The Capacity of the Runner to Adapt

Last Sunday, I ran 15-miles, barefoot and without breakfast. I was reminded all over again of what made me fall in love with running and want to study sports science at the age of 16 – the capacity of the human body to adapt.

I would meet great minds and mentors at the University of Limerick, one of them being PJ Smyth. PJ was a lecturer and the first I heard explain the emotions and behaviours associated with athletic injury. PJ was far more than a lecturer, he was a man of the students. He helped me and many others gain internships that would form the basis of our careers. Sadly, he passed away this week and I was reminded of a story he once told me. As a child at school, he had been running races and became fascinated by trying to figure out ways he could beat the other boys. In later years, as an academic, this led him to christen himself as a sports scientist from the age of 9.

He and I would later have conversations about the role of talent (genes) and practice (environment) in athletic performance and even when I left for England, we would exchange articles on the subject. PJ kept abreast of where every graduate of the UL sports science programme was. It wasn’t uncommon to get an email from PJ out of the blue, ‘do you know where John Murphy is these days?’. You’d have to click onto your Facebook and try guess from the photos where this lad had got to before getting back to PJ. Who will do this now? I don’t know. The loss of these subtleties in the modern world is perhaps as saddening as the passing of the man himself and all he represented. This will be the last blog for the season until September and is in memory of PJ.

Human Potential

Endurance events such as running are fascinating as they allow us to explore the limits of our potential in a very measurable way. For example, if you run a 10k; you can compare your time in minutes and seconds to the fastest human to ever cover the distance (Kenenisa Bekele, 26:17).

In my experience, skill based sports such as football or rugby require a certain set of skills and characteristics which can be trained to an extent (PJ would be interjecting here with several caveats about just how much he felt they could be trained) with an adequate skills coach.

However, even then, I’m not sure it can be developed to the same extent as an endurance event. The reason I say this is because team games require a combination of aerobic fitness, hand-eye coordination, agility etc., in addition to being able to respond  to constantly changing environments which require adequate decision making. While it can be argued that endurance running also requires these components, the fact is that once we learn the optimum movement pattern for us as individuals, we can practice it relentlessly. We may not be the greatest tactical racer of all time, but we can test the limits of our physiology.

Response to Running in the Short-Term

As muscles are repeatedly stimulated for weeks, months and years; a number of changes happen. An extensive railway network develops that can deliver far more oxygen than before. This railway network is essentially a network of blood vessels known as capillaries. These train tracks cross muscles like a complex underground transport map. The second thing that happens is that muscles grow more energy factories. This way, when the railway line delivers more oxygen, there is more factories ready to burn it and produce energy. These factories are known as mitochondria.

These two major adaptations combined are key for two reasons. A greater supply and extraction of oxygen means you can run faster for longer without getting tired. The second reason is that a greater supply of oxygen at a given pace i.e. 7-minute miles, enables to you to make better use of fat as a fuel source. This spares yours carbohydrate (glycogen) stores in the muscle and liver, meaning you can run for longer without eating.

These changes occur quite quickly, which is why people can get from couch to 5km in a matter of weeks. Muscles also respond to resistance exercise in a relatively short period of time by increasing in strength and size. Believe it or not, endurance exercise is essentially low intensity resistance training.

I have previously published changes in my own body composition in response to running (mainly weight-bearing) and triathlon (mainly non-weight bearing) training over 12 – 16 weeks. The changes in body fat and muscle mass, even in this short period, can be remarkable in some athletes, even when training is predominately non-weight bearing. These changes in muscle and fat, in the short term, are largely centered around the abdomen in men and the hips in women.

The Long Game

There are other changes that occur very gradually, over-time. Experience tells me that after about 12-months of consistent running, changes, noticeable to the naked eye, occur in leg muscle size and shape. Legs become more slender and the angle of the muscle in relation to your bone changes. Your tendons become stiffer and stronger and you become better at using your legs like coiled springs. You move very efficiently due to the repeated practice your motor nerves have had at recruiting and inhibiting muscles in the appropriate way and at the appropriate times.

People are often shocked when I reveal that I cover such distances (up to 15-miles; so far) without shoes. The principle of adaptation given long enough remains constant, even if you think it’s weird. In recent months, I’ve been using a 2-mile circuit (in the picture) composed of 1-mile beach and the other mile grass bank. The movement variability on offer means that muscle and tendon has had ample exposure to a variety of constraints which need to be overcome repetitively. The passive (fascia, connective tissue) and reflexive (sensory nerves) components of my feet are so well trained that my feet and subsequently, the rest of my legs can respond very quickly to changes in the ground. My calf muscles and achilles tendon which are heavily loaded with this type of running have become a strong, functional unit.

I have had achilles pain for some time now and so, it is counter-intuitive to run in this way, exposing the achilles to maximum load. Yet the body copes and repeats the feat, the following week. In some ways, I think by continually challenging the tendons at their maximum, I create a level of adaptation far away from failure. I suspect that there is pain arising from a portion of the tendon but the tendon on the whole is quite strong. Whether in shoes or not, the achilles is sore, so it seems sensible that it might as well be strong and sore.

The Continuum of Human Potential

The physiological processes described above make sports like running fascinating. They allow runners from the amateur to the elite to move along a continuum of human potential. The amateur runner with enough consistency can grow in likeness to the elite; the elite runner without enough consistency can grow in likeness to the amateur.

If you would like to catch up on any of the running blogs, I have provided links to the key ones below (lots more in the pipeline). Until September, enjoy your running and remember it’s not about what you can do this week but you can do over the next 6-months and beyond #consistencyisking

 Did the new shoes cause my heel pain?

‘What happened when we took the shoes from 9 well trained runners?’ A short blog to translate the science

Who best to ‘fix’ my running injury?

How much training for the sub-35 minute 10km?

The Theory of Self-Control: Key to Consistent Running?

Memory of the Boom Times making the Runner Go Bust?

HEAD-SPACE: The Difference between Running for Exercise or Training for Performance?

Beyond Stretching: Why Yoga is Good for Runners

Cross-Training for the Runner (that actually works!)

Beyond Speed: Why Runners Should Train like Sprinters

Beyond Running Economy: Why Strength & Conditioning Training is Good for Runners

The Road to Redemption: 10,000 hours of practice

How much training for the sub 34-minute 10 km?

Routine: The key to winning YOUR race before it starts