Lydiard v. Maffetone

Recent advocates of the Lydiard approach, particularly Hadd and Maffetone, have focused on avoiding the anaerobic zone during the conditioning phase.  This focus has led to a greater emphasis on running at the lower end of the aerobic zone than I believe Lydiard himself advocated, though it is not easy to be certain what Lydiard intended.  He stated that running should at a good aerobic pace, and should leave you comfortably tired after the session.  Enigmatically, he recommended longer runs should be at ¼ effort while shorter runs should be at ¾ effort, but did not define these effort levels.

 

Lydiard ‘mystery coach’

(http://championseverywhere.blogspot.com/2007/09/ask-mystery-coach_24.html – pointed out recently by Rick) states that ¼ effort is the effort that would allow you to go straight out and repeat the run, but this does not quite fit with Lydiard’s recommendation of ¼ effort for 22 miles.  I doubt that even Lydiard recommended immediate repetition of a 22 mile run.  In light of his recommendation that runs during the conditioning phase should leave you comfortably tired, I have interpreted ¼ effort to be the maximum pace that you can maintain comfortably for several hours.

 

Whatever Lydiard meant, Philip Maffetone makes it much clearer that he recommends that most of the training should be in the lower part of the aerobic zone during base-building phase.  His ‘180 formula’ is based on the assumption that the maximum aerobic training pace should be (180-age) with various adjustments for training history.  For me, his formula gives a maximum aerobic training heart rate of 117.  In fact when running, my ventilatory threshold (where breathing depth and frequency increases markedly) occurs at a heart rate around 140-145, so Maffetone’s recommendation is far below my ventilatory threshold.   Even if I adopt Mark Allen’s modified version of Maffetone’s 180 test

  (http://www.markallenonline.com/Default.asp?partner=dua) and add an extra 5 bpm because I am over 60, my maximum aerobic training heart rate would be 122.

 

In my easy 2 hour run last Saturday, I covered 21Km in 2 hours (5:43 /km) at heart rate 120.  This would suggest that my maximum aerobic training pace according to Maffetone/Allen should be in the range 5:40-5:45.  This would also match my interpretation of Lydiard’s ¼ effort pace.  So provisionally, I can conclude that my pace for long runs should be in the range 5:40 -5:45 /Km. 

 

How long is a long run?  Lydiard recommended ¼ effort for runs of 15 miles or more, and he implies that 6 min/mile is a typical aerobic pace for a serious athlete.  Thus when measured in time rather than distance, Lydiard treats runs of 90 minutes or longer as long runs, indicating that for a runner with an aerobic pace of 5:40 /km, 16 Km or more should be regarded as a long run.

 

According to the above interpretation, Lydiard and Maffetone are in reasonable agreement in their guidance for the pace for long runs,  However when we consider shorter runs, there appears to be a crucial difference between Lydiard and Maffetone.  In his guidelines for marathon conditioning, Lydiard recommends two runs at ½ effort and one run at ¾ effort each week, and in addition, he recommends some speed training throughout the conditioning phase.  The speed training might best be achieved by short sprints fueled by ATP and creatinine (known as alactic metabolism).  As I have described previously, I consider it is crucial for an elderly runner to maintain speed, and therefore I have incorporated short sprints into my program even in the early stage of the conditioning phase.  Lydiard recommends ½ and ¾ effort for medium length runs of duration ranging from 60 to 90 minutes.  He states that these runs should be ‘at a good aerobic pace’. If his ¼ effort is at the lower end of the aerobic zone, it would seem likely that he intended ¾ effort to be near the upper end of the aerobic zone (i.e. near ventilatory threshold which for me is near to a heart rate of 140.  In contrast, in an article on the Road Runners Club of America, Maffetone states that you should train at or below the heart rate determined by the 180 test (117 in my case) throughout the base-building period (http://www.rrca.org/resources/articles/slowdown.html ).

 

So which of the two offers the best advice? Maffetone offers four reasons for avoiding the anaerobic zone: 1) aerobic training might decrease the number of anaerobic fibres; 2) lactic acid production might inhibit aerobic metabolism; 3) anaerobic metabolism might suppress fat burning; 4) the stress of anaerobic training might raise cortisol which inhibits aerobic activity.  I believe that there is evidence supporting all four of these assertions but I do not consider any of them is reason to justify spending the entire base building period in the lower aerobic zone identified by the 180 test.  Let us consider each of these reasons a little further:

 

Changes in fibre composition

There is good evidence that fibre composition can change.  For example Ingjer demonstrated that 24 weeks of training that included one predominantly aerobic session and two interval sessions per week, the proportions of type IIA fibres (fast twitch, aerobic) increased while type IIB fibres (fast twitch anaerobic)decreased.  However there was no change in proportion of Type I (slow-twitch fibres) (J. Physiol. vol 294, pp. 419-432, 1979). This evidence suggests that a program including two sessions with some anaerobic work actually increased the proportion of fast twitch fibres capable of functioning aerobically  Thus, in this study, combining aerobic and anaerobic work resulted in a shift towards a distribution of fibres most suited towards running at race paces in the upper aerobic zone.  On the other hand, I have not found any evidence of an appreciable shift towards type IIB (anaerobic) fibres as a result of combining aerobic and anaerobic sessions.

 

Lactic acid production might suppress aerobic metabolism.

It is true that many biochemical process in muscle slow down in as acidity rises.  Warren and colleagues demonstrated many years ago in a study of isolated soleus muscles dissected from mice that as few as 20 eccentric contractions could result in a reduction in force of contraction to around half the initial value (Journal of Physiology, 1993, 468, pp. 487-499).  Furthermore, even after the debilitating eccentric contractions, the force triggered by applying caffeine (which promotes contraction without the need for an electrical, signal from the nerve) was normal, implying that the contractile machinery (actin and myosin) was still able to function, but the failure was due to impaired coupling of the electrical signal from the nerves to the contractile machinery.  They did not identify what caused the loss of contraction strength, though some metabolic effect, such as altered acidity or possibly changes in some other ions such as potassium ions, essential for efficient electrical conduction, would be likely culprits. 

 

This rapid loss of strength following powerful eccentric contractions observed by Warren might be responsible for the fact that it is impossible to sprint for more than a few hundred metres, and may even contribute to the inability to sustain a pace in the lower part of the anaerobic zone for more than 10K.  However, the body corrects imbalances in acidity or ion concentration are on a time scale of minutes or at most a few hours.  In the short term increased respiration, which removes carbon dioxide and thereby lowers levels of carbonic acid in the blood, corrects blood acidity within minutes.  Excretion of ions by the kidney will correct any remaining imbalances over a time period of an hour or so.

 

Thus, adverse effects of acid might effect the ability to deploy aerobic metabolism within a run, and hence suggests that the anaerobic state should be avoided during long runs.  However, acidity developed during one training session will not be sustained to the next day’s session and hence, the acidity itself cannot be a reason for avoiding the anaerobic zone in some sessions, provided the program includes an adequate number of long aerobic runs.

 

Fat burning

It is probable that the enzymes that metabolise fat function less well as acidity level rises.  Therefore, if one wants to promote the development of these enzymes, it is almost certainly best to do long runs in the lower aerobic zone, but in itself this is no reason to avoid the upper regions of the aerobic zone for all sessions in the conditioning phase.  In fact it might be argued that there is limited value in developing the enzymes that burn fat only in the lower part of the aerobic zone if race pace will be in the upper aerobic zone. It might be helpful to do some sessions in the upper part of the aerobic zone with the explicit goal of increasing the ability to clear hydrogen ions when working in this zone and hence to facilitate fat burning even in the upper aerobic zone. 

 

Cortisol production

Cortisol is a catabolic hormone produced when the body is stressed. It actually promotes the breakdown of protein and inhibits muscle hypertrophy.  Thus, it is indeed crucial to avoid excessive cortisol production during the base-building phase.  There is little doubt that doing too many hard anaerobic sessions creates a risk of excess cortisol production, as does pushing up total training distance too rapidly.  However, this is not a reason for avoiding upper aerobic sessions provided these do not leave you feeling continually tired and run-down.

 

Conclusion

So, it does not appear to me that any of the reasons Maffetone proposes are adequate reasons for avoiding the inclusion of some upper aerobic, or even anaerobic, sessions during base-building provided there are an adequate number of low intensity long runs and the total work load is not too stressful.  Thus I consider that Lydiard’s suggestion of one ¾ effort session and two 1/2 effort sessions in the week is fine provided you avoid becoming run-down.  This of course requires judgment, and it is probably best to err on the side of caution when in doubt.

 

An even more important issue

I think that both Maffetone and Lydiard omit the most important issue of all.  That is the mechanism of muscle damage and adaptation. Recent evidence about the role of satellite cells, which are a form of stem cell that participate in muscle repair, has provide the beginning of an understanding of these mechanisms, but that is a discussion that will have to wait for a future blog.

 

Progress

This week, I have taken two steps to implement the Lydiard conditioning phase.  On Tuesday and again on Thursday, I took the initial step towards including some upper aerobic sessions in my schedule,  On these days, during runs of 6 and 7 Km respectively, I progressively increased pace so that I covered about 4-5 Km in the mid to upper aerobic zone.  Apart from two or three interval sessions during the winter, I have not run in the upper aerobic zone for over six months.  It felt good to be running at a moderate pace, though I found that my muscles felt a little stiff the day afterwards.

 

Yesterday, as a check on my estimate of the appropriate pace for a long run, I did 16Km at 5:43 /Km.  My mean heart rate was 119, which was very slightly lower than that recorded during a 21 Km run at the same pace the previous Saturday.  Thus, if I wished to follow Maffetone’s recommendation (target heart rate 117), 5:45 /km would be the appropriate pace for long runs, though if I want to follow Mark Allen’s modification, and increase the target heart rate to 122, I should aim for about 5:40 /Km.  I am inclined towards Mark Allen’s recommendation.  This pace is approximately 1 min per Km slower than my target half-marathon time.  This is a fairly modest objective and should allow me to enjoy some relaxed running through the bluebells in the next few weeks.