Archive for May, 2013

Planning the half-marathon campaign

May 27, 2013

Although my campaign to run another ‘good’ marathon before age 70 has been buffeted by various misadventures, including an accident, several episodes of illness and occasional recurrence of arthritis, I have not abandoned my goal.  One the other hand, it is clearly an undertaking that cannot be taken lightly, and the build-up should be gradual.   My target for this year is to run a half-marathon in less than 100 minutes.  Despite building a fairly good base last year, a recurrence of arthritis in the early months of this year had set me back.  So my current task is rebuilding the base.  A few weeks ago, I outlined the principles of base-building. In this post I will outline my strategy for rebuilding the base, but first of all I should set base-building within the overall strategy of preparing for a marathon.

The physiology of a good marathon

Running a good marathon requires many physiological attributes:

  • aerobic capacity (the ability to sustain the required pace with only minimal accumulation of lactic acid) is paramount.  Other key attributes are
  • fuel efficiency, which largely corresponds to the ability to derive a substantial proportion of energy from fat at marathon pace;
  • endurance, which demands minimising the deterioration in pace over time;
  • conditioning of the connective tissues of the body so that they can withstand the rigours of both training and racing,
  • and speed.

Of these speed might seem the least important, but there is abundant evidence that speed over short distances is a good predictor of marathon performance.   In part, this might merely reflect the likelihod that reasonable speed over short distances and the potential for a good marathonanare are independent consequences of an inherited ability to run fluently, but I think there is more to it than that.  Even when endurance has been developed to full capacity, sustained heavy exercise results in a short term loss of muscle strength and power.  Therefore, one must start a marathon with some reserve capacity to allow for this loss.     In fact the Vdot tables initially developed by Daniels and subsequently refined by others, provide a good indication of the required reserve capacity.  A marathon in 3 hours 30 minutes (approximately 5 min/Km pace) would probably be beyond the capacity of a runner who could not run 5K in 21: 50.   My current target of a HM in 100 minutes will require the capacity to run a 5K slightly faster than that.  Last year, when I was at peak of my fitness since middle-age, I ran a 5K in 22:10, so I need to increase my speed.  This was the goal of my program of strength development in the final months of last year, but sadly arthritis intervened before I could convert strength into power, and at this stage, even 22:10 would be out of my reach.  Therefore at some stage between now and my planned half marathon in the autumn, I need to develop more speed.

Periodization

Although one cannot afford to neglect entirely any aspect of the required physiological adaptations at any stage during race preparation, for most individuals, at least some degree of periodization works best.   For someone who lacks the speed required for their target half marathon or marathon pace, a periodized program requires three phases: base-building; speed development; and race specific preparation.   The primary goals of the base-building phase are conditioning the connective tissues, developing aerobic capacity and enhancing fuel efficiency.  In the speed development phase the task is to develop the required speed while allowing the body to recover from the rigours of base-building while allowing only minimal loss of the adaptations made during base- building.  The primary ask of race-specific preparation is developing the ability to maintain race pace for the full distance of the race.  The key sessions are longish runs with a gradually increasing proportion at race pace.   On account of the timing of my episode of arthritis I was left with a total about 28 weeks to prepare for the half-marathon.  I therefore decided on 10 weeks of base-building, 4 weeks of speed development, and 12 weeks of race specific preparation, leaving 2 weeks for a taper.

The components of base-building

Building up to a high volume is the key feature of building the base, so the first question is: ‘what is the target volume?’. In my younger days, when Lydiard’s ideas were spreading by word of mouth, 100 miles per week was the standard.  Because I was more committed to my studies and to mountaineering than to running, I rarely achieved 100 miles a week, but when I did, I was not concerned about my ability to cope with that volume.  However now I am entering my late sixties, I can no longer be so cavalier about volume.  Last year, when I was able to train without illness or injury, I found that whenever I exceeded 40 miles per week I became increasingly tired.  However despite being a year older this year, I hope that the residual foundation from last year will allow a slightly greater volume.

On the other hand, the recurrence of arthritis has left my joints vulnerable.  Therefore, I have devised a compromise strategy.  I will aim to do about 30-40% of my sessions on the elliptical cross trainer.   The leg trajectory is similar to running and by virtue of weight-bearing, the demands on core support are similar.  However the eccentric contraction associated with the jarring impact at footfall is abolished.  For the purpose of calculating total training volume, I estimate 100Kcal of energy expenditure on the Elliptical is equivalent to running 1 mile.  I have set myself the target of building up volume during the first six weeks of base-building to a weekly total of 50 equivalent miles (approximately 30 miles run and 20 equivalent miles on the elliptical) and then maintaining that volume for the subsequent 6 weeks.

But base-building is not just about volume.   The aerobic system should be put under moderate pressure if aerobic capacity is to be developed efficiently, but the pressure should not be so great as to jeopardise my ability to sustain the target volume.   My plan therefore includes three types of session designed to put the aerobic system under moderate pressure.  First are elliptical sessions at a moderate tempo: sufficient to produce a very gradual rise of heart rate and a small rise in perceived effort over a period of 40 minutes.  A small amount of acidity is likely to accumulate, but I this session will be well below the second aerobic threshold (denoted by a marked increase in respiratory rate to above 60 breaths per minute) beyond which lactate accumulates rapidly.

The second type of session is the progressive run, starting at a very easy pace and increasing to just a little short of the second aerobic threshold.  The third type of session is an elliptical interval session modelled on Hadd’s 200/200 fartlek session.  I alternate between 60 seconds at a work rate equivalent to 5K pace and 60 seconds of easy recovery.  Although 5K pace is above lactate threshold, during 60 seconds there is only minor accumulation of lactic acid and this is largely dissipated during the subsequent 60 seconds of recovery.  Over a series of 25 repetitions, the peak HR achieved at the end of each effort epoch rises by only a few beats/min.  All three of these types of session are intended to help develop the enzymes of the Cori cycle that performs the re-conversion of lactate to glucose, and should therefore promote an increased capacity to deal with acidity.

Monitoring for over-training

Maximal increase in fitness is achieved by over-reaching (a level of training stress that produces a mild decrement in performance) while avoiding over-training (the level beyond which persisting damage to performance occurs).  As described in my previous blog posts, monitoring both resting heart rate and heart rate variability provides some guidance, though after several years of experience with these measures, I have decided that these measurements alone are too subject to other influences.  Therefore, I have developed a sub-maximal test in which I measure heart rate at several work rates in low and mid-aerobic zones.  I believe that information about subjective effort might enhance the reliability of interpretation of changes in heart rate.  In my next post I will describe this sub-maximal test, and in the following post, I will tackle the slightly dauting question of whether or not my carefully crafted strategy for base-building has actually produced the intended improvement in aerobic capacity.