Transformation through Adaptation
Article by Professor Jon Patricios – sports physician and contributor to Comrades Panel Talks for over 12 years. Archived material from the Comrades Panel Talks, hosted by the late Don Oliver.
Introduction
I interact with Comrades runners almost every day in my clinics. Unfortunately, the circumstances of our meeting are seldom pleasant, but usually centre on diagnosing and managing an injury or medical problem that has arisen around training and has the potential to threaten a Comrades dream. I have given much thought to the range of diagnoses I encounter and crystallised in my own mind the reasons for injury or conditions associated with running to try and enable me to incorporate a preventative strategy in my management thereof and, importantly, to educate other runners. My talks to runners and advice to would-be participants have therefore deliberately been more sobering than spirited. I do not wish to dampen enthusiasm but rather place expectations in a realistic context and to encourage an understanding of what is happening to the body of the novice runner.
There is a good reason why most Comrades training programmes begin in January, if not in November of the previous year. It hinges around that great South African term ‘transformation’, not in its political sense (a topic for another Comrades article) but in the context of the process of change occurring to the runner’s body. This is by nature an evolutionary process that, in the novice in particular, takes time. Failure to acknowledge this leads not only to failure but injury too.
Adaptation
The key ‘take home’ term as far as I am concerned is ‘adaptation’. This to me summarises the body’s response to the challenge of exercise. To adapt means ‘to change something to suit different environments and conditions’. Especially for the novice, running nearly 90 kilometres certainly represents ‘different conditions’. The process of what we refer to as ‘getting fitter’ is nothing more than exposing the body to stresses not faced before and allowing adaptation of various systems within the body to improve the chances of success.
What we perhaps overlook is the complexity of this process. It is a process that involves changes to the heart as much as to the hormones, the bones as much as the blood and the muscles as much as the mind. This multi-system adaptation progression looks after itself as long as one follows a programme that stresses each system in digestible amounts – the ‘bite able bits’ and ‘chewable chunks’ of training that I often heard Don Oliver refer to. Certain training sessions stretch these systems, something we refer to as ‘overreaching’, whilst others must allow for recovery.
The Systems
Musculoskeletal – Muscles and Bones
The muscles involved in driving us along the road are referred to as skeletal muscles, that is, muscles attached to the skeleton. At a microscopic level we have different types of muscle, ‘slow twitch’ fibres that facilitate more the long slow distance exercise associated with ultra-marathons and 2 subtypes of ‘fast twitch’ fibres favoured by sprinters that will probably only be of use in a dash to the finish line at 5.30pm. We all have both types, but the more efficient endurance athletes probably have a preponderance of slow twitch fibres. These are better at using oxygen and alternative sources of energy, including fat to drive the body. In addition, via persistent exposure to endurance exercise, certain fast twitch fibres may alter their characteristics to become more fatigue resistant. Changes occurring in these muscle cells with training include an increase in their size, improved oxygen storage capacity and improved energy production in the cells’ ‘powerhouses’.
Bones have an equally important role in adapting to the stress of exercise. The most beneficial change in running is that of increased bone mineral density, in other words the bones become stronger. This is often quoted as being one of the advantages of running over sports in which one does not carry all one’s body weight such as cycling or swimming. The changes occur as the legs in particular are exposed to stresses well beyond those of daily living. Gradual and ongoing exposure will lead to stronger bones whilst too large a running load too early on or too great a load for too long may lead to injury. Some of these gains are also lost when exercise is stopped.
Oxygen Transport System
Rather than discuss the lungs, heart, blood vessels and other aspects of oxygen transport separately, I feel that it is more appropriate to view these as one system, as all aspects are so intimately intertwined. Endurance running is an ‘oxidative process’, in other words, we require oxygen to be taken in and delivered efficiently to the muscles to generate energy.
Many people often refer to an efficient athlete as having ‘good lungs’. In fact, there is little that we can do to enhance our lung capacity which is largely determined by genetics. We can improve the efficiency of our breathing but this is largely a reflection of muscular changes, and we can certainly do much to diminish the extent of the lung interface with the atmosphere through smoking and pollution damage.
The heart on the other hand is one of the great physiological ‘adapters’. In essence, the heart functions as a pump that moves blood around the body carrying oxygen and nutrients to where they need to be and removing waste products. The larger the capacity of the pump, the more efficiently it will perform this function. Because it is made up of muscle, the adaptations to exercise occur efficiently and relatively quickly. Thicker muscle allows for more blood to be pumped with every contraction. Hence athletes’ hearts are bigger than non-athletic individuals and, because they pump more efficiently, they contract fewer times per minute, accounting for the lower pulse rate of ‘fit’ individuals.
Additional improvements in oxygen transport include an increase in oxygen transport due to raised haemoglobin (the protein that binds oxygen in the blood) concentrations, increased number of fine blood vessels that permeate into muscle fibres to deliver the oxygen and a hormonally governed ‘shunting’ of blood away from systems perceived to be less important for running such as the gut, to the skeletal muscles. To avoid the blood becoming too ‘thick’ with increased haemoglobin, the volume of the blood is also increased in athletes to allow for more efficient blood flow and oxygen transport.
Oxygen Utilisation
Just as oxygen is efficiently delivered to the muscles, it should also be better utilised. This is facilitated by an increase in the number of capillaries delivering oxygen to muscle cells as well as higher concentrations of myoglobin protein within muscle fibres that allow for oxygen to be offloaded into the cells where they are needed.
The most well-known measure of both oxygen delivery and oxygen utilization is VO2 max. This refers to the maximum rate at which the body can consume oxygen at its maximum work rate. It is probably more influenced by improvements in oxygen delivery and can be improved particularly in runners starting from a low fitness base. In the greater context of Comrades training however, the measurement or prediction of V02max is not that important.
In summary then, athletes training for the Comrades
Marathon can expect the following changes:
• A heart that pumps blood and oxygen more efficiently
• Better delivery of oxygen and nutrients via blood vessels
• Muscle cells that take up more oxygen
• Improved breathing
• Stronger bones
• Better energy generation, storage and utilization
What is more challenging and often not realised is that each of these systems adapts at a different rate. The heart and cardiovascular system is relatively quick at making improvements, the bones and some soft tissues such as tendons much slower.
Injury
Injury is part of sport and something I see a lot of. Injury is nothing more than a failure of the affected area of the body to adapt to the stress of exercise. Either the body part is too weak or the exercise load too much or a combination of both. Due to the differing adaptation rates of various body parts, it is not unusual to see an increase in bone and soft tissue injuries six to 10 weeks after a runner embarks on a training programme. The cardiovascular adaptations are so efficient that the runner feels capable of increasing mileage significantly, but the skeletal structures are just not ready for that load and break down.
Typical examples include bone stress fractures, Achilles tendinopathy (commonly referred to as ‘tendinitis’) and muscle strains.
The Immune System
The body’s ability to fight off infections especially the common cold and other viruses is certainly influenced by exercise. Research shows that the gradual introduction of a low to moderate intensity training programme will boost the immune system. The opposite is true when one exposes the body to high intensity exercise or long sessions that the body is not used to. The latter part of Comrades training involving longer distances, often undertaken on colder autumn mornings in groups all breathing heavily, may be just the cocktail for a lingering respiratory tract infection.
The key to preventing such illnesses as well as injuries is to periodise training. Periodisation refers to the frequency of exercise, the intensity of the sessions, the duration of the runs and the extent of ‘overload’ (how much further or harder is this session than you are used to?). It implies breaking your schedule into periods of harder and easier training, periods of exertion and periods of rest. The physiological reasoning behind this is that your body actually breaks down during long and hard runs and requires periods of low intensity and, very importantly, rest from running, to be able firstly to recover and secondly, to make the necessary adaptations to be able to cope with the stress better next time.
‘You get fitter whist resting’ is a maxim that I am fond of using to emphasise this point. Thus, any reputable training programme will have rest days and easier weeks built in as well as the longer and more challenging runs.
It is also prudent to remember that running is not the only stress with which your body has to cope. Illness over the pre-Comrades period may mean that your body is not only unable to adapt efficiently, but you may do yourself harm by training. Allowing your body to recover will have a far more beneficial effect on your fitness. Emotional and work stresses may have a similar impact.
The ultimate Comrades tragedy – death during the race, of which we have seen a few examples in recent years, usually results either from athletes competing with an illness or being significantly under-trained so that all of their major systems are poorly adapted to the stress of the ultra-marathon. In fact, for novices 40 years of age or over, or those with a known family or personal history of heart disease, a medical assessment before embarking on an endurance programme is recommended.
There are other interventions which may hinder our bodies’ ability to adapt. These include inadequate nutrition (especially after every training session), inappropriate hydration (especially being tempted to drink too much during a run) and the use of medication, especially painkillers and anti-inflammatories which may compromise gut and kidney function.
Conclusion
Your body will transform into that of a Comrades runner through adaptation. The programmes presented here are structured to accommodate due physiological processes. These being that the body requires controlled doses of exposure to exercise stress, that different systems adapt at different rates, that you periodise using longer runs and shorter sessions, and that rest is an important part of this process.