Scientific Programme
Sports and Exercise Medicine and Health
IS-MH10 - Muscle Fiber Phenotype as a Unifying Framework for Understanding Sports Performance, Health, and Disease
Date: 08.07.2026, Time: 16:45 - 18:00, Session Room: SG 1138 (EPFL)
Description
Health promotion, disease prevention, and sports performance are often treated as distinct disciplines, yet the biology of muscle fibers offers a unifying framework that connects them. Recent advances in single-cell profiling now allow unprecedented resolution in defining muscle fiber phenotype, revealing mechanisms that simultaneously shape athletic performance and metabolic health. This symposium leverages these developments to illuminate how differences in muscle fiber composition influence performance capacity, adaptability, fatigue resistance, while also contributing to susceptibility to obesity, diabetes, and sarcopenia. By integrating perspectives from advanced experimental methodologies, sports science, physiology, and medical research, the session exemplifies the interdisciplinary mission of ECSS and highlights how fiber-type biology can guide personalized training, targeted recovery strategies, and evidence-based approaches to maintaining or improve muscle health across diverse populations. The symposium is crafted for sports scientists, exercise physiologists, academic researchers and clinicians, with the goal of fostering meaningful cross-disciplinary dialogue and advancing innovative strategies to optimize muscle metabolism and function in sports, health, and disease.
Chair(s)
Christos Katsanos
Arizona State University, School of Life Sciences
United States
Speaker A
Marta Murgia
Universita' degli studi di Padova, Dipartimento di Scienze Biomediche
Italy
Read CVECSS Lausanne 2026: IS-MH10 [36325]
Spatial Proteomics of Single Muscle Fibers: Mapping Subcellular Diversity in Health and Disease
Single muscle fiber proteomics has provided detailed insights into skeletal muscle physiology and pathology, demonstrating that slow and fast muscle fibers exhibit distinct proteome profiles and undergo different plasticity events during aging, exercise, and disuse. While this research continues to yield valuable information, recent advances in proteomics technology are opening new avenues for investigation. Deep visual proteomics has emerged as a powerful approach for addressing spatial features and cell heterogeneity across different tissues, with recent applications leading to the identification of novel therapeutic targets. Building on these technological developments, we are now applying this paradigm to single muscle fiber analysis. Our current research employs recently developed mass spectrometry approaches to investigate single muscle fibers at the subcellular level, adding a spatial dimension to our understanding of muscle fiber proteome diversity. This approach allows us to map the distribution of proteins within individual fibers, revealing how molecular machinery is organized in different cellular compartments and how this organization changes under various physiological and pathological conditions. This spatial proteomics approach represents the next step in understanding muscle fiber complexity and may reveal new molecular mechanisms underlying muscle function, adaptation, and disease.
Speaker B
Phillip Bellinger
Griffith University, School of Allied Health Sciences
Australia
Read CVECSS Lausanne 2026: IS-MH10 [18913]
The application of muscle typology in elite sport: Individualized training, pacing and talent identification
Muscle fibres have traditionally been classified by analyses of their myosin heavy chain isoforms revealing three major fibre types that can be identified as type I, IIA and IIX fibres (Schiaffino et al. 2011). These skeletal muscle fibre types show a large diversity in their physiological and mechanical characteristics. Classical studies from the 1970’s and 1980’s (Gollnick et al. 1972; Costill et al. 1976; Gerard et al. 1986; Houston et al. 1981) showed that muscle typology differentiated between athletes specializing in different sport disciplines, as well as the competitive level of athletes within these disciplines. Variation in muscle typology may be important for specializing in different sports and for individualizing training and recovery cycles. Despite the high relevance of muscle typology in elite sport, it is currently not widely used to guide sport science practice by coaches and sport science practitioners. This is mostly due to the invasiveness of the muscle biopsy technique, which is typically met with resistance from athletes. With the advent of a newly developed technique to non-invasively estimate muscle typology, through the measurement of muscle carnosine by proton magnetic resonance spectroscopy (Baguet et al. 2011), this limitation can be addressed. Identifying the muscle typology of athletes using this non-invasive technology can be implemented by coaches and practitioners to guide training content for prescription (i.e., individualized training), determine the suitability of an athlete to a particular sport or discipline (i.e., talent identification) and to optimize tactical racing strategies (i.e., pacing). Indeed, recent research has demonstrated the application of muscle typology to pacing and performance in middle distance swimming (Mallett et al. 2020) and running (Bellinger et al. 2021a and 2021b), as well as talent identification and transfer by benchmarking world-class and elite athletes across the sports of swimming (Bellinger et al. 2022) track and field (Vandecauter et al. 2025) and cycling (Lievens and Bellinger et al. 2021). Furthermore, recent research has established training program related considerations that are moderated by muscle typology such as the training intensity distribution (Bourgois et al. 2020), fatigue and recovery in acute (Lievens et al. 2020) and chronic (Bellinger et al. 2020) training scenarios as well as in resistance training (Van Vossel et al. 2023). In this presentation, Dr Bellinger will present both published and unpublished research demonstrating the application of muscle typology across key aspects of elite sport, such as talent identification, pacing, fatigue and recovery in acute and chronic training settings and injury profiling risk, using practical examples from track-and-field, cycling, rowing and team sports. The presentation would appeal to applied sport science researchers as well as fundamental scientists.
Speaker C
Christos Katsanos
Arizona State University, School of Life Sciences
United States
Read CVECSS Lausanne 2026: IS-MH10 [36020]
Muscle Fiber Types as Drivers of Obesity-Related Metabolic and Functional Dysfunction
Obesity is characterized by profound disturbances in skeletal muscle metabolism and function, and accumulating evidence suggests that muscle fiber phenotype is a central contributor to these abnormalities. Human studies consistently demonstrate a reduced proportion of oxidative type I fibers and a shift toward more glycolytic type IIx fibers in individuals with obesity, a pattern linked to impaired glucose disposal, greater intramuscular lipid accumulation, reduced mitochondrial content, diminished protein turnover, lower physical activity, and poorer muscle quality. Although causal relationships in humans remain currently under intense investigation, both environmental factors, such as inactivity, hypercaloric diets, and genetic influences appear to drive this slow-to-fast transition, as supported by rodent models, thereby reinforcing the connection between altered muscle fiber phenotype and obesity-related dysfunction. Despite decades of investigation, much of what is known stems from methodologies that cannot resolve hybrid fibers. These fibers are a mixture of pure fiber types likely representing transitional or adaptive states in muscle fiber phenotype. We will present novel evidence from humans indicating that the proportion of hybrid fibers increases in those with obesity and that these hybrid fibers may account for the striking heterogeneity in metabolic flexibility, contractile performance, and functional capacity among individuals with obesity. This symposium segment will synthesize insights from human muscle physiology, molecular profiling, and emerging single-fiber proteomics to illustrate how fiber-type distribution shapes metabolic and functional impairments in obesity. Emphasis will be placed on mechanistic pathways through which fiber phenotype influences lipid handling, mitochondrial function, and protein turnover, and how these pathways may be targeted through exercise, nutrition, and pharmacotherapy. A deeper understanding of how pure and hybrid muscle fiber types contribute to obesity-related dysfunction is essential for developing interventions that sustain muscle health, and improve metabolic regulation, and functional capacity in individuals living with obesity.