Cited by 89Sports Performance and TrainingSport Psychology and PerformanceCardiovascular and exercise physiology

Threats to internal validity in exercise science: A review of overlooked confounding variables

Halperin, Israel, Pyne, David B., Martin, David T.·2015·International Journal of Sports Physiology and Performance

Abstract

Internal validity refers to the degree of control exerted over potential confounding variables to reduce alternative explanations for the effects of various treatments. In exercise and sports-science research and routine testing, internal validity is commonly achieved by controlling variables such as exercise and warm-up protocols, prior training, nutritional intake before testing, ambient temperature, time of testing, hours of sleep, age, and gender. However, a number of other potential confounding variables often do not receive adequate attention in sports physiology and performance research. These confounding variables include instructions on how to perform the test, volume and frequency of verbal encouragement, knowledge of exercise endpoint, number and gender of observers in the room, influence of music played before and during testing, and the effects of mental fatigue on performance. In this review the authors discuss these variables in relation to common testing environments in exercise and sports science and present some recommendations with the goal of reducing possible threats to internal validity.

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Crossref · 10.1123/ijspp.2014-0566

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41 of 41 references verified0 citation errors · 0 not checkable

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  • The 6-12 week time frame captures initial expansion of the ribosomal pool but does not clarify longer-term plateaus in ribosomal accretion, rates of ribosomal decay, or the biological ceiling of translational capacity.

    “Although this time frame captures the initial expansion of the ribosomal pool, it does not clarify longer-term plateaus in ribosomal accretion, rates of ribosomal decay, or the actual biological ceiling of translational capacity that may be reached by elite athletes over years of training [141,216].”

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Authors
Halperin, I., Pyne, D. B., & Martin, D. T.
Affiliations
Edith Cowan University (AU)
Corresponding author
Halperin, Israel
Venue
International Journal of Sports Physiology and Performance
Published
2015-10
Volume
10
Issue
7
Pages
823-829
ISSN
  • 1555-0265 (ISSN-L)
  • 1555-0273
OpenAlex
W1995397610
Cited by
89
References
41
Citations by year
2026: 8 · 2025: 9 · 2024: 13 · 2023: 14 · 2022: 7 · 2021: 2 · 2020: 11 · 2019: 6 · 2018: 9 · 2017: 5 · 2016: 3 · 2015: 2
FWCI
6.51
Type
journal article
Language
en
Open access
closed
Locations
  • International Journal of Sports Physiology and Performance (publishedVersion)
  • PubMed (publishedVersion)
  • Edith Cowan University Research Online (Edith Cowan University) (submittedVersion)
  • University of Canberra Research Portal (submittedVersion)
Topics
  • Health Sciences › Medicine › Orthopedics and Sports Medicine › Sports Performance and Training
  • Social Sciences › Psychology › Developmental and Educational Psychology › Sport Psychology and Performance
  • Health Sciences › Medicine › Complementary and alternative medicine › Cardiovascular and exercise physiology
Keywords
internal validity, confounding variables, exercise testing, sports performance testing, test instructions, verbal encouragement, observer effect, music during exercise, mental fatigue
MeSH terms
Behavior Observation Techniques, Formative Feedback, Attention, Exercise Test, Mental Fatigue, Humans, Music, Research Design, Reproducibility of Results, Confounding Factors, Epidemiologic, Athletic Performance

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