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Training Load: Science or Semantics?

Recently, a pre-print paper was shared on social media that received a notable reaction from the online sports science community. That paper was “Misuse of the term ‘load’ in sport and exercise science” by Craig Staunton, Grant Abt, Dan Weaving, and Daniel Wundersitz in the Journal of Science and Medicine in Sport, which can be accessed here. The authors postulate that the use of terms load and training load breach “principles of science” and should be abandoned.


There was quite a “Marmite” response to the messages on social media (as to be expected on social!); some applauding the concerns raised, and others questioning the relevance and/or the alternative approach proposed. As is often the case, the discussion is not necessarily binary, so let’s try to recognise and explore the nuance within the arguments.


It is, of course, important to read the paper in full rather than building an opinion purely on the title, abstract, or a 140-character tweet. So as a reminder, the open-access pre-proof is available here.


But First, A Note on Rethinking

When consuming the paper, it is important to approach it with an open mindset. Load is a divisive term in many ways in our field, illustrated by debates on calculations, as well as the applications we can and cannot use training load data for. It is easy (and perhaps natural) to broach this editorial with a bias viewpoint, especially as the title could be taken as accusatory (i.e. “misuse").


I’ve previously cited Adam Grant’s brilliant book, Think Again, in relation to the benefits of perspective seeking rather than perspective taking. Throughout that book, Grant encourages his readers to think like scientists, because it is a profession in which rethinking is fundamental. It is important that we do not lose sight of that within our own experiences and biases. So let’s delve into this paper and consider if we should indeed rethink the use of the term load.


The “Misuse” of Scientific Terms

This paper is inspired by previous work by the late Professor Edward Winter, including an editorial entitled "Workload"-- time to abandon? and another called “Misuse of “power” and other mechanical terms”. Based on the argument that mechanical nomenclature, most notably work and power, are being misused in sports science, this new editorial expands this discussion to the terminology of load and training load in light of recent research in this area.


At the core of the argument for Staunton and company is that, as scientists, we are bound by the International System of Units (SI; from French Système international (d'unités)). According to the SI, work is the product of distance through which a force (N) is applied and is presented in joules (J). While, Winter and colleagues (2015) suggested that load refers to the resistance experienced during the performed work and therefore, is a force with the units of Newtons (N).


Yet, despite the claim that the term workload is therefore, “nonsensical” and should be eliminated from the literature, this term continues to be common both in the academic and applied sports science lexicon.


Varying Definitions of ‘Load’

Multiple definitions of load from across scientific disciplines are listed in the paper, including engineering and electrical physics, as well as non-scientific definitions given in the Oxford English dictionary. The authors argue that this array of definitions is problematic.


However, in my opinion, this in itself highlights the varied used of the term load, which have many definition across our language. Load is not solely a mechanical word describing a force nor, in fact, is it purely a scientific word. It is not proprietary to the field of mechanics. In fact, the most pertinent use of the term in recent times is probably viral load!


There are varying definitions, both scientific and non-scientific constructs, that can each construe a valid meaning. The given example of “she has a heavy teaching load” does not present a comprehension issue, and would be understood just the same as their proposition of “she has a heavy teaching burden”.


An Obligation to SI?

That said, I recognise that we should focus on the scientific definitions and uses, rather than popular terminology. The authors state that the “terms and nomenclature used to describe exercise should abide by the Système International d'Unités”. The SI is an internationally agreed set of standard units. There are 7 fundamental units – length, mass, time, electric current, temperature, luminous intensity, and matter – from which multiple derived units can also be determined, including force in N and power in Watts (W). Therefore, it is a system of measurement, each with an assigned unit of measurement and does not seek to control the definition of various terminology.


Furthermore, it is based on the metric system. This is understandable in formal laboratory and publication settings. However, in the applied setting we cannot be bound solely to this system. Try telling weight rooms across American that they need to change their measures of mass from pounds to kilograms in order to abide by the SI… (I tried it for my own benefit and it doesn’t work!!)


Finally, the focus on the SI seems to highlight some inconsistency with the proposal. In line with the American College of Sports Medicine’s (ACSM) suggestions, the measures of (exercise) volume and frequency are recommended as an alternative to training load. This despite their inclusion in the SI, with volume assigned to the unit of cubic metres (m3) and frequency measured in hertz (Hz), not to mention the representation of intensity as one of the same units of SI as luminous intensity.


The Complex Reality of Training Load

Training load is a complex construct. It includes both internal and external dimensions, which are each determined by a combination of both volume and intensity. The validity of measures that seek to capture constituent parts of the overall load differ depending on a host of factors. Inter-individual response to training load is highly variable. Inconsistencies exist due to this complex nature. A single measure will likely never fully encapsulate training load as a whole, which is why multivariate approaches are consistently recommended.


Personally, I disagree with the statement that “scientists have no conceptual or analytical requirement to amalgamate separate training constructs (intensity, frequency, duration)”. As I previously discussed for Rob Pacey on Sportsmith, practitioners face the challenge of report as few metrics as possible but not so few that meaning is lost. This need to reduce training load data for key stakeholders places an even greater responsibility on the practitioner to understand the underlying complexity, calculations, and limitations of the data they disseminate.


I agree with the authors’ concern regarding the breadth and reductionist use of the term training load. Some parties, whether through deliberate deception or just ignorance, may use training load in an overly simplistic or ambiguous nature. As scientists, we should strive for greater clarity and understanding, not just in what we mean by load but also what others, particularly sports technology and data companies, refer to and how they have determined such measures.


Getting on the Same Page About Training Load

Many responses to the editorial emphasised the importance of communication and education, over and above the vernacular used. For example, Jose Fernandez argues that the priority is ensuring the coaches can understand and action the information provided.

Obviously I cannot reiterate enough the importance of communication in getting on the same page with colleagues and athletes to work in an integrated manner. Correcting terminology used by others to meet scientific standards will most probably not serve this purpose well in the applied environment.


However, open and ongoing discussion about what we mean by certain terminology is important. What does training load mean to the coach, athlete, physio/PT/AT, strength and conditioning/fitness coach? Can we continue to educate on the complexity of this construct while appreciating we need to provide as few measures as possible on a daily report or conversation in order to summarise it? Similarly, what do other constructs of speed, fitness, athleticism etc. mean in your sport, your environment, and to your colleagues? Do we understand the perspectives of our colleagues and athletes when we each use such terminology?


Semantics or Scientific?

Discussion and discourse is part of the scientific process. I welcome both the viewpoint of the authors and the debate it has sparked. Is the term ‘load’ misused in sports and exercise science? In my opinion, yes, in some settings and circumstances. Does that mean we should immediately stop using it? In my humble opinion, no.


The terminology we use is important. We recently discussed how using practical and accessible language, such as the so-called “worst-case scenario”, can be appealing, but there remains a danger of being too simplistic. As scientist, it is essential we recognise the underlying complexity and understand the potential downsides of interventions we propose. We should show curiosity when our athletes, coaches, and colleagues discuss training load, while meeting those claiming to measure or calculate load with scepticism and further enquiry.


This publication has given me the opportunity to review the terminology of training load with a beginner’s mind and reflect upon what we are attempting to measure. While it did not convince me at this time to abandon the use of the terminology of training load, the opportunity to change our minds, especially as scientists, should be a welcome one. It is that very process – updating our beliefs based on new evidence – that we will explore in the next post…