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Jacques M, Landen S, Romero JA, Yan X, Hiam D, Jones P, Gurd B, Eynon N, Voisin S. Implementation of multiple statistical methods to estimate variability and individual response to training. Eur J Sport Sci 2022; 23:588-598. [PMID: 35234572 DOI: 10.1080/17461391.2022.2048894] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
HIGHLIGHTS What are the findings? We implemented five statistical methods in a single study to estimate the magnitude of within-subject variability and quantify responses to exercise training at the individual level.The various proposed methods used to estimate individual responses to training provide different types of information and rely on different assumptions that are difficult to test.Within-subject variability is often large in magnitude, and as such, should be systematically evaluated and carefully considered in future studies to successfully estimate individual responses to training. How might it impact on clinical practice in the future? Within-subject variability in response to exercise training is a key factor that must be considered in order to obtain a reproducible measurement of individual response to exercise training. This is akin to ensuring data is reproducible for each subject.Our findings provide guidelines for future exercise training studies to ensure results are reproducible within participants and to minimize wasting precious research resources.By implementing five suggested methods to estimate individual response to training, we highlight their feasibility, strengths, weaknesses, and costs, for researchers to make the best decision on how to accurately measure individual responses to exercise training.
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Affiliation(s)
- Macsue Jacques
- Institute for Health and Sport (iHeS), Victoria University, Melbourne, Australia
| | - Shanie Landen
- Institute for Health and Sport (iHeS), Victoria University, Melbourne, Australia
| | | | - Xu Yan
- Institute for Health and Sport (iHeS), Victoria University, Melbourne, Australia
| | - Danielle Hiam
- Institute for Health and Sport (iHeS), Victoria University, Melbourne, Australia.,Deakin University, Geelong, Australia, Institute for Physical Activity and Nutrition (IPAN), School of Exercise and Nutrition Sciences
| | - Patrice Jones
- Institute for Health and Sport (iHeS), Victoria University, Melbourne, Australia
| | - Brendon Gurd
- School of Kinesiology and health studies, Queen's University, Kingston, ON
| | - Nir Eynon
- Institute for Health and Sport (iHeS), Victoria University, Melbourne, Australia
| | - Sarah Voisin
- Institute for Health and Sport (iHeS), Victoria University, Melbourne, Australia
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Individual Participant Data Meta-Analysis Provides No Evidence of Intervention Response Variation in Individuals Supplementing With Beta-Alanine. Int J Sport Nutr Exerc Metab 2021; 31:305-313. [PMID: 34098531 DOI: 10.1123/ijsnem.2021-0038] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Revised: 04/05/2021] [Accepted: 04/05/2021] [Indexed: 11/18/2022]
Abstract
Currently, little is known about the extent of interindividual variability in response to beta-alanine (BA) supplementation, nor what proportion of said variability can be attributed to external factors or to the intervention itself (intervention response). To investigate this, individual participant data on the effect of BA supplementation on a high-intensity cycling capacity test (CCT110%) were meta-analyzed. Changes in time to exhaustion (TTE) and muscle carnosine were the primary and secondary outcomes. Multilevel distributional Bayesian models were used to estimate the mean and SD of BA and placebo group change scores. The relative sizes of group SDs were used to infer whether observed variation in change scores were due to intervention or non-intervention-related effects. Six eligible studies were identified, and individual data were obtained from four of these. Analyses showed a group effect of BA supplementation on TTE (7.7, 95% credible interval [CrI] [1.3, 14.3] s) and muscle carnosine (18.1, 95% CrI [14.5, 21.9] mmol/kg DM). A large intervention response variation was identified for muscle carnosine (σIR = 5.8, 95% CrI [4.2, 7.4] mmol/kg DM) while equivalent change score SDs were shown for TTE in both the placebo (16.1, 95% CrI [13.0, 21.3] s) and BA (15.9, 95% CrI [13.0, 20.0] s) conditions, with the probability that SD was greater in placebo being 0.64. In conclusion, the similarity in observed change score SDs between groups for TTE indicates the source of variation is common to both groups, and therefore unrelated to the supplement itself, likely originating instead from external factors such as nutritional intake, sleep patterns, or training status.
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Bonafiglia JT, Islam H, Preobrazenski N, Ma A, Deschenes M, Erlich AT, Quadrilatero J, Hood DA, Gurd BJ. Examining interindividual differences in select muscle and whole-body adaptations to continuous endurance training. Exp Physiol 2021; 106:2168-2176. [PMID: 33998072 DOI: 10.1113/ep089421] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Accepted: 05/12/2021] [Indexed: 11/08/2022]
Abstract
NEW FINDINGS What is the central question of the study? Do interindividual differences in trainability exist for morphological and molecular skeletal muscle responses to aerobic exercise training? What is the main finding and its importance? Interindividual differences in trainability were present for some, but not all, morphological and molecular outcomes included in our study. Our findings suggest that is inappropriate, and perhaps erroneous, to assume that variability in observed responses reflects interindividual differences in trainability in skeletal muscle responses to aerobic exercise training. ABSTRACT Studies have interpreted a wide range of morphological and molecular changes in human skeletal muscle as evidence of interindividual differences in trainability. However, these interpretations fail to account for the influence of random measurement error and within-subject variability. The purpose of the present study was to use the standard deviation of individual response (SDIR ) statistic to test the hypothesis that interindividual differences in trainability are present for some but not all skeletal muscle outcomes. Twenty-nine recreationally-active males (age: 21±2 years; BMI: 24±3; VO2 peak: 45±7 mL/kg/min) completed four weeks of continuous training (REL; n = 14) or control (CTRL; n = 15). Maximal enzyme activities (citrate synthase and β-HAD), capillary density, fibre type composition, fibre-specific SDH activity and substrate storage (IMTG and glycogen), and markers of mitophagy (BNIP3, NIX, PRKN, and PINK1) were measured in vastus lateralis samples collected before and after the intervention. We also calculated SDIR values for VO2 peak, peak work rate, and the onset of blood lactate accumulation for REL and a separate group that exercised at the negative talk test (TT) stage. Although positive SDIR values - indicating interindividual differences in trainability - were obtained for aerobic capacity outcomes, maximal enzyme activities, capillary density, all fibre-specific outcomes, and BNIP3 protein content, the remaining outcomes produced negative SDIR values indicating a large degree of random measurement error and/or within-subject variability. Our findings question the interpretation of heterogeneity in observed responses as evidence of interindividual differences in trainability and highlight the importance of including control groups when analyzing individual skeletal muscle response to exercise training. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Jacob T Bonafiglia
- School of Kinesiology and Health Studies, Queen's University, Kingston, Ontario, Canada
| | - Hashim Islam
- School of Kinesiology and Health Studies, Queen's University, Kingston, Ontario, Canada.,School of Health and Exercise Sciences, University of British Columbia - Okanagan, Kelowna, BC, Canada
| | - Nicholas Preobrazenski
- School of Kinesiology and Health Studies, Queen's University, Kingston, Ontario, Canada.,Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada
| | - Andrew Ma
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada
| | - Madeleine Deschenes
- School of Kinesiology and Health Studies, Queen's University, Kingston, Ontario, Canada
| | - Avigail T Erlich
- Muscle Health Research Centre, School of Kinesiology and Health Science, York University, Toronto, Ontario, Canada
| | - Joe Quadrilatero
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada
| | - David A Hood
- Muscle Health Research Centre, School of Kinesiology and Health Science, York University, Toronto, Ontario, Canada
| | - Brendon J Gurd
- School of Kinesiology and Health Studies, Queen's University, Kingston, Ontario, Canada
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Padilla J, Leary E, Limberg JK. Identifying responders versus non-responders: Incorporation of controls is required for sound statistical inference. Exp Physiol 2020; 106:375-376. [PMID: 33215745 DOI: 10.1113/ep089142] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2020] [Accepted: 11/18/2020] [Indexed: 12/22/2022]
Affiliation(s)
- Jaume Padilla
- Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, MO, USA.,Dalton Cardiovascular Research Center, University of Missouri, Columbia, MO, USA
| | - Emily Leary
- Department of Orthopaedic Surgery, University of Missouri, Columbia, MO, USA.,Thompson Laboratory for Regenerative Orthopaedics, University of Missouri, Columbia, MO, USA
| | - Jacqueline K Limberg
- Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, MO, USA
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