Researchers from the Universities of Hildesheim, Bonn, and Freiburg have now uncovered how human skeletal muscle responds to resistance exercise at the molecular level. Their findings provide new insights that could help optimize training programs for athletes, improve rehabilitation strategies, and counteract age-related muscle loss. Resistance training is essential for maintaining healthy skeletal muscle throughout life. The World Health Organization now recommends moderate muscle-strengthening activities at least twice a week, even for older adults, to help prevent the loss of muscle strength. The new study is published in the latest issue of Nature Communications .
Regular physical activity is crucial for healthy ageing. However, endurance exercise alone is not sufficient to maintain muscle mass. High-intensity resistance exercise is required to increase or preserve skeletal muscle. Such exercise also places considerable mechanical stress on muscle fibers, causing microscopic damage to the contractile machinery responsible for force generation. Until now, little has been known about how skeletal muscle repairs this damage and adapts to repeated resistance training. An interdisciplinary team of exercise physiologists, cell biologists, and proteomics experts from the Universities of Hildesheim, Bonn, and Freiburg has now provided important new insights into these underlying mechanisms.
Resistance Training Activates the Muscle Repair Machinery
To investigate these processes, the researchers collected muscle biopsies from healthy volunteers before and after a bout of high-intensity resistance exercise. They also examined how a prolonged period of reduced training and complete cessation of resistance exercise affected these molecular adaptations. Using state-of-the-art proteomics approaches, the team identified dynamic changes within the contractile apparatus of skeletal muscle.
The researchers found that resistance training activates a specialized repair system that recognizes damaged muscle components and targets them for removal. At the same time, this repair machinery promotes the synthesis of new contractile proteins, replacing those that have been damaged. This coordinated process preserves and reinforces the muscle's contractile apparatus. The study identifies previously unknown components of this muscle repair network and reveals how they are regulated in response to resistance training.
Interdisciplinary Collaboration Enables New Discoveries
"Our analytical approaches allowed us to identify proteins that are recruited to the contractile apparatus after resistance exercise, where they perform essential protective and repair functions," explains Professor Pitter Huesgen, a proteomics expert at the University of Freiburg.
The function of these proteins was subsequently investigated in the laboratory of Professor Jörg Höhfeld at the University of Bonn´s Institute for Cell Biology. "Using cultured muscle cells, we demonstrated that these repair proteins first recognize damaged muscle structures and then remove them through a cellular degradation pathway known as autophagy. This clears the way for muscle repair and adaptation to resistance training," says Professor Höhfeld, who is also a member of the “Life and Health” Transdiciplinary Research Area´s Steering Committee at the University of Bonn.
Implications for Training and Rehabilitation
Professor Sebastian Gehlert and his team at the University of Hildesheim collected the human muscle biopsies and performed the initial analyses of exercise-induced damage to the contractile apparatus.
"Our findings reveal how training intensity and training history influence both muscle damage and the activation of the repair machinery," says Professor Gehlert. "This knowledge will help us optimize the sequencing of training sessions for athletes as well as rehabilitation programs for patients in clinical settings."
Professor Gehlert is already incorporating these findings into the education of exercise scientists and into evidence-based training strategies for elite athletes at Germany's Olympic Training Centers, as well as for members of the police and armed forces.
Funding and Participating Institutions
The study was conducted through a collaboration between researchers at the Universities of Hildesheim, Bonn, and Freiburg, the German Sport University Cologne, and the University of Duisburg-Essen. The work was supported by the German Research Foundation (DFG) and the German Space Agency at the German Aerospace Center (DLR).
Nature Communications
Fractionated proteomics identifies a protein network mitigating resistance exercise-induced damage in human skeletal muscle
28-Jul-2026