Big words, thought provoking logic!
The first principles of exercise have been taught to students of physical education and exercise sciences for decades, primarily to guide the logic of exercise programme design. For a refresher on those first principles see this blog More, More, More. My educational roots are those tenets, and they have been my guiding lights through stints in exercise, rehabilitation, strength and conditioning, and academia. While still holding them in high regard, I have come to realise that they come with a strong physiological bias and conveniently discount many other determinants of exercise outcomes. Experience and a bit of common sense have shown me that the first principles of exercise are highly fallible and unlikely to be universally applicable.
There are many things about exercise responses and adaptations – many more than we probably like to think – that we simply do not know. Yet we happily ignore that absence of evidence and carry on with our assumptions. Consider for a moment that a common belief is that strength and conditioning practices help prevent injury. Now, I do not know of any studies that have actually demonstrated this – after all, how could they? There are simply too many factors influencing injury that make such an assumption and proof impossible. Maybe strength and conditioning actually increases injury risk! Just try convincing the strength and conditioning world of that!
With honest reflection on experiences it becomes hard to overlook the discrepancies between theory and reality. I chose not to notice that similar programmes seemed to provoke different adaptations in different individuals, and that different individuals seemed to be accomplishing similar fitness adaptations in different ways. I understood that there was a principle of individual differences, but I had still had stubborn faith in the structure of my programmes!
Then I came across Pol et al’s (2020) paper that methodically explores some of those issues. They use the word ‘degeneracy’ to describe the multiple ways that similar outcomes can be achieved. The term is intended to describe the ability of elements that are structurally different to perform the same function or yield the same output (Edelman & Gally, 2001). In our context, degeneracy is the idea that different programming elements and structures can have similar outcomes. We know that right? Individuals can get stronger following different regimes; gymnasts do so through body weight exercises and lots of repetition, rugby players through few lifts of heavy weights. At the individual level those differences can be even more profound. To ’bookend’ that shift in thinking, another term ‘pleiotropy’ suggests that a particular stimulus can have multiple influences and different outcomes. So the exact same exercise programme may produce different individual effects and outcomes. What appears to be a programme for aerobic conditioning may stimulate aerobic benefits in some, but for others the effect may be more muscular endurance than cardiorespiratory. The concept of pleiotropy contends that the stimulus influence will affect multiple organ systems, and the exact weighting may be beyond the control of the exercise prescriber. We follow the principle of progressive overload to design an exercise stress to target an organ system, but identical programmes could provoke different individual effects and outcomes.
You can sense how the ‘slipperiness’ of pleitropy and degeneracy can confound a lot of practice and research (Paaby & Rockman, 2013). The lack of consistency of responses may be disarming, but I kind of like it! I like the idea that the exercise principles guide us on how to provoke exercise responses and longer term adaptations, but we need to be vigilant, reflective and thinking critically, knowing that an exercise stimulus is unlikely to produce a highly predictable response. I think we should embrace that chaos and know that through experience, contemplation and trial and error, we can effect the kind of changes that we are seeking. Another great reason why our exercise experts need to be well educated, open minded, critical thinkers.
References for your interest
Edelman, G.M., Gally, J.A. Degeneracy and complexity in biological systems. Proc Natl Acad Sci U S A. 2001 Nov 20;98(24):13763-8.
Paaby, A. B., & Rockman, M. V. (2013). The many faces of pleiotropy. Trends in genetics, 29(2), 66-73.
Pol, R., Balagué, N., Ric, A., Torrents, C., Kiely, J., Hristovski, R. (2020) Training or Synergizing? Complex Systems Principles Change the Understanding of Sport Processes. Sports Medicine – Open 6:28