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A Clarification of the (Mis)Use of the Term ‘Load’ in Sport and Exercise Science

Why It Is Appropriate and Scientific


  • Franco Milko Impellizzeri University of Technology Sydney
  • Annie C. Jeffries University of Technology Sydney
  • Asaf Weisman Tel Aviv University
  • Aaron J. Coutts University of Technology Sydney
  • Alan McCall University of Technology Sydney
  • Shaun J. McLaren Durham University
  • Judd T. Kalkhoven University of Technology Sydney



science, definition, operations, terminology, load, construct


A recent paper called for the abandonment of the term load (and training load) when used outside its mechanical meaning, claiming it is “unscientific” and “breaches scientific principles.” In this article, we explain why its use does not breach any scientific principles and we clarify the process of labelling, conceptualising and operationalising a construct. Training load is simply a label attributed to a higher-order construct overarching other interrelated sub-dimensions. This multi-level structure provides a framework (nomological network) to support the research process and also practical applications. Load is a word, and therefore cannot be “unscientific”. The “use” or “misuse” of words and terms entirely depends upon definitions that should be based on current understanding. Misuse occurs when a term is decontextualised or interpreted according to a unilateral perspective. The field of mechanics does not have a monopoly on the term load (or other common terms such as work, stress and fatigue), which are legitimately used in many scientific areas and with various meanings. The ‘obligation’ to rely on terms abiding by the Système International d’Unités (SI) when describing a construct is inappropriate. The SI relates to how we can measure, not describe training load; i.e., SI is relevant to its operational and not its constitutive (descriptive) definition. Discussions regarding shared and standardised descriptions and definitions are more relevant than discussions about discarding terms in sport and exercise science. Researchers (and practitioners) can continue to use the term training load as it does not breach any scientific principles.



Staunton CA, Abt G, Weaving D, Wundersitz DWT. Misuse of the term ‘load’ in sport and exercise science. J Sci Med Sport 2021

MacDonald DA, Friedman HL, Brewczynski J, et al. Spirituality as a scientific construct: testing its universality across cultures and languages. PLoS One. 2015; 10(3):e0117701.

Sven Ove H. "Science and Pseudo-Science". In: Zalta EN, ed. The Stanford Encyclopedia of Philosophy Fall edition 2021.

Knuttgen HG, Kraemer WJ. Terminology and Measurement in Exercise Performance. J Strength Cond Res 1987; 1(1):1-10.

Faulkner JA. Terminology for contractions of muscles during shortening, while isometric, and during lengthening. J Appl Physiol 2003; 95(2):455-459.

Vessonen E. Conceptual engineering and operationalism in psychology. Synthese 2021.

Hoy WK. Concepts, variables, and research problems. Quantitative Research in Education: A Primer. Thousand Oaks, California: SAGE Publications, Inc.; 2010.

Reznick JS. Defining Constructs and Variables, in The Developmental Scientist's Companion: Improving Research Methodology and Achieving Professional Success. Reznick JS, ed^eds. Cambridge, Cambridge University Press, 2017.

Markus KA. Constructs, Concepts and the Worlds of Possibility: Connecting the Measurement, Manipulation, and Meaning of Variables. Measurement 2008; 6(1-2):54-77.

Bhattacherjee. Social Science Research: Principles, Methods and Practices, 2012.

Stenner AJ, Smith M, Burdick DS. Toward a Theory of Construct Definition. J Educ Meas 1983; 20(4):305-316.

Middendorp CP. On the conceptualization of theoretical constructs. Qual Quant 1991; 25(3):235-252.

Willer D, Webster M. Theoretical Concepts and Observables. Am Sociol Rev 1970; 35(4):748-757.

Chalmers DJ. What is conceptual engineering and what should it be? Inquiry 2020:1-18.

Cappelen H. Fixing Language. An Essay on Conceptual Engineering. Oxford: Oxford University Press 2018.

D'Amico D, Amestoy ME, Fiocco AJ. The association between allostatic load and cognitive function: A systematic and meta-analytic review. Psychoneuroendocrinology 2020; 121:104849.

Naismith LM, Cavalcanti RB. Validity of Cognitive Load Measures in Simulation-Based Training: A Systematic Review. Acad Med 2015; 90(11 Suppl):S24-35.

Adamczyk AK, Ligeza TS, Wyczesany M. The dynamics of pain reappraisal: the joint contribution of cognitive change and mental load. Cogn Affect Behav Neurosci 2020; 20(2):276-293.

Jenkins DJA, Dehghan M, Mente A, et al. Glycemic Index, Glycemic Load, and Cardiovascular Disease and Mortality. N Engl J Med 2021; 384(14):1312-1322.

Cooper LL, Rong J, Benjamin EJ, et al. Components of hemodynamic load and cardiovascular events: the Framingham Heart Study. Circulation 2015; 131(4):354-361; discussion 361.

Lopman BA, McQuade ETR. Using viral load to model disease dynamics. Science 2021; 373(6552):280-281.

Potteiger JA. American College of Sports Medicine’s introduction to exercise science, Third edition ed, Philadelphia, Wolters Kluwer Health; 2018.

Murphy G, Groeger JA, Greene CM. Twenty years of load theory—Where are we now, and where should we go next? Psychon Bull Rev 2016; 23(5):1316-1340.

Sweller J. CHAPTER TWO - Cognitive Load Theory, in Psychology of Learning and Motivation. Mestre JP, Ross BH, ed^eds, Academic Press, 2011.

Boring EG. The use of operational definitions in science. Psychol Rev 1945; 52(5):243-245.

Slife BD, Wright CD, Yanchar SC. Using Operational Definitions in Research: A Best-Practices Approach. J Mind Behav 2016; 37(2):119-139.

Stevens SS. The Operational Basis of Psychology. Am J Psychol 1935; 47(2):323-330.

Law KS, Wong C-S, Mobley WH. Toward a Taxonomy of Multidimensional Constructs. Acad Manage Rev 1998; 23(4):741-755.

Olsen JA, Misajon R. A conceptual map of health-related quality of life dimensions: key lessons for a new instrument. Qual Life Res 2020; 29(3):733-743.

Lang JJ, Smith JJ, Tomkinson GR. Global Surveillance of Cardiorespiratory and Musculoskeletal Fitness. In: Brusseau TA, Fairclough SJ, Lubans DR, eds. The Routledge Handbook of Youth Physical Activity. Abingdon: Routledge; 2020.

Committee on Fitness Measures and Health Outcomes in Youth, Food and Nutrition Board, Institute of Medicine. Health-Related Fitness Measures for Youth: Musculoskeletal Fitness. In: Pate R, Oria M, Pillsbury L, eds. Fitness Measures and Health Outcomes in Youth. Washington (DC): National Academies Press (US); 2012.

Cronbach LJ, Meehl PE. Construct validity in psychological tests. Psychol Bull 1955; 52(4):281-302.

McLaren SJ, Macpherson TW, Coutts AJ, Hurst C, Spears IR, Weston M. The Relationships Between Internal and External Measures of Training Load and Intensity in Team Sports: A Meta-Analysis. Sports Med 2018; 48(3):641-658.

Giere RN. Understanding Scientific Reasoning, Holt, Rinehart, and Winston; 1991.

Cohen ER, Cvitas T, Frey J, et al. Quantities, Units and Symbols in Physical Chemistry, IUPAC Green Book, 2007.

Liguori G, Medicine ACoS. ACSM's guidelines for exercise testing and prescription, Lippincott Williams & Wilkins; 2020.

Committee PAGA. 2018 Physical Activity Guidelines Advisory Committee Scientific Report: Washington, DC; 2018.

Plavén-Sigray P, Matheson GJ, Schiffler BC, Thompson WH. The readability of scientific texts is decreasing over time. Elife 2017; 6:e27725.