it will be a unique experiment on myself.  Neither anecdotal accounts of the experiences of others such as Paula Radcliffe and Mo Farah, nor systematic studies of groups such as that conducted by Gehlert will answer the question of how I can best develop the muscle strength that I require.  However, the evidence suggests that the best strategy should include three phases: strength development; incorporation of this strength into a well coordinated relaxed running style: and finally the transformation of at least some of the type 2a fibres to type 1 fibres while I rebuild my aerobic capacity.

As outlined in a recent response to a query from Robert, my current provisional plan is as follows:

Phase 1 (8 weeks) : primary goal – strength development. The key activity will be high load, low repetition weight lifting, together with hills and drills to initiate the incorporation the additional strength into running-specific action, and a modest amount of low aerobic training to maintain my current type 1 fibres.  I anticipate increase in volume of type 2 fibres with only small loss of type 1.

Phase 2 (3-4 weeks): primary goal – incorporation of strength into running action.  I will do hills, drills and intervals to maximize incorporation of strength into a relaxed, efficient running action, with a small amount of weight lifting to maintain strength and a modest amount of low aerobic training. I will evaluate progress in a 5K time trial in January.  The anticipated main changes in muscle will be refined recruitment of fibres rather than a change in fibre composition.

Phase 3 (12 weeks): Primary goal – aerobic development.  I will do predominantly aerobic training with increase in length of runs; some weight lifting to maintain strength; drills. hills and intervals to maintain speed. The program will end with a two week taper to a half marathon in April.   I anticipate conversion of type 2a to type 1 fibres in this phase, but also hope to maintain a moderate proportion of type 2a fibres.

Ewen has picked up the gauntlet in a challenge to be the first to break100 minutes for a half-marathon in April.  My eyes remain focussed on the marathon in the long term, but in the short term, this virtual duel with a fellow spirit from the other side of the globe will add a little spice to my endeavours.

..

Resistance training for distance runners

Classically, a sprinter has the torso of an ox while a marathon runner has spindly legs and arms.  Sprinters spend a substantial time in the gym lifting weights and afterwards eat a lot of protein; marathon runners spend even longer on the road depleting their muscle glycogen and then consume carbohydrate to replace it.   When finishing a long run at a pace near to race pace, marathon runners are actually in danger of burning the protein from their own muscles.  If they work with weights it is usually using high repetitions at moderate load to build up strength endurance rather than the power which a sprinter aims to develop with fewer repetitions with much heavier weights. These distinct training patterns have proven successful, on the one hand for many sprinters and on the other hand for many endurance runners.   Clearly, the physiological needs of the sprinter, whose first requirements are muscle power and neuromuscular coordination, differ from those of the endurance runner, whose primary need is to supply oxygen and fuel to the muscles at a rate adequate to sustain aerobic metabolism for long periods.

However, it is interesting to note that sprinting speed is a good predictor of one’s ultimate performance in distance events.  Nonetheless, a novice endurance runner will get best value from time spent training by working on building aerobic capacity.  A powerful engine is of little use without oxygen and fuel.  But once oxygen and fuel supply are more than adequate, perhaps it is time to focus more on muscle power.

There is an even more general rule about training and that is: repeating the same training stimulus time and time again yields diminishing returns.  When the returns begin to diminish it is worth asking the question: what is now limiting my performance and what training stimulus might best break through the current limit?

Limitations

In recent years several illnesses and also lack of time for training had been the most easily identified limitations, but the past year has been different.  I been free of illness and injury, and have actually spent more time training than during any year of my life – even those years over four decades ago when I could run a marathon in less than two and a half hours, though it should be noted that in those days, other activities especially mountaineering, contributed a great deal to my basic fitness.

In the past year the time spent training has produced substantial gains.  However, about three months ago, in the final few months of preparation for the Robin Hood Half Marathon at the end of September, it was clear that I had run up against a serious limitation.  My aerobic fitness, as indicated by low heart rate when running at an easy pace, was good.   My customary measure of aerobic fitness, the number of heart beats per Km, was typically in the range 630-640 b/Km during low aerobic runs, and there was very little upward drift of heart rate during long runs.    I would have anticipated that such a level of aerobic fitness would allow me to maintain a pace in the range 4:35-4:45 min/Km for the duration of a half marathon, to produce a finishing time of 1:40 or less.   But to my dismay, when I tried to maintain paces in this range, even for a few Km, I simply couldn’t muster the speed.  I could not even maintain 5 min/Km pace for 4 Km.   So it appeared that my limitation at that time was not aerobic fitness.

It was easy to identify the problem: the first factor is that I am in my late sixties, and suffering the general loss of muscle strength that accelerates alarmingly in the later part of the seventh decade.  The second problem was that I had suffered an episode of acute arthritis two years ago that had affected several joints including my left knee.   Painful movement leads to involuntary decrease in application of force, and as a result, my leg muscles, especially quads and hams, had atrophied even more than would be expected due to aging.  The hopping test, in which I measure the total distance covered in 5 consecutive hops on one leg, had deteriorated dramatically from around 9.5 metres to 7.5 metres.  In the subsequent two years lingering pain in the knee thwarted my attempts to introduce a program of plyometrics, while, ironically, marked pain in my arthritic left wrist made it difficult to lift weights.   It was clear that I had to find some way around these problems.

Fortunately, around the time I received an email out of the blue from a runner named Kieren. Several years ago Kieren’s blog had inspired me both to run and to blog, and I had been saddened when he suffered an injury, stopped running, and eventually stopped blogging.  I had discovered incidentally that he still posted occasionally on the Fetcheveryone website, and I had been interested to see that he had taken up resistance training a few months ago.    Although his recent email to me was triggered by my posts on heart rhythm, we got to discussing resistance training. He emphasized the value of squats for building ‘whole body’ strength, but especially for strengthening the major muscles of the posterior chain: the glutes, hams and hip adductors.  He recommended an excellent book by Mark Rippetoe which provided detailed clear guidance on how to squat safely and effectively.

As I mentioned in a previous post, at that stage I commenced a gradual progressive build up of weights and after four weeks was delighted by two outcomes: my painful arthritic wrist was much less painful, presumably due to increased support by stronger forearm muscles, and my pace during stride-outs at around 80% maximum effort, had increased, though of course, this is a rather imprecise measure of improvement.  Nonetheless, the signs were encouraging.  But by that point in my preparation for the Robin Hood half marathon, it was necessary to revert to predominantly aerobic training.  However, I continued with body weight exercises and drills.  Although there was not time to properly assess my ability to sustain a higher speed in those final few weeks before the race, short tempo runs during the taper suggested that I was now able to  maintain a pace of 5 min/Km or even a little faster with reserve power.  In the event, this proved to be the case. I crossed the line in 1:41:50, reflecting an average pace of 4:50/Km for the full 21.1 Km.  Some of this improvement was no doubt due to a successful taper, but on balance, the prospects for further improvement with continuation of strength development looked promising.

Body weight

But before committing myself to a major program of resistance training, it is necessary to consider the crucial issue of possible weight gain.  For the sprinter, the greatest energy cost of running is the cost of re-positioning the swinging leg.  But at the paces typical of endurance running, the greatest cost is the cost of elevating the body on each stride, and this cost is directly proportional to body weight.    Irwin Stillman estimates that a long distance runner should weigh 15% less than the average non-athlete of the same height, though some coaches consider that 10% less than average is ideal.   Until one reaches the state of emaciation where hormonal and immune function begins to be compromised, loss of fat is almost certainly beneficial to the distance runner.   Weight training is potentially effective for promoting fat loss, and therefore, a substantial proportion of the weight change in early stages of a weight lifting program are likely to a beneficial loss of fat.  I am currently about 9% below average weight for my height, so I do not need to lose much more weight.  Some of this deficit is due to muscular atrophy, so I will probably profit from replacing fat by muscle.

But depending on the regimen adopted, gain in muscle mass from weight training might well overshadow the loss of fat, especially for a distance runner with little fat to spare.  So if my running performance is to improve, it is crucial that any gain in muscle mass ‘pays its way’ by producing an increase in power output that more than compensates for the extra work I will have to do in order to get airborne on each stride.   It will also be crucial to ensure that I maintain the ability to deliver enough oxygen and fuel to the muscles to sustain aerobic metabolism for several hours.

Muscle fibre types

This brings us to the key issue of types of muscle fibre.  The sprinter relies largely on type 2B fibres, anaerobic fibres dominated by massive contractile machinery capable of rapid, and hence powerful contraction.  Muscle contraction is produced by  the ratchet-like interaction of actin and myosin fibrils that slide past each other as a result of making and breaking molecular bonds, employing energy provided by the energy molecule, ATP.  Several different types of myosin fibrils exist.  Type 2B fibres contain ‘heavy duty’ myosin capable of very rapid contraction.  Thus, type 2B fibres are best equipped to utilise readily available ATP and creatine phosphate, which can be rapidly converted to ATP.  Although oxygen is subsequently required to replenish the supply of ATP and creatine phosphate, this is usually done at a leisurely rate during recovery.  Therefore, the development of type 2B fibres sacrifices capillary density for the sake of contractile machinery.  These type 2B fibres are of limited use to a distance runner.

The distance runner relies largely on type 1 fibres in which there is a balance between contractile machinery and capillary density, and it addition, abundant mitochondria. The mitochondria contain the oxidative enzymes required to generate ATP by oxidizing fuels such as glucose.  Thus type 1 fibres are well suited to aerobic metabolism.  However, the variant of myosin in type 1 fibres can only contract at about 1/10^th the rate of the variant found in type 2B fibres.  Therefore the type 1 fibres are best suited to producing a modest power output for long periods using aerobic metabolism.   But it is unlikely that lifting heavy weights will do much for the development of type 1 fibres.

The next question is: what fibres are enhanced by resistance training?  The answer is perhaps a little surprising.  Resistance training enhances mainly type 2A fibres.  These are the aerobic fast twitch fibres.  They contain a type of myosin fibril capable a fast contraction, but are also fairly well adapted to aerobic metabolism.  They contain substantial numbers of mitochondria and a moderately high capillary density.    Therefore, they are well equipped for tasks that require a moderately large power output sustained for a moderate duration, tasks such as running up long hills.   As almost all cross country events and many road races include some hills, it is clearly desirable for the distance runner to have fairly well developed type 2A fibres.  Unfortunately, I have poorly developed type 2A fibres.  In my duel with Emily the Keyworth Turkey Trot two years ago, I could not match her on the ascents and had to rely on shrinking the gap during the descents.  Similarly in a 5K parkrun two days ago, I was very evenly matched with a young man on the level stretches, but could not match him on the mild ascents, and again, had to rely on closing the gap during the descents.  So, it is likely that further development of type 2A  fibres will in itself improve my performance on hilly courses.  But the cardinal question is: is it possible to convert type 2A fibres into other types of fibre?  The answer to this question is still a subject of some uncertainly, but encouraging evidence is emerging

Conversion between fibre types

Before tackling the crucial question of the possibility of converting type 2A fibres to the type 1 fibres required by the distance runner, it is intriguing to ask how it is that weight training helps sprinters develop the type 2B fibres that are the key to speed.  Enigmatically, the answer appears to be: by doing very little.  It appears that type 2A  fibres naturally revert to type  2B fibres when not subjected to repeated loading.  It is probable that type 2B fibres are the default state to which other fibres regress if not required to work.  This is illustrated by the fact that after a period of paralysis, the proportion of type 2B fibres is high.   Thus, it is likely that the best strategy for a sprinter is marked periodization.  In the pre-season, he/she should lift heavy weights, leading to the development of type 2A fibres.  Then during the competitive season, the emphasis should be on sharpening neuromuscular coordination.  Meanwhile the type 2A fibres developed during the pre-season weight lifting will revert to the required type 2B fibres.

But can an endurance athlete convert the type 2A fibres to type 1 fibres?  The answer is less clear.  It appears to depend on the initial fibre composition of the muscle.  In a study of 21 cyclists who undertook training program in which volume of training was increased while intensity decreased, there was a significant decrease in proportion of type 2A fibres and a trend toward increased proportion of type 1 fibres, when averaged across the entire group.  However, perhaps the most important finding emerged when the 21 cyclists were subdivided into a group with high initial proportion of type 1 fibres (the HPS group) and those with a low initial proportion of type 1 fibres the LPS) group.  In the HPS group, the change to higher volume, low intensity training produced no appreciate change in fibre composition, whereas in the LPS group, there was a marked increase in type 1 fibres and a decrease in type 2A fibres.   The question of whether or not the difference in initial proportion of type 1 fibres was determined by genes or by previous training was not addressed.

Thus, the study demonstrates that an increase in training volume and reduction in intensity is likely to produce a shift from type 2A to type 1 fibres in some endurance athletes, but not in others, and that difference in training effect is determined by the proportion of type 1 fibres at the beginning of the high volume training.  Unfortunately, the question of whether it is the genetic influences on the initial fibre composition or previous training experience that determines the likely outcome remains unclear.  However, it seems to me that prior training is the mostly likely factor, since cyclists with a genetic predisposition to a preponderance of type 1 fibres would have been more likely to be in the HPS group at the start.

I suspect that due either to my genes or to my childhood experience of running to and from school, I have a natural preponderance of type 1 fibres, and therefore, in my present state, further high volume. low intensity training will not increase my proportion of type 1 fibres.  However, the available evidence indicates that a program of weight lifting might increase my proportion of type 2A fibres and subsequent high volume, low intensity training might lead to an increase in type 1 fibres.

The available evidence also indicates that the outcome of training depends on one’s initial state at the beginning of the training.  There is no single answer to the question of how best to train.  But after a careful evaluation of my own condition, I think that a program of weight training is a good bet in my case.  However it is also noteworthy that in order to achieve the distance runner’s theoretical ideal of a very low amounts a type 2B, moderate proportion of type 2A and a large proportion of type 1 fibres, I need to revert from weight training to aerobic training well in advance of my next half marathon.

There are additional issues to consider.   These include the effect of weight training on hormones, especially growth hormone, and also the question of what particular exercises I should include in my weight training program.  I will return to each of these questions in future posts.  I will finish this post with an account of how I plan to monitor progress.

Monitoring progress

I will monitor three ‘running specific’ variables: my time for a 5K, the distance achieved in 5 consecutive hops on one leg, and my weight.

With regard to 5K performance, I did my base-line test in a parkrun last Saturday.   I achieved a time of 22:19.  I was delighted with this, since in my first parkrun a year ago, run after about three months of systematic training, including both hills and intervals, I had achieved a time of 24:48.  Thus, in the subsequent year, I have managed to reduce that time by about two and a half minutes.   Whether this reduction can be attributed to the intervening aerobic training or to the resistance work and drills over the past few months in uncertain. The fact that I could not maintain 5 min/Km pace for 4 Km three months ago, at the end of a long period of predominantly aerobic training, suggests that it was a combination of both.   Thus, I am cautiously optimistic that an appropriately periodized combination of weights, drills and aerobic training will lead to yet further improvement, though of course, reduction from a starting point of 22:19 is a greater challenge than reduction from a starting point of 24:48.

An finally, as a counterbalance to the somewhat gruesome photos of my efforts to conjure speed from my atrophied leg muscles in the RH half marathon, here are some photos taken during the two-lap parkrun on Saturday, by the husband of Plodding Hippo, a runner and doctor whose wisdom on running-related medical matters is much valued by readers of the Fetcheveryone website.

Nearing the halfway point. Original at http://www.flickr.com/photos/nozzawales/8105220722/in/pool-2059413@N20/

About to begin the final sprint with about 100 m to run. Original at http://www.flickr.com/photos/nozzawales/8105262635/in/photostream

Reflections on the Robin Hood Half Marathon

A week later, I have had time to look back over the Robin Hood Half Marathon, and reflect on the recording from my watch and heart rate monitor.  I had pressed the event marker button at 1, 4,7 and 10 miles so I had estimates of my pace and heart rate in each three mile segment after the initial mile.  As expected from the effort I put into the final few Km, my fastest segment was from 10 miles to  13.1.  However despite a substantial increase in effort, my pace of 4:46 min/Km in that final 3.1 miles was only marginally higher than the average of 4:51 for the entire event.  I expended a lot of effort for a modest gain in speed.   Despite the effort, my heart rate only rose moderately, to an average of 138 over the final 3.1 miles compared with 133 for the entire event.  Thus, the cardiac cost was 659 beats/Km in the final 5 Km compared to an average of 646 for the whole event.  This reflects a small loss of efficiency, but that is not too bad, as efficiency usually decreases when one is tired (and heart rate also rises as body temperature rises).  However the noteworthy point is that despite trying to recruit every available leg muscle fibre, my heart rate was still substantially lower than I would expect for the final stages of a race.  It appears that I just do not have the muscle power to maximise the use of my cardiac output at present.

Half way and its time to increase the pace

My struggle to recruit my leg muscles is also clear in the photos.  At halfway, my hams and calf muscles were quite tight but I was fairly confident that they would get me to the finish, so I decided it was time to increase the effort. By about 12 Km, the effort shows on my face but at that stage, my legs were unwilling to go any faster.   With 3 Km to run, effort was now approaching maximal but the increase in pace was modest.

Approaching 12 Km and my legs were unwilling to respond

Applying more pressure with 3 Km to run

In the final sprint, the tense neck yet floppy wrist suggest that I was not recruiting muscles very efficiently.   However, the facial expression might have been just right for Ewen’s fantasy Hollywood blockbuster in which an elderly professor with cronky legs pits his failing strength against the Vice Chancellor’s pretty PA in a sprint to the finish.  The outcome will determine whether a legacy to the University will be spent on a new limo for the VC or on refurbishing equipment desperately needed for life-saving medical research in the prof’s lab.  But in the more prosaic real world, I was in fact fairly pleased with the way I had run the race, and think I got about as much out of my legs as they were fit to give.

The final sprint

10 metres to go. Enough for one more scalp?

For two days after the event I had moderately severe generalised DOMS but fortunately only a scarcely perceptible localised discomfort in my left calf, so I had not done any significant local damage in my sprint finish.  Towards the end of the week,  I did a session of Peter Magill’s skipping drills and the only noticeable muscle issue was mild tightening of my hamstrings in the final few metres of the skip and kick drill.  This resolved when I slackened the vigour of the kick.

So overall, the HR data and other evidence confirmed what I already knew from my experience on the day.  I need to strengthen my legs, and will start on the free weight program in about two weeks, after I return from a conference in Switzerland, and a few days walking in the Bernese Oberland.  I will assess gains in strength using the hopping test but the more meaningful measure will probably be my time for a 5K, by the end of the year.

At the beginning of the current half-marathon campaign, I was unsure that I could even achieve a time of 25 min for a 5K and was pleased when I did a 5K parkrun in 24:45, with an average HR of 143.  So my time of 23:50 with a somewhat lower heart rate for the final 5Km in the half marathon at least demonstrates that my aerobic fitness and endurance did improve substantially during the campaign, even if the improvement in power was rather modest.   I doubt that I will ever run a 5K in less than 20 minutes again, but I would at least like to get down to around 22 min.    Then I should aim for another half marathon in the spring and perhaps a full marathon in the autumn.

Robin Hood Half Marathon, 2012

The taper for the Robin Hood half marathon had gone fairly well.  In contrast to the final few months of training during which my pace during tempo runs was very disappointing and I had be quite unable to achieve anything approaching a reasonable race pace when I pushed myself in the final few Km of long training runs, I had been pleased that by the end of the taper I could maintain a pace around 4:50 per Km comfortably for short distances.  It was still very uncertain for what distance I could maintain such a pace, so I had very little firm evidence on which to base a pacing strategy in the race itself.  A time anywhere in the range 102 to 108 minutes was plausible.  I decided therefore that I would run by feel rather than by the watch.   As both Robert and Ewen pointed out, this is a bit risky because the extra adrenalin can distort perceptions on race day.  I think I have a fairly good capacity to estimate effort, by conscious attention to the depth and rate of my breathing, and by an awareness of the overall sense of wellbeing or distress generated by the many non-conscious signals that pass from body to brain.  I accepted it would be a bit risky to rely on these sensations, especially as I have only raced once (a 5Km last November) since I ran the Keyworth Turkey Trot two years ago, but I was prepared to take the risk, rather than settle for a sensible target of around 105 minutes.

In the Turkey Trot my arthritis-ravaged legs had let me down.   Although I was pleased on that occasion that I was able to make a good race of it, largely due to an impromptu duel over the final few Km with a young woman named Emily, my time of 108:45 had been unimpressive.    Unfortunately, due to subsequent painful remnants of the episode of arthritis I had not managed to make much progress with the leg strengthening exercises that were clearly required, so once again, today I was starting a half marathon aware that my legs would be my vulnerable feature.

For a few days I had been watching the weather map monitoring the progress of a cyclonic system that had deepened to the east of Iceland mid-week.  As the high pressure that had provided us with some stable weather during the week moved further eastwards, we were in for some strong south-westerly gusts by Sunday,   Perhaps not ideal for long distance running, though I noted optimistically that as the Robin Hood course heads mainly south west in the first half before turning back the northeast, and the winds would probably strengthen throughout the day, we might get some net wind-assistance, .  It was also clear that the temperature would be cool.

Before pinning my race number on my vest last night I popped out to assess the likely temperature and make a final choice between T-shirt and singlet.  The sky was clear, the moon was full and stars sparkled though a crisp atmosphere. If it stayed as clear as this, it would be chilly tomorrow, but I was fairly sure that clouds driven by the approaching cyclonic system would sweep over us before morning, so I elected to pin the number on my singlet.

I set the alarm for a little before dawn, to allow a leisurely breakfast.  As the sun rose the underside of the accumulating clouds turned pink.  The cyclonic system had not quite reached us though the breeze was freshening.  It looked like the weather would be ideal and the rising wind would be more a help rather than a hindrance.

At the start I found a spot near the back of the red pen (for runners aiming for 90-105 minutes), along with a variegated mass of humanity – some wiry, with serious faces and club vests, jiggling around to keep warm; others dressed as Robin Hood, apparently more intent on enjoying the experience than worrying about the stop-watch.  As the wheelchair race was getting under way, the drums increased their tempo, and it was impossible to avoid a surge of excitement. However as we stood waiting I noted that my pulse was a steady 57 despite the rousing beating of the drums.  Rather than being concerned that adrenaline would mask my sensation of effort, I was now a little more concerned that the benefits of my light warm-up might have dissipated.   A few spots of rain fell, but I knew that I would warm up again fairly quickly once we were under-way.

The drums masked the sound of the start horn, but I became aware that the mass of humanity was moving and gathering speed as we approached the inflatable arch that defined the start.  I had little control over pace at this stage, but had reached a gentle trot as I passed under the arch.   In the next few minutes the human mass became more chaotic as individuals struggled to establish their own pace   However, frantic scrambling at this stage is pointless.  I was locked in the midst of a clump of burly men bearing logos proclaiming that they were participants in the Cooper Parry Relay.  When one of them announced after we had covered a few hundred metres that we were now doing 6 min/Km I decided it was time to at least extricate myself from this particular clump, so I tucked in behind a rather muscular young (male) fairy wearing a pretty blue tutu, and followed as he forged ahead.

As we approached the first mile marker, my breathing was relaxed and I recognised the rhythm as one breath every six steps – a rate that I knew I could maintain comfortably for at least the HM distance.  My overall sensation was ‘OK’ though I was aware that my legs were moving  a little less fluently than that they had been during the best of the short runs in the recent taper.  However, at this stage, there were no grounds for serious concern.  As a safety precaution I checked my watch at the mile marker.   The time was 7:46 (equivalent to 4:50 /Km) and heart rate was 130.   I only intended the watch-check as a back-up to avoid serious misjudgement.  Nonetheless I was pleased to see that my pace over the first mile had been at the faster end of my expected range, yet my HR was still well below the upper aerobic zone targeted by HM runners.   Although pleased, I was not surprised as I knew that it was unlikely that either heart or lungs would be the limiting factor today.

At the first drinks station I consumed about 150 ml of water.  I wondered whether the fluid was worth the few seconds I lost in weaving through the still tightly packed mass of runners, but that had been my prior plan so I stuck to it.  As we headed south westward along the wide open boulevard on the north bank of the Trent, I expected the head wind to be challenging.  However, I was still in such a tight mass of runners that I scarcely noticed the wind at all.

As we ran through the campus of the Boots Company, it was necessary to watch out when approaching the sharp bends to avoid collision with runners trying to save a metre or two by running the tangents.  However, by and large, the mass of runners was now fairly streamlined.  I was still breathing with a comfortable 1:6 rhythm, but my legs were definitely not coping well.  My left knee was a little painful and both gastrocnemius and hamstring muscles were tightening.

Shortly after entering the University campus we encountered the only appreciable hill on the entire course (apart for the ramps leading to bridges) and I was happy to let the majority of nearby runners surge ahead as I slowed a little to reduce stress on my legs.  At the top of the rise we passed through the imposing portico into the courtyard of the Trent Building – the administrative headquarters of the University.  Although it was awe-inspiring to run through such an imposing portico, I have some mixed feelings about the grandeur of Trent Building.  When the University administration top-slice my hard-won research grants to cover university overheads, I wonder, in an iconoclastic frame of mind, how much of the top-slice goes to maintain the splendid wood-panelled Senate Chamber and the Vice-Chancellor’s Office. However, today, it was an occasion to simply enjoy the grandeur.

On the descent from Trent Building to the lake I caught up with most of those who had surged past me on the ascent.  As we rounded the head of the lake a wonderful steel band was beating out a rousing rhythm.  Another quick glace at my watch showed that my HR was still 130 (though it had almost certainly been higher on the climb and was now probably a bit below average following the descent).  Although my legs were still uncomfortable, we were now at the half way point and I was fairly confident that the legs would hold out to the finish.  I decided it was time to apply a little more pressure.  As we left the University campus, I scanned the mass of humanity ahead for appropriate quarry to add a little spice to the chase.  At this stage, the majority of the pack were still running with dogged determination and no-one was offering themselves as easy prey.  Most had the demeanour of runners with serious intent.  I could see the green tunics of two Robin-Hoods not far ahead. They were running strongly but nonetheless I decided they would have to do.  However, despite a substantial increase in effort, my legs were reluctant to go much faster and it was not until after the nine mile marker that both Robin Hoods were behind me.

My breathing rate had now increased to one breath every four steps but was still comfortable.  I was sweating lightly but felt more water logged than thirsty, so I did not deviate from my path to pick up any water at the third water station.   As my legs were reluctant to go any faster, I settled in to maintain my place in the pack.  The continual slight shifts of position within the pack made it impossible to focus on a particular person, but I was surprised by just how many of the pack were runners who had forged slowly ahead of me in the earlier stages.  I was confident that I was running a slight negative split, so overall the pack was scarcely weakening.

I had almost forgotten about the wind until we did a dog-leg back to the southwest approaching the 10 mile mark, and the gusty south-westerly asserted itself.  After a few right angle turns in the next mile or so, we were back on the river embankment, passing near to the finishing point, but with a two mile loop along the river bank still to be run.  I could hear an excited voice announcing over the loud speaker that someone of apparent local importance, whose name I didn’t catch, had ascended the slope onto the flood protection embankment leading to the finish as the race-clock passed 1 hour and thirteen minutes.  I estimated that whoever he was, he had about two minutes to run at that point, while I now had about two miles to run.  My brain was still working well enough to estimate that provided my legs didn’t give up during those two miles, my time would be around 102 minutes.

The outward leg of the final loop exposed us once again to the gusty wind and my breathing was deeper now – I was definitely in the upper aerobic zone.  Then there was a short stretch shielded from the wind by trees and enthusiastic spectators; a short sharp pull up to the top of the flood protection embankment, and a final sprint to the finish.   By this stage my leg muscles were tightening quite alarmingly.  In the final 50 metres I tore a few fibres in my left calf.  As I crossed the line, the race clock indicated a little over 102 minutes.  As I had crossed the timing mat at the start a short time after the official start I expect my official chip time will turn out to be under 102 minutes.  According to my watch, my time was 101:50.  [Note added 1 Oct 2012: the published results confirmed 101:50]

I am delighted to have achieved a time at the leading edge of what I thought was possible.  As in the Turkey Trot two years ago, my legs were again the limiting factor, but my time was about seven minutes faster.  There is no doubt that a program of leg strengthening must now be my highest priority.  I also feel a bit sheepish about tearing fibres in my left calf, as I was aware that they were at their limit before I began the final sprint.  However, even though the sprint gained me only a few seconds and three or four places in the finish order, I find it difficult to resist the temptation to treat the final run to the line as a race with whoever else has managed to get to the home straight at the same time.  That surely makes us balanced and worthy opponents.

The end of the taper

It is two days from the end of my taper for the Robin Hood half-marathon on Sunday.  Tomorrow will be a rest day.  On Saturday I will run about 4 Km easily, including several short stride-outs at estimated race effort to dispel any of the sluggishness that can develop during rest days, and consolidate the neuromuscular coordination required for racing.

I am pleased with how my legs have responded to the taper.  In the final few weeks of training I had been disappointed by the fact that I found it difficult to achieve pace anywhere near a reasonable race pace during tempo runs.  I hoped that this was due at least in part to chronic tiredness of my leg muscles, so the main goals of the taper were to allow my legs to recover, while including enough running in the vicinity of race pace to develop the neuromuscular coordination required for racing.

The figure shows the profile of time spent in each of the training zones over the past three weeks.  Despite a 50%  reduction in training volume I have maintained a near constant proportion of around 25% of training time in the upper aerobic zone, throughout the taper    I have been pleased to discover that whereas two weeks ago a pace of 5 min/Km required an effort somewhat greater than I could imagine sustaining for the HM distance, today, I felt comfortable and fluent at pace of 4:50 /Km.   In part this is surely because my legs are less tried, but I think it is likely that incorporating some faster running, together with two sessions of Pete Magill’s drills, has helped re-awaken the muscle fibres required for racing.

So the taper has produced the intended improvement in fluency.  But what does this tell me about my prospect of maintaining that fluency and pace for the full distance? In several of the long runs during the previous 6 weeks I had planned to maintain a pace near HM race pace for the final few Km.  However, the fastest pace I had achieved in a long run was 5:14 /Km – a pace which would produce a time of  110 minutes for the HM.  The evidence from the short runs during the taper suggests that I can do substantially better than 110 minutes, but there is no way in which I can answer the  question of how my legs will cope with the full 21.1 Km distance, in advance of the race itself.

So planning a sensible pace for Sunday is still tricky.  If I start at around 4:50 pace, it is not clear how long I would be able to maintain that pace.  Commonsense dictates that if my goal is to maximise my chance of recording a ‘creditable’ time, I should start at around 5 min/Km pace or even a little slower, and hope that I can run a negative split to get me to the finish in around 104-105 minutes.   However, somewhere deeper in the intuitive recesses of my brain, where less tangible evidence based on my running history is weighed up alongside the numerical data recorded in recent training runs, I believe that I can run a time faster than 104 minutes.  Therefore, provided I feel comfortable after I have emerged from the initial melee of the massed start, I will abandon rationality and prudence, and let the intuitive recesses of my brain set the pace. I will trust that these intuitive reaches of the brain will weigh up the various non-conscious feed-back signals from my body together with subliminal memories from the past in way that allows me to extract the maximum performance that my body is capable of achieving.  In the end, it will be my body rather than the stop-watch that tells me whether or not I have run a well-judged race.

An unconventional start to the taper

As outlined in my recent post, I have been able to train consistently, and largely according to plan, for over a year. I have done virtually all the planned key sessions in preparation for the Robin Hood half marathon on 30^th September – the main problem is that my pace has been well below the target which I set in April.

The target was optimistic.  My 5Km performance a year ago indicated that my target HM pace should be around 115 minutes but I was sure I could do quite a lot better.  108 to 110 minutes might have been a sensible guess.  However, I decided to go with my dream and planned a training schedule aiming for 100 minutes.   The chance of achieving this wild dream depended on how well my aging legs could cope.  My muscles had atrophied not only with age but also as a result of a protracted bout of arthritis early in 2010.  During the Keyworth Turkey Trot HM in December of that year, my legs had let me down.  In the subsequent months I had to abandon my attempted program of plyometrics because of an exacerbation the arthritic pain.  However when I planned my preparation for this years’ Robin Hood HM I included a program of trampolining that I hoped would strengthen my legs sufficiently. As described in the recent post, the trampolining was not enough.  My brief experimentation with lifting free weights in early August has given me reason to expect that a systematic program of lifting weights after the HM is the best medium term plan.  But for now I have a little less than two weeks of tapering to make the best of my current situation.

In fact the two weeks taper period is perhaps the most important two weeks of a HM program.  Done correctly, it can potentially produce improvements of 4 or 5 minutes. This is mainly due to a recovery of the strength and coordination that has been impaired by the rigours of training.  The general principles of what must be done are fairly well established:  decrease training volume rapidly in the first week and more gradually in the second week; maintain intensity while decreasing volume; aim to polish the required neuromuscular coordination by short repetitions at race pace; get enough sleep and eat healthily.

These principles have largely been established in studies of younger runners.  It is reasonable to expect that they also apply to older runners, but the details of how they are to best applied have to be worked out taking account of one’s own strengths and weaknesses.  My major weakness is manifest in my clunky, aching legs.  My potential strength is my aerobic capacity and my fairly economical running style.   So this week the priority is balancing the need for recovery with the creation of the sharpness that comes from running at race pace or a bit faster, while avoiding injury.  Every step that I run this week must have a clear purpose directed towards these goals.  Almost every step I run will be either: warm-up, moderate tempo at around HM pace; striding-out for distances of 50-100 m at around 75-80 % maximum effort with floating between the stride-outs; or cool down.  This week and next I will not run a single step for the sake of achieving either distance or total accumulated volume.

But there is one other thing I will do.  After 36 weeks of fairly consistent running at slow or moderate speeds, there are dormant muscle fibres that need re-awakening and fine-tuning.  So my plan includes a weekly session of Pete Magill’s drills for older runners.  These are mainly playful skipping and similar movements that engage the various muscles required for fluent running.  There are 10 drills but it is not necessary to do all 10.  Six require relatively simple movements starting with  school yard skipping, moving on to high skipping, marching, foot shuffling, butt kicks and high knees.  The seventh in order of difficulty is ‘skip and kick’, which requires moderate hamstring flexibility, but I can do it reasonably well. Three of the exercises are quite demanding: long skipping in which the length of the hops is taxing; bounding which produces a hefty eccentric load on impact with the ground; and carioca, which involves exuberant hip swinging. In the video, carioca is demonstrated by Pete’s youthful, lithe and glamorous partner, Grace Padilla.  In the interest of minimizing risk of injury I decided to omit long skipping, bounding and carioca during this pre-race period.

After a rest day yesterday, today I did the first of the two drill sessions planned for this taper.  One crucial aspect of the drill session is interleaving the drills themselves with stride-outs to encourage incorporation of the recruitment of the muscle fibres awoken by the drill within a fluent running action.  So, after a 16 minute warm up that included 4 stride-outs, I did each of the seven selected drills, following each with a 50m stride-out.  After the completion of the drills and stride-outs, I then did 15 minutes of running at a relaxed but steady pace, not far below my intended HM effort, finishing with an easy cool down and gentle stretching of calf, hams and quad muscles.

It was a very satisfying session.  My legs are still a little clunky, but during the 15 minutes of steady paced running at the end, I could start to imagine myself running fluently again.  I feel that the taper has got off to a good, though perhaps unconventional start.