This is an excerpt from High-Performance Training for Sports-2nd Edition by David Joyce & Dan Lewindon.
By John Kiely, PhD
Senior Lecturer in Elite Performance, University of Central Lancashire
This chapter isn’t about loading schemes or recovery strategies. It offers no opinion on eccentrics or microcycling. It doesn’t care whether you squat. In relation to your preferred periodisation model, it’s blissfully ambivalent. It’s about something that runs deeper. Something that permeates everything we do as coaches. Something that influences the effectiveness of every programme we’ve ever prescribed, every session we’ve ever delivered, every technique we’ve ever taught, yet it’s something that remains ignored within our standard texts and journal articles and coaching courses.
In professions where we devote considerable time, energy, experience and expertise to devising training schemes, refining techniques, tracking and interpreting data; where we strive for weeks, months and seasons to shave off milliseconds or add on kilograms; where we invest heavily in technology, equipment and personnel, this chapter is about something that exerts an unseen, unquantifiable, but substantial role in every success and every failure. Something fundamental that we may have overlooked.
Coaches Should be Zombie Killers
Nobel Prize–winning economist and New York Times columnist Paul Krugman described dogmas that stubbornly refuse to die, despite being refuted by a mountain of evidence, as zombie ideas. Zombie ideas should be dead yet lurch along regardless, nibbling away at our brains, mindlessly oblivious to the damage they wreak. Zombie ideas roam our ideologies in marauding mobs, intolerant of doubt and innovation, bullying dissenting voices into submission. Zombie ideas don’t die because they serve a purpose. They substantiate a belief or superficially solve a problem or indulge a bias, so we allow them to lurk, overlooked and unmolested, in the dark, ego-protected recesses of our personal philosophies.
Zombie ideas flourish in realms where traditions, conventions and dogmas run deep and where clarifying science is shallow and superficial. Within coaching culture, there is one particularly influential zombie idea that is so deeply woven into the fabric of training lore that, despite clear evidence it should be laid to rest, persists. It survives, perpetuated by segregated and siloed academic disciplines and propagated by coaching conventions and educational curriculums. This is the zombie idea that physical-training loads predictably and proportionately elicit similar fitness outcomes in similar athletic populations.
We acknowledge, of course, that there’s always some degree of inter-individual variation. We acknowledge that the same training intervention does not benefit every athlete to precisely the same extent. We appreciate that nutritional and fatigue status exert some influence on training outcomes. But, practically, we do little to adapt our conventional ways of planning, delivering or evaluating training programmes to accommodate the extent of this training response diversity.
When we do discuss the problem of training response predictability, we commonly ascribe inter-individual responsiveness to genetic inheritance – a variable outside coaches’ and athletes’ control. Recently, however, an Australian study demonstrated that even when identical twins, sharing 100 per cent of their DNA, executed the same carefully controlled strength- and endurance-training programmes, training outcomes varied widely, illustrating that genetic distinctions are not the substantive drivers of inter-individual training responsiveness we previously assumed (1). But if genetics aren’t responsible for the bulk of inter-individual responsiveness, what is? More to the point, if we better understand the influencing drivers of training responsiveness, can these influences be more productively harnessed to optimise the effectiveness of athletic preparation processes?
This chapter challenges the zombie idea that physical training leads to predictable fitness outcomes and investigates whether a fuller appreciation of the deep drivers of training adaptation might empower more intelligent, informed, perceptive and – ultimately – more effective athletic preparation philosophies.
To build the case, however, we’ll have to go back to the beginning. The very beginning.
Understanding the Neuroeconomics of Human Health
Culturally, we tend to idealise the health-enhancing characteristics of less industrialised lifestyles. Yet, surprisingly, a recent study of Paraguayan hunter-gatherers, who run barefoot and eat a 100 per cent organically grown Paleo diet, found that men in the study missed 20 per cent of all hunts due to injury or illness. It’s difficult to find directly comparable health statistics in the industrialised world. We know that annual absenteeism in the United Kingdom hovers around 3 per cent for the weaker sex and closer to 2 per cent for females. We know that recreational runners succumb to overuse injuries at rates ranging upward of 70 per cent per year. But what do these observations tell us? Very little, beyond the obvious: First, the dangers of working in a concrete jungle are not equivalent to the dangers of working in the actual jungle (as an Irish evolutionary biologist might say, it’s like comparing apples and origins), and, second, regardless of whether we live in primeval forests or suburban sprawls, we are vulnerable. Every day we are exposed to risk; every day we walk in the shadow of a multiplicity of infections, diseases and injury-inducing mishaps (accidents, for example, are the leading cause of death for U.S. citizens under 45). These threats, each capable of easily and instantly excising us from the gene pool, constantly stalk us, poised to strike.
Standing between us and these ever-present dangers is an underappreciated and misunderstood alliance of complexly networked defences dispersed throughout our biological system. This alliance serves as both barrier and bouncer, protecting us from external threats and countering, calming and ejecting internal challenges: the immune system. The immune system evolved in a radically different environment than the one we live in today. The lifestyles we lead, the environments we move through, the dangers we face, the diets we consume, the diseases that kill us – all vary across epochs, ecosystems and cultures. Yet our immune system adapts and defends, regardless of whether the challenge is an unwelcome pathogen, a wound, a depression, a lacerating social insult or an intense training session. But constant, protective vigilance exerts a toll.
Most obviously, defence responses consume energy. In one classic experiment, for example, an injection of endotoxin increased adults’ metabolic rate by up to 40 per cent. Even patients suffering mild, naturally occurring fevers typically increase their metabolic rate by 13 per cent for each single-degree (oC) rise in body temperature (2). As energy stores are limited, dedicating energy to fight off one challenge ensures there is less energy available to fight off others.
Similarly, we retain, within our inner pharmacy, limited stores of the essential biochemical resources necessary to power immune responses – lymphocytes, histamines, prostaglandins, proinflammatory cytokines and so on. These stocks are expensive to maintain and fundamentally finite. Once deployed to fend off one threat, they are unavailable to fend off others and, once squandered, need time to resynthesise and replete. The clear implication is that we can’t optimally respond to multiple simultaneously or closely sequenced immunological threats.
Our limited internal reservoirs must be judiciously allocated. The defences we mount to prime and protect functionality are only adaptive when strategically distributed in an appropriately prioritised order and in the right doses. Optimal adaptation to any imposed threat, whether virulent virus or intense training session, subsequently demands that biological responses are accurately calibrated to the imposed challenge. And so, robust health depends on a long series of strategic, well-calibrated judgements and decisions. A healthy response is a ‘Baby Bear’s porridge’ phenomenon: neither too hot nor too cold, neither too much nor too little. Negotiating these trade-offs exerts very real consequences on how athletes respond, adapt, recover and perform.
Uncovering exactly why, however, requires a little more evolutionary excavation.