Research into resistance training response heterogeneity: a summary of the 2025 conference at the University of Jyväskylä
Year: 2026
Type: article
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 multidimensional 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 before and in response to training influence interindividual response heterogeneity. Finally, while interindividual 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.
Source: Journal of Applied Physiology
Institutions: Auburn University, Florida Institute for Human and Machine Cognition, University of Alabama at Birmingham, University of Wisconsin–Madison, University of Copenhagen, Ghent University, Ritsumeikan University, University of Nottingham, McMaster University, Lehman College, Pennsylvania State University, Innsbruck Medical University, Universität Innsbruck, University of Jyväskylä, Universidade Federal de São Carlos
Language: English
Subfield: Orthopedics and Sports Medicine
Field: Medicine
Domain: Health Sciences
Open Access status: hybrid
Funders: U.S. Department of Defense, Auburn University, Peanut Institute, Edward Via College of Osteopathic Medicine, Academy of Finland, Business Finland, National Institutes of Health, National Institute on Aging, National Institute of Arthritis and Musculoskeletal and Skin Diseases, Professional Staff Congress and City University of New York, Renaissance Fund
Awards: G1190825394, Towards personalized exercise: Identifying the determinants of individual variation in resistance training, detraining, and retraining (TraDeRe), G2257206782, G3197595153, Multidimensional predictive modeling to understand mechanisms of exercise response heterogeneity in older adults, Maximizing Mechanisms of Muscle Hypertrophy to Combat Sarcopenia in Older Adults, G6903844668, G7241418887, Mechanotransduction and the Regulation of Skeletal Muscle Mass, Investigating causal interactions between physical activity and cardiometabolic disease via polygenic risk scores (GenActive), G9000345443, Identifying the Structural Adaptations that Drive the Mechanically Induced Growth of Skeletal Muscle, Ribosomal control of muscle mass: Transcriptional and epigenetic mechanisms
OpenAlex ID: W7162126350