Does training induce long term muscle damage?

A glance down the list of single-age world records for the marathon reveals that a few names occur on more than one occasion. In those instances the same name always occurs within a span of a few years, apart from the instance of Ed Whitlock whose name appears 11 times, but even these 11 appearances are clustered within the past 15 years. This pattern demonstrates that it is difficult to remain at the top for more than a few years, and suggests that the stress of training and racing required to get to the top might produce damage that limits the tenure at the top .

This proposal becomes even more plausible in light of the evidence that heavy training can produce a long lasting over-training syndrome, and also the controversial evidence regarding the reversed-J shaped relationship between training load and health outcomes, such that moderate training load enhances health but very heavy training might damage health.


The fatigued athlete myopathic syndrome

One variant of the over-training syndrome is the fatigued athlete myopathic syndrome, in which it appears that muscles have a limited capacity to recover from exercise. Although the pathophysiology of this condition remains enigmatic, one thought-provoking feature is the abnormal shortening of DNA telomeres in muscle reported by Collins and colleagues from Capetown. Telomeres are DNA caps at the end of chromosomes. They become shorter following the cell division that occurs across the life-span in order to replace worn-out tissue,  This implies that there is a limit to the number of cell divisions that can occur during a lifetime. The shortening of telomeres is regarded as a marker of the aging process. In muscle, repairing the short term damage induced by training, especially the disruption of muscle fibres produced by the eccentric contraction at foot-strike, is dependent of the division of satellite cells, a type of stem cell unique to muscle. The observation by Collins of shorter satellite cell telomeres in biopsies from the vastus lateralis muscle in athletes suffering from the fatigued athlete myopathic syndrome, compared with healthy asymptomatic age- and mileage-matched control endurance athletes, suggests that the origin of the myopathic symptoms might indeed be attributable to damage produced by training and/or racing.

However, a key issue is the observation that age and mile-matched control athletes without symptoms of fatigue had suffered less shortening of their telomeres. Thus, it does appear that some athletes do suffer damage that limits their running career, but this is not a universal consequence. Kadi and Posnet report that when satellite cells are heavily recruited to regenerate skeletal muscle in athletes, telomere length is either dramatically shortened or maintained, possibly even longer than in non-trained individuals.   What are the factors determining whether or not training results in abnormally shortened telomeres? The answer is unknown.


What about the telomeres of elite masters marathoners?

It is unlikely that the seven elite masters marathoners discussed in my two previous blog posts suffered excessive shortening of their telomeres, and even plausible that they maintained longer telomeres that the average non-trained individual. This is mere speculation, but the existence of a mechanism by which some, but not all, athletes suffer sustained muscle damage adds plausibility to the proposal that these seven athletes suffered less sustained training-induced muscle damage than the average athlete, contributing not only to their phenomenal marathon performances but also to their impressive 1500m times.

If so, was their resistance to sustained damage due to their natural predisposition to longevity or might it be attributed to their training schedules? As the seven followed a variety of different training schedules, it is unlikely that the type of training schedule was a major influence. Nonetheless, in my previous post, I discussed the evidence that the two who followed the most markedly polarised programs with a large amount of easy paced running and a small proportion of fast running (Ӧstbye and Whitlock), exhibited greater longevity at the top of the world rankings than the two who appear to have included a greater amount of training at tempo pace or faster (Turnbull and Hosaka).   But it should be noted that Hosaka is still only 65 and might yet upset this observation.



Overall, it is plausible that long term muscle damage induced by training does limit the running careers of some but not all athletes. It is likely that a natural predisposition to longevity helps protect against the damage. However, the training of elite masters marathoners provides a thought-provoking hint that a polarised program that minimises the stress associated with a large training volume might be the most effective way to train in order to achieve longevity of one’s maximal level of performance.

14 Responses to “Does training induce long term muscle damage?”

  1. Ewen Says:

    Are you considering undertaking the markedly polarised training program Canute? If so, I’m interested to see what shape it may take.

    • canute1 Says:

      Yes, at present I am working on a markedly polarised program based on Whitlock. Like Whitlock, I am building up the volume very slowly. I will describe my current training in my next post, though I suspect it will be several months before I can draw any definite conclusions from my own experience.

  2. Rob Youl Says:

    Look forward to reading about the updated training protocol once you’ve tried it Canute. Lot of interest in the polarised approach lately, (even though it has been used extensively).

    • canute1 Says:


      Thanks for your comment. I will post an account of my initial experiences with a schedule based on Ed Whitlock’s approach, whitn the next few days.

  3. Robert Osfeidl Says:

    I wonder how much the mental side required to perform at the wold class level has an effect on both performance and health. To peform at such a high level one has to be very focused and dedicated to training and racing, as well as having the raw physical talent.

    Could long term mental stress associated with trying to peform at your peak erode ones ability to keep the catabloic and anabolic balance required. It only takes a few months of getting the balance wrong to drastically reduce your fitness. Too many knocks like this could easily take you out of the running for someone who could maintain world class performances year after year.

    My guess the harder you try to get to the top the greater the chance you’ll overstep the mark. Most runners never reach world class level despite trying the best they can. We just glimpse the few that do make it. As you point out Canute, those who are able to maintain world class performance over decades is vanishingly small.

    I suspect not aiming so high and not pushing so hard could allow one to lower the risk of mental and physical burnout, and with it increase the chance of peforming at a high level for much longer. To pick out some figures out the air to illustrate – perhaps one could performan at about 99% of your absolute physical capacity for two years, but perform at 95% for a decade, and 90% for three decades.

    Perhaps if one is super patient and want to break age graded records in your seventies then planning in your fourties onewards to train consistently year and year at a healthy and long term maintainable level with small risk of over reach could give you the best platform when you finally step up to the plate for breaking records. Such an approach would be about maintain fitness decade after decade and waiting for everyone else to slow down, rather than trying to maximize your fitness right now.

    • canute1 Says:


      Thanks for your comment. I agree that it is plausible that many athletes who have pushed themselves to their utmost limit have actually gone beyond their limit and thereby hastened their decline. I also agree that one way to reduce the risk of an early decline is to push only to 80 or 90% of one’s limit.

      However, I suspect that it might be possible to get very near to the ultimate limit without damage, if sufficient care is taken. I base this speculation on two items of evidence: the broad body of evidence favouring polarised training; and the anecdotal evidence provided by Ed Whitlock.

      • Robert Osfeidl Says:

        The success of Ed Whitlock is ceratinly inspriatonal and encouraging.

        I suspect getting all aspects of your life balanced over the decades will be important. So eating well, sleeping consistently, avoiding illness, managing the ups and down of stress, training consistently and in a way that stimulates various aspects of adaptations required to keep the immune system active but not over stretched.

        The better you get all these things balanced then the closer you’ll likely be able to get to your optimial performance and still maintain it decade after decade.

        Like you I feel polarised training is probably one of the best way to achieve the broad spread of stimulation required for optimimum performance for a given amount of overall stress.

        My own training for the first six months of this year was probably too dominated by low intesntiy runs, focusing on volume – it was successful at helping me do well in my ultra races but not neccessarily optimal.

        This summer I have moved across to adding more high intensity runs, in August around 20% of my runs were tempo or alternation runs, with the rest at recovery (just under 50%) or easy pace (~30%). My focus was getting in shape for a 10k, and used to running at around lactate threshold pace. I feel now that the balance wasn’t perfect as I’ve ended up getting a little too close to over training several times.

        This month I’ve shifted to training for an ultra so have reduced the faster runs to once a week and added more long runs. Alas I over stepped the mark at the weekend and injured my left calf during a 21mile run. I started the run with calfs that still had fatigue that had accumulated over the weeks, it eased off but then later pain emerged. I’m now resting up to heal the injury, which should be fine by the weekend when I’ll test it with a gentle 41 mile race 🙂

        So while I’m doing a polarised training right now, one still has to be careful and listen to the body. Doing long runs like Ed Witlock does would have probably saved me from injury – running a short loop allows you to bail out on the first sign of trouble. I was stuck ten miles from with an injured calf with only one option but to run/walk home. Thankfully it’s one the mend now so no long term damage done.

  4. Kay Says:

    Is it possible to suffer from this even though you are not an athlete but used to casually run?

    For a number of years I was on a vigorous weight loss pattern, going from severely obese to normal and losing 55kg in the process. But I also started to run and at one point was running 2-3x 13km a week. I also did some muscle strengthening in that period. That was my peak. Then my injuries mounted, tiredness crept but was still bearable. But all this was to change when one day I had a PT session that was particularly strenuous. It came at a time of relative rest. I couldn’t recover and for a period of a week to a month things got bad. Eventually I was forced to take like a month of work as I was too tired to get out of bed.

    Lots has changed since then. I am able to do more but not by much. My diet, sleep, lifestyle, all drastically changed and I take tons of supplements. But it is telling that whenever I walk or do even simple stretching exercises I get very fatigued and tired. It is as if my body has moved to permanent glycolysis. It should also be noted that I do suffer from a high degree of health fears and anxieties. Chronic fatigue was a major fear of mine, even before my issues started.

    There is no element of adrenal fatigue in the tests that we have done, but my morning and afternoon cortisol levels are very high which reflects my anxiety. Also worth noting that my tests have all shown really normal values, and we have tested everything including the Kreb’s cycle. One thing of importance is that in my later exercise period I was suffering from a very low testosterone problem (which has now been corrected) and certainly I had some deficiencies in fatty acids. Again now corrected.

    • canute1 Says:

      I am sorry to hear of the troubles you are experiencing.

      The causes of over-training syndrome and of chronic fatigue, which has many features in common with over-training, remain controversial. Therefore, my thoughts on the topic are only speculative.

      In general, I would only expect to see over-training in athletes who have been subject to substantial sustained stress, typically greater than the physical activity you describe at the time of onset of the symptoms. However, I wonder whether the long term sequelae of major weight reduction contributed to continuing stress in your situation. After large weight loss, the body sometimes remains in a state reduced basal metabolic rate for a period of years. Perhaps during a state of reduced basal metabolism, the body has reduced ability to recover from vigorous exercise. In addition, if you were continuing to limit calorie intake at the time of the strenuous PT session, that might have further impeded your ability to recover.

      Even if this speculation about factors that precipitated the problem is correct, it leaves you with a dilemma as to what to do to promote recovery at this stage. You remain at risk of a recurrence of former weight gain unless you take care to avoid excess calories. On the other hand, your body might struggle to recover from even mild exercise if you are restricting calories. You mention continuing to focus on healthy nutrition, but I wonder if you might be restricting total calories too much. It might be worth testing to see if a week of somewhat increased food intake improves your ability to recover from mild exercise – but you need to walk down a narrow path between adequate nutrition on the one hand and avoiding calorie intake that exceeds energy output on the other. And I must repeat that my thoughts are only speculation.

      • firaskay Says:

        Thank you so much for your reply and speculation. Your comments are spot on and reflect my thinking well. Having been seeing a physician who has studied sports science and has worked with fatigued patients for decades, he has ruled out both overtraining and FAMS. He reckons the problem could either be adrenal or viral, quite possibly also psychosomatic perpetuated by constant fears and anxiety. What is for certain is that I cannot go down a path of caloric restriction as you said, that is dangerous. I have gained weight, around 5 or 6 kg in the space of 10 months. Considering my sudden halting of all exercise this is not much but is enough to unnerve me as you can imagine.

        I have recently done a metabolic breathing exam and the results were unusual. It showed that my RQ is increasing at rest, thus signalling anaerobic metabolism at rest. It has also showed that my RMR is very high, around 2000kcals, which is unusual for someone who lost so much weight. This has worried my physician who has now requested we do the test on the treadmill to assess the body’s reaction to exertion. This should give us really important data on how I am responding to movement and if I am in some sort of permanent glycolysis. Both my physician and an expert running the test will attend.

        What I can tell you is that I am still petrified of gaining weight but I am not in restriction (though I ponder it), I eat well, and I have incorporated quite a substantial amount of non-inflammatory organic fats in my diet that were previously absent (ghee, coconut oil, animal fats). Carbs have gone down drastically as I have now cut out all grains including wheat. I also dont eat dairy, refined sugar or legumes. This leaves me with organic fruits, vegetables, meats and fat. I also take plenty of supplements. In short, I am paleo!

        But I still wonder if there is some underlying problem that we just haven’t found yet. I say that because I still suffer from a whole host of tendonitis pains that all this period of rest and anti-inflammatory eating didn’t resolve. Achilles, groin, pects, shoulder bursas, knee cap pains, quads. These are all issues you would get as an athlete playing day in day out. And yes I used to run loads, and some of these issues predate my chronic fatigue by a long time, I just wonder why they dont disappear. They certainly dont help the anxiety. And the catch 22 is ofcourse that for them to truly heal they do need physio work, which requires anaerobic exertion of some kind!

        In many ways, I am in the impossible place. Move, get worse. Rest, get worse.

    • canute1 Says:

      I am not sure that high RQ at rest necessarily indicates anaerobic metabolism at rest. If you were burning glucose aerobically while simultaneously converting glucose to fat, I would expect RQ would be somewhat greater than unity, because fat is a more reduced form of fuel than glucose and the conversion of glucose to fat generates CO2. A key step in the conversion or glucose to fat is the conversion of pyruvate to acetyl-CoA. This conversion generates CO2. In the next step in the synthesis of fat, the acetyl CoA combines with CO2 to produce malonyl-CoA, but the CO2 is released at later stage when malonyl-CoA is incorporated in fat, Thus, the overall balance is the production of one CO2 molecule for each carbon atom incorporated into fat. No oxygen is consumed in the conversion of glucose to fat. Thus If there is concurrent conversion of glucose to fat and aerobic oxidation of glucose to supply the basal energy needs at rest, the number of molecules of CO2 produced will exceed the number of molecules of oxygen consumed, giving an RQ greater than unity. On the other hand, a person who metabolises fat to help meet basal energy requirement would have an RQ less than unity.

      If my non-expert interpretation is correct, you need to promote greater oxidation of fat while reducing synthesis of fat at rest. Since cortisol promotes the synthesis of fat, it is possible that reducing your high levels of cortisol would help shift the balance away from fat synthesis. I would anticipate that reducing your levels of anxiety would help. I am aware that this is more easily said than done.

      Perhaps you do have an inherent tendency to lay down fat (either due to your genes or as a consequence of previous weight loss) but if you can develop the confidence that a more relaxed mental state will improve the situation, I would anticipate that you will find it easier to control your weight while consuming adequate nutrition to allow your body to repair itself. Note also that chronic high cortisol levels might also contribute to your musculo-skeletal aches and pains. Good luck.

      • firaskay Says:

        Do you know what Canute, and I am not just saying this, but in all this period and after paying so much money to do tests and see specialists and doctors, this is BY FAR the most logical, reasonable and genuinely comforting thing I have been told by anyone. And you managed to do it all in 2 simple paragraphs that both explain and instill confidence. Wow, thank you sir! I have genuinely suspected that anxiety is at fault all along but as all anxious people then I talk myself into the worst. But your assesment above is pure gold. It makes it so simple. Reduce anxiety, heal, move on.

    • canute1 Says:

      I am delighted that my comments have been helpful, and wish you every success in developing a more relaxed mental state..

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