Research into Resistance Training Response Heterogeneity: a Summary of the 2025 Conference at the University of Jyväskylä

The Inter-Individual Variation in Resistance Training Response Conference was hosted at the University of Jyväskylä, Finland November 19-21, 2025. This paper summarizes key themes that emerged across lectures and discussions. First, resistance training induces multi-dimensional adaptations at the tissue, muscle fiber, and ultrastructural levels, including radial muscle fiber hypertrophy through increased myofibril number, longitudinal growth through sarcomere addition throughout the length (not ends) of muscle fibers, and metabolic adaptations that emulate other models of rapid cell growth. Second, training program variables including weekly sets, volume-load, rest interval duration, and training proximity to failure meaningfully influence hypertrophic outcomes in the general population, whereas exercise selection can be flexible. Third, age as well as molecular signatures prior to and in response to training influence inter-individual response heterogeneity. Finally, while inter-individual variability in observed hypertrophic responses is considerable, delineating true inter-individual variability from random variation remains challenging. Hence, study design considerations that can be thoughtfully applied to enhance rigor include repeat validation trials, unilateral within-subject designs, minimum clinically important difference thresholds, and multivariate composite responder classifications. This paper aims to summarize conference highlights while also providing meaningful implications for both researchers and practitioners and advancing current thinking on heterogeneity in the resistance training response.

Authors

Institutions

Publication Details

Journal
Journal of Applied Physiology
Published
2026-05-22
DOI
https://doi.org/10.1152/japplphysiol.00289.2026
Primary Topic
Cardiovascular and exercise physiology
Type
article
Field-Weighted Citation Impact
0.00

Funders

Controls
|||
ALL TIME
JAN
FEB
MAR
APR
MAY
JUN
JUL
AUG
SEP
OCT
article

Research into Resistance Training Response Heterogeneity: a Summary of the 2025 Conference at the University of Jyväskylä

Anne Hecksteden, A. Mackey, Gustavo A. Nader, Juha P. Ahtiainen et al.
Journal of Applied Physiology
Cardiovascular and exercise physiology
article

Research into Resistance Training Response Heterogeneity: a Summary of the 2025 Conference at the University of Jyväskylä

Anne Hecksteden, A. Mackey, Gustavo A. Nader, Juha P. Ahtiainen, Elina Sillanpää, Wim Derave, Juha J. Hulmi, P Atherton, Cleiton A. Libardi, Troy A. Hornberger, Stuart M. Phillips, Marcas M. Bamman, Michael D. Roberts, Brad J. Schoenfeld
article en

Abstract

The Inter-Individual Variation in Resistance Training Response Conference was hosted at the University of Jyväskylä, Finland November 19-21, 2025. This paper summarizes key themes that emerged across lectures and discussions. First, resistance training induces multi-dimensional adaptations at the tissue, muscle fiber, and ultrastructural levels, including radial muscle fiber hypertrophy through increased myofibril number, longitudinal growth through sarcomere addition throughout the length (not ends) of muscle fibers, and metabolic adaptations that emulate other models of rapid cell growth. Second, training program variables including weekly sets, volume-load, rest interval duration, and training proximity to failure meaningfully influence hypertrophic outcomes in the general population, whereas exercise selection can be flexible. Third, age as well as molecular signatures prior to and in response to training influence inter-individual response heterogeneity. Finally, while inter-individual variability in observed hypertrophic responses is considerable, delineating true inter-individual variability from random variation remains challenging. Hence, study design considerations that can be thoughtfully applied to enhance rigor include repeat validation trials, unilateral within-subject designs, minimum clinically important difference thresholds, and multivariate composite responder classifications. This paper aims to summarize conference highlights while also providing meaningful implications for both researchers and practitioners and advancing current thinking on heterogeneity in the resistance training response.

Journal of Applied Physiology
University of Copenhagen (DK), Pennsylvania State University (US), Florida Institute for Human and Machine Cognition (US), University of Wisconsin–Madison (US), Ritsumeikan University (JP), University of Nottingham (GB), Innsbruck Medical University (AT), Lehman College (US), Universidade Federal de São Carlos (BR), Universität Innsbruck (AT), Ghent University Hospital (BE), University of Alabama at Birmingham (US), Central Finland Health Care District (FI), Auburn University (US), University of Jyväskylä (FI), McMaster University (CA)
U.S. Department of Defense, Auburn University, Peanut Institute, Edward Via College of Osteopathic Medicine, Academy of Finland, Suomen Kulttuurirahasto, Lundbeckfonden, Päivikki ja Sakari Sohlbergin Säätiö, Business Finland, National Institutes of Health, National Institute of Arthritis and Musculoskeletal and Skin Diseases, Professional Staff Congress and City University of New York, Renaissance Fund
Openalex Percentile: Top 3%
Cardiovascular and exercise physiology
DOIOpen Access PDFOpenAlex
AI Navigator

Ask Laika to Summarize, Analyze, and Connect papers live on the map.

Summarize Papers & Methodologies

Extract key findings, datasets, and comparative methods across publications.

Benchmark Rankings & Visual Analytics

Rank top research institutions, authors, funders, topics, and journals by Field-Weighted Citation Impact (FWCI) and paper volume with instant charts.

Connect Distant Disciplines

Bridge topological clusters on the map to find hidden collaborative intersections.