Archive for December, 2014

Reminiscences of 2014: Modifying the marathon training of Ed Whitlock

December 30, 2014

Memories of times past

When I had run marathons in the 1960’s it was an event for wiry young men. Typically a few dozen of us lined up across the roadway at the start. We expected to finish in a time somewhere between 2:15 and 2:45 although we were not fixated on time. In that era the IAAF did not recognise world records for the marathon because courses were not considered comparable. Boston was point-to-point and down hill. Similarly the Polytech Marathon in the UK was a point to point from Windsor to Chiswick.   But despite the fact that the marathon community was a small fraternity of wiry young men who trained fairly hard with little expectation of public recognition, the romance of the marathon was beginning to grow.

At the beginning of the decade, Abebe Bikila had won gold running barefoot in Rome. Four years later in Tokyo, he again won gold in a time more than three minutes faster than his time in Rome. At that time we did not appreciate the significance of Bikila’s Ethiopian origins, but we were inspired by his charisma.

The other charismatic figure of the 1960’s was Arthur Lydiard.   The success of Peter Snell, Murray Halberg and Barry Magee in the Rome Olympics imbued Lydiard’s training method with a magical aura.   Although few of us had read his first book, Run to the Top, that appeared in the early sixties, the key principle of building a base by running 100 miles a week at a good aerobic pace had thoroughly permeated the distance running world via word of mouth. Lydiard had not defined ‘a good aerobic pace’ in precise detail, and most of us probably ran it a little too fast. I usually ran at about 6 minutes/mile which was only about 30 sec /mile slower than my marathon pace. Nonetheless, this pace felt easy. After Percy Cerutty’s daunting Spartan approach with its killer sand-hill runs, Lydiard’s advice ‘to train. not strain’ seemed almost too soft, but the evidence from Rome was proof that it worked.

By 1968, the foundation of the modern marathon had been well laid and the event was about to emerge from the status of a challenging but obscure historic relic reserved for hardy young men. In the preceding December Derek Clayton had run under 2:10 in Fukuoka. Two years later, when I lined up for the start of the Australian marathon championship in Melbourne, I was a little disappointed that Clayton, winner of that event in both 1968 and 1971, was not there.   Not that I would have had any expectation of keeping him in sight for long, but if he had been there it would have nourished the almost-credible but fading illusion of belonging to a small but select fraternity. That same year Frank Lebow and Vince Chiapetta organised the first New York Marathon. Initially it was a small event confined to laps of Central Park, but when the event moved onto the streets of the five boroughs with over 2000 entrants in 1976, the era of the big city marathon had begun.   However, by that stage, I was no longer running marathons. My running had been displaced, initially by mountaineering, and then, after I married, by hill walking.

When I took up running again in my late fifties, the elite event was not all that different. It was a little faster and the Kenyans and Ethiopians were beginning to assert their dominance. The truly amazing transformation had been blossoming of the marathon as a massive community phenomenon. Thousands of runners, tens of thousands in the larger city marathons, started with expectations of finishing times ranging from 2:15 to 6 hours or more.

Out of curiosity I decided to run the Robin Hood Marathon a decade ago.  It was over thirty years since my last marathon, the ill-starred 1972 Polytechnic marathon in which we ran an extra three miles or so, after the lead car broke down and we went off course. More than three decades later, after a brief preparation, I found myself at the start of another marathon, engulfed in a vast ocean of variegated humanity   I spent far too much energy struggling to find some space in the melee, but eventually settled in comfortably     I reached half-way in 93 minutes but not surprisingly, I slowed badly after 20 miles, finishing in 3:27. At that time I considered that it would be a fairly straightforward matter to achieve 3:15 or even perhaps sub-3 hours if I trained systematically.

Little did I realise that I was on the edge of a seemingly inexorable descent into old age.   During my sixties, the various minor health problems that had dogged me for years started to loom larger in my life.   By early this year it was clear that if I wanted again to race a marathon I should not wait too long before embarking on systematic preparation.

Training in spring, 2014

Training this year has been an intriguing adventure. In the spring I began gradually increasing the length of the weekly long run and by early May, I was running up to 34 Km on Sunday morning – very slowly.   I was a little disconcerted by the lingering tiredness and aching connective tissues.  After the long runs I immersed myself waist deep in cold water in a wheelie bin, which provided some relief.  However in June I was knocked sideways by a bout of flu, and then in July, tore my gluteus maximus when leaping full length to catch a ball during a game of rounders – a team building exercise after a long day of project planning with my research team. It was a freak injury with an identifiable immediate cause, but I think that being over-tired makes a significant contribution to most muscle injuries.   Consistent with this interpretation, it took me a while to get going again.

Medical students are encouraged to heed Occam’s Razor: ‘Plurality of causes must never be posited without necessity’. However, in my experience, focusing on a single cause for an event often leads to failure to identify effective future prevention strategies. Summer flu followed by a torn muscle suggested it was time to reconsider my strategy.

Modifying Ed Whitlock’s approach

Rather than exhausting myself in a weekly long run, I decided to try Ed Whitlock’s approach of multiple easy longish runs each week, initially aiming to build gradually to 4 two hour runs per week by mid-December. Ed modestly states that his method works for him, but he is reluctant to recommend it to others. However, even accepting that Ed is endowed with an exceptional natural talent for marathoning and a predisposition to age well, his phenomenal performances suggest that his training can’t be holding him back.   Is there an understandable explanation for the success of his training strategy?

One possibility is that a training load that is spread fairy uniformly across the week is less likely to produce marked transient exhaustion than a traditional marathon program dominated by the weekly long run – even if length of the long run has been increased gradually. Each training session contributes to both fatigue and eventual fitness. In the short term the rise in fatigue is more prominent, but fatigue fades fairly rapidly. The gain in fitness is less immediately apparent, but takes longer to fade away.   At any point during a training program, the ability to resist injury and also the ability to race well, is determined by the difference between accumulated fitness and accumulated fatigue.

Because fatigue fades more rapidly, after an arduous training program, performance is usually enhanced by a taper during which fatigue disappears more rapidly than fitness. Conversely, during arduous training, risk of injury or illness is likely to be minimised by avoiding abrupt increases in fatigue that eat into the margin of reserve between fitness and fatigue.

Following a suggestion from Laurent Therond, I use a fairy simple mathematical model based on plausible values for the rate of decay of fatigue and of fitness to estimate my reserve of fitness during training. (I will post the details of the calculation on my calculation page soon).   The units are arbitrary and the precise numbers should not be taken too seriously, but the principles emerge fairly clearly. In May, following several months of cautious increase in training volume, my fitness reserve typically rose to around 500 units by Saturday, but fell dramatically after Sunday’s long run. For example, after a 34 Km long run in May, my estimated fitness reserve fell from 591 on Saturday to 368 after the long run on Sunday.

More recently, after several months of Whitlock-style training, my fitness reserve remained stable in the range 500 to 600 units throughout the week. Furthermore, my total training load was over 20% greater than it had been in May. However, by the beginning of December, I was just a little disconcerted. My training load was substantially greater than at any time in the past 40 years and I was aware of a mild accumulation of fatigue in some of the long runs. On two occasions I had felt a few fibres in my hamstrings give way when I bounded up a flight of steps to surmount the River Trent flood defences. On each occasion shortening stride alleviated the discomfort, but it indicated that I was not far from my safe limit.

In any case I intended to introduce some progressive runs into my schedule early in the New Year as a part of specific training for spring marathon. I therefore decided in the third week of December that I would cut back to 2 easy two-hour runs per week, and introduce some progressive runs to see how comfortably I could maintain a pace near marathon pace. After a short recovery session on Monday, my reserve fitness score was at an all-time high of 680.   On Tuesday morning, heart rate and heart-rate variability confirmed that I was in a relaxed state, so I set off for a 10K progressive run. After an easy start, I gradually increased the pace and by the end was feeling very fluent. It was a wonderful sensation to be running freely.   Retrospective analysis revealed that my pace in the final stage was 5 min/Km and heart rate at 83% HRR.   In my youth 5 min/Km would have scarcely been a jog, but on Tuesday it was exhilarating. Of course, it is virtually impossible that I could maintain HRR at 83% for a full marathon, so there is no reason to adjust my target marathon time downwards, but the wonderful thing was that I felt more like a runner once again.

On Wednesday I did a short high intensity interval session that I do frequently without overt evidence of exhaustion. I was little disconcerted to find in retrospect that my heart rate was higher than usual. The reason became clear that night. I was kept awake by a rising fever and a horrible cough that sent lancing jabs of pain through my head. The fever lasted for five days, and even since it has settled I have had a rather irritating cough.

A pause for recovery

Our family spent Christmas at my wife’s brother house in the Lake District. My wife’s brother is a former mountain guide and is currently Safety Advisor for a company that provides leadership training in various formats including outdoor adventure. Christmas at his house usually includes an adventure or two. This year it was mountain biking on Christmas Day and caving in the Yorkshire Dales on Boxing Day. It seemed to me that getting a bit of fresh air in my lungs would be more likely to help my recovery than harm it. Though I was the oldest member of the party, I was able to hold my own with the youngsters fairly well on both days. However, when I had to hoist myself onto a rock ledge while my feet dangled freely in the air below, to exit one of the caves, what would normally have been a simple manoeuvre had me struggling to find the required strength and brought home to me that I have not yet fully recovered.

Cycling on Christmas Day

Cycling on Christmas Day

Pause for the group photo. I am fourth from rigth (with dark glasses)

Pause for the group photo. I am fourth from rigth (with dark glasses)

Caving on Boxing Day

Caving on Boxing Day

Exit from Thistle Main

Wriggling out of Runscar Cave

P1040134

Conclusion

So what is the conclusion? In the final few months of the year, I had achieved a larger volume of training than in any other 12 week period over the past 40 years. At the end of the 12 weeks I was running more fluently than at any time in recent years, though there were a few hints that I was on the edge of over-training. As I began to cut back the volume in mid-December, I was laid low yet again by a viral infection. Occam’s admonition against seeking unnecessary ‘plurality of causes’ would encourage me to look no further than the fact that many of my work colleagues and students had been suffering from upper respiratory infections at the time. The immediate cause of my illness was no doubt exposure to a sea of nasty viral particles. But I suspect that least in my case, training added a little to the vulnerability.

Nonetheless, I consider that on balance, in 2014 I have laid of solid base. Whitlock-style training is a viable proposition. It facilitates the building of a large training volume while avoiding sporadic peaks of stress. But like any training program that pushes the limits of ones reserves, for a cronky old-timer the best laid plans cannot eliminate the element of unpredictability.

The immediate challenge is to throw off the vestiges of my recent upper respiratory tract infection, without losing too much fitness. My experience in recent years is that for an elderly person, fitness dissolves very rapidly during complete rest, so I will aim for an active recovery in which I build up training volume gradually over a few weeks. Once I am back into full training, I will persist with the Whitlock principle of multiple longish runs at an easy pace each week. However if I am to be ready to race a marathon in the spring, I need to sharpen-up a little. Ed relied largely on short races for sharpening, but the demands of my present work schedule make it necessary for me to fit in two of the easy-paced long runs on the week-end, making racing impractical.   On the other hand, progressive runs that reach marathon pace in the later stages provide race-specific experience without sustained stress, and seem to me the form of sharpening that best suits my present circumstances. So my key sessions will include a progressive run along with several longish runs at an easy pace, each week.

Happy New-Year

Advertisements

Running Efficiency

December 2, 2014

Most endurance athletes focus their training on attempting to increase their aerobic capacity (VO2max) and their endurance. Training increases aerobic capacity by increasing the ability to deliver oxygen to muscle fibres and by increasing the capacity of mitochondrial enzymes to generate energy by oxidation of fuel. However our maximum capacity to generate energy by oxidation of fuel appears to be limited by our genes and/or early development.

The traditional approach to improving endurance is the long run. This increases resilience of muscles, tendons and ligaments, and enhances the ability to metabolise fats.   Once we have trained our aerobic capacity to our limit, and we have developed sufficient endurance to sustain us for the duration of our target event, what scope is there for further improvement in performance? The remaining option is increasing efficiency: that is the effectiveness with which we can use energy to produce speed.

Efficiency

Figure 1 shows speed (in metres/min plotted) against rate of energy production (VO2 measured in ml/min/Kg) for three hypothetical athletes. The slope of each line represents the efficiency of each athlete.   The line with medium slope represents the average runner in the sample used by Jack Daniels to derive the VDOT charts in his book ‘Daniels Running Formula’. The steeper line represents an athlete 10% more efficient than average. The less steep line represents an athlete 10% less efficient than average. Greater efficiency indicates a greater speed for a given rate of energy production. Note that the lines are almost straight, indicating that efficiency is nearly constant across a wide range of paces, though there is a minor degree of flattening of each line at higher paces, indicating a somewhat lesser increase in pace for each additional unit of oxygen consumed.

Figure 1: The relationship between pace and aerobic energy production.  These lines are derived from the data used by Jack Daniels to derive his VDOT tables. The middle line (brown) is the data for an athlete who had the average efficiency from the sample studied by Daniels. The upper (blue) line represents an athlete who is 10% more efficient than average.  The lower represents an athlete who is 10% less efficient than average.

Figure 1: The relationship between pace and aerobic energy production. These lines are derived from the data used by Jack Daniels to derive his VDOT tables. The middle line (brown) is the data for an athlete who had the average efficiency from the sample studied by Daniels. The upper (blue) line represents an athlete who is 10% more efficient than average. The lower represents an athlete who is 10% less efficient than average.

If each of the three hypothetical athletes had a VO2mx of 72 ml/min/Kg (typical of an elite distance runner) the athlete with average efficiency would achieve a pace of 350 metres/min at VO2 max while the athlete who was 10% more efficient would achieve a pace of 385 m//min. At 80% of VO2 max (57.5 ml/min/Kg), the athlete with average efficiency would be expected to achieve a pace of 293 m/min while the athlete who was 10% more efficient would achieve 322 m/min. It should be noted that for an athlete with a lower VO2max, the pace at VO2 max and at any given percentage of VO2max will be less, but the relative gain in pace from an increase in efficiency will be similar. In other words, for two athletes with the same VO2max, a 10% improvement in efficiency would result in 10% faster times in races run at any given proportion of VO2max.

Might training produce an increase in efficiency of 10% or more?   The measurements of Paula Radcliffe performed by Andrew Jones for more than a decade provide clear evidence that the answer is yes. In fact, the data shows that Paula achieved a 15% increase in efficiency over the decade from 1993 to 2003*. Her VO2max remained virtually constant at around 70 ml/min/Kg over this period. Thus, a major factor in Paula’s phenomenal marathon record of 2:15:25 recorded in 2003 appears to be the remarkable improvement in efficiency. How might an athlete improve efficiency?  There are two possibilities: increasing biomechanical efficiency and increasing metabolic efficiency.

Biomechanical efficiency

There are three major energy costs of running:

  • overcoming the braking that occurs while on stance;
  • getting airborne;
  • swinging the leg forwards after lift-off from stance.

There is also the cost of unnecessary tension or movements of other body parts, but as is well illustrated by Emil Zatopek and Paula Radcliffe, who both achieved phenomenal performance despite unnecessary upper body movements, the cost of such movements is relatively small, and there is unlikely to be more than a slight gain from reducing them.

Minimizing the sum of the three major costs requires a balance between conflicting effects. At a given cadence (steps/min) braking cost increases as the cost of getting airborne decreases because less time in the air inevitably results in a larger proportion of time on the ground. Although braking only occurs when the point of support is in front of the centre of gravity, braking cost cannot be reduced merely by attempting to land with the foot under the body, because at constant speed the forward-directed impulse generated after mid-stance and the backward directed impulse generated by braking before mid-stance must be equal (after allowing for overcoming wind resistance).  For a give cadence, the cost of braking can only be reduced by spending more time airborne.

During a marathon, many runners spend an increasing proportion of the time on stance as the race progresses. This is likely to result in greater braking and reduced efficiency. It is noteworthy that the well-known picture of Paula Radcliffe at mile 14 on her way to victory in the 2007 New York marathon shows her getting well-airborne. This demonstrates that she had adequately developed reserves of the leg muscle power required to get airborne. Andrew Jones’ measurements demonstrated that her vertical jump performance increased from 29cm in 1996 to 38cm in 2003.

Paula Radcliffe airborne at mile 14 in the New York marathon, 2007.  Photo by Ed Costello, Brooklyn, NY,US

Paula Radcliffe airborne at mile 14 in the New York marathon, 2007. Photo by Ed Costello, Brooklyn, NY,US

The cost of getting airborne can be reduced by increasing cadence, because the body falls a lesser distance during a series so short hops than during a longer hops covering the same distance, simply because a freely falling body accelerates, thereby gaining greater speed the longer it is airborne. The optimum cadence increases with increasing speed, because if cadence does not increase with increasing speed, stride length would necessarily have to increase disproportionately, resulting in heavy costs of getting airborne and also braking. However, there is a limit to the gains that can be achieved by increasing cadence, because the cost of moving the swing leg forwards increases in proportion to cadence (as shown on the my calculations page).

Nonetheless, many recreational athletes have scope for increasing efficiency by increasing cadence. The study by Heiderscheit and colleagues indicates that a typical recreational runner might improve efficiency by decreasing both airborne costs and braking costs by increasing the self-selected cadence by up to 10% . This increase in cadence also reduces stress at the joints by virtue of the reduction in forces required to get airborne and overcome braking.   Heiderscheit reported that a 10% increase in step rate from a self-selected mean step rate of 172.6 ± 8.8 steps/min at a pace of 2.9 ± 0.5 m/s led to an almost 20% reduction in energy absorbed at hip, knee and ankle joints.

It is probable that Paul Radcliffe achieved optimum balance between the cost of getting airborne, braking and advancing the swing leg largely by virtue of fairly intense running, together with hopping drills and weight lifting.   While training near to race pace might optimise neuromuscular coordination, I suspect that the major requirement for optimising mechanical efficiency is adequate muscle power. Although I do not have direct evidence to prove it, I think it is plausible that a small amount of high intensity training will achieve as much gain in mechanical efficiency with less total wear and tear on the body compared with a larger volume of threshold training, simply because training near to maximal effort is more effective for improving muscle strength and power.

Metabolic efficiency

Metabolic efficiency of oxygen consumption is a measure of the amount of mechanical work (and hence speed) that can be achieved from the consumption of a given amount of oxygen. Several factors influence this. The most important is the fact that the efficiency of conversion of metabolic energy to mechanical energy during contraction of a muscle fibre is greatest when the speed of contraction is near the middle of the range of contraction speed that can be achieved by that fibre. When a fibre contracts too slowly it consumes energy developing tension that does little work. Fast twitch fibres have an optimum speed of contraction that several times faster than that of slow twitch fibres. But the speed of fibre shortening during distance running (and also cycling) is better matched to the optimum contraction speed of slow twitch fibres.

It is noteworthy that many of the large muscles that act at hip and knee cross both joints, flexing one while extending the other or vice versa. However during running hip and knee flex simultaneously or extend simultaneously. Consequently, the rate of change in length in these muscle during running is small. Thus type 1 fibres which are well suited to the isometric contractions required to maintain upright posture are also well suited to distance running during which contraction rate is slow.

In the case of cycling, there is direct evidence that efficiency of metabolic to mechanical conversion is greater in individuals who have a higher proportion of type 1 fibres. Although I do not know of any similar measurements in runners, it is very likely that runners with more highly developed type 1 fibres will be more efficient.

The most effective way to develop type 1 fibres is likely to be consistent high-volume training over a sustained period. It is likely that a major part of Paula Radcliffe’s improvement in efficiency was consistent training, with a gradual increase in training volume over a period of a decade. As discussed in my previous post, Paula did a lot of her training at a moderate or high intensity. It remains a matter of speculation as to whether she could have achieved similar phenomenal marathon performances with less damage to her body by a more polarised approach, in which a modest amount of high intensity running was accompanied by a larger proportion of low intensity running. Perhaps she could have achieved similar improvement in metabolic efficiency with a larger proportion of low intensity training over a longer period of time. My own view, based on Skoluda’s evidence that many distance runners have evidence of sustained high levels of the potentially harmful catabolic hormone, cortisol, is that for many athletes a polarised approach offers the best prospect of gradual improvement in metabolic efficiency and hence, the prospect of year-on-year improvement over many years.

Conclusions

Paula Radcliffe’s spectacular 15% increase in efficiency over a period of about a decade, despite an approximately constant VO2max, provides compelling evidence that a worthwhile enhancement of efficiency is possible. It is likely that a combination of high intensity training, hopping drills and weight lifting honed her biomechanical efficiency.  For many recreational athletes, biomechanical efficiency might also be improved by increasing their self-selected cadence by as much as 10%.  It should be noted that optimum cadence increases with speed.

It is also likely that a gradual improvement in metabolic efficiency over a period of more than a decade was also a major contributor to Paula’s improved efficiency.  It is likely that she achieved this by consistent training, with a gradual increase in volume over the years.  Whether or not she might have achieved a similar enhancement of efficiency with a less damaging, more polarised approach to training remains a matter for speculation. Nonetheless, in my opinion, for many athletes, a polarised approach is likely to offer the best prospect of gradual improvement in metabolic efficiency over a period of many years.

-oOo-

*A minor point to note is that Andrew Jones estimated speed at VO2max by assuming a linear increase in pace with increased VO2. This is likely to produce a small over-estimate of actual pace at VO2max, because in reality the curve flattens a little at high values of VO2. Nonetheless, provided all the measurements are made at a similar region of the curve, the error in estimate will be consistent across different measurements. It is pace at around 80% of VO2max that matters most to a distance runner.