RESISTANCE TRAINING VOLUME IN TRAINED INDIVIDUALS: CAN LARGE INCREASES LEAD TO REDUCED MUSCULAR ADAPTATIONS?

• Grant number: 25/01715-0
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate
• Start date: September 01, 2025
• End date: January 01, 2026
• Field of knowledge: Health Sciences - Physical Education
• Principal Investigator: Cleiton Augusto Libardi
• Grantee: Júlio Benvenutti Bueno de Camargo
• Supervisor: Michael Roberts
• Host Institution: Centro de Ciências Biológicas e da Saúde (CCBS). Universidade Federal de São Carlos (UFSCAR). São Carlos , SP, Brazil
• Institution abroad: Auburn University, United States
• Associated to the scholarship: 24/14207-0 - Resistance training volume in trained individuals: can larger increases promote smaller muscular adaptations?, BP.DR

Abstract

In order for skeletal muscle hypertrophy to occur continuously throughout a resistance training (RT) program, it is recommended that its prescription consider the principle of progressive overload. One to ensure progressive overload through the manipulation of training variables such as volume (number of sets per week/muscle group). Although the optimal magnitude of volume progression to maximize muscle hypertrophy has yet to be determined, it has been suggested that large and abrupt progressions may impair the skeletal muscle hypertrophy induced by training as a result of an increased proteolytic response. However, this hypothesis has yet to be confirmed. Therefore, the aims of the present study will be: (1) to verify whether increases of 120% in relation to the volume previously performed (VOL120) can attenuate both fiber and whole-muscle hypertrophic response compared to increases of 20% (VOL20); (2) to acutely and chronically compare the levels of muscle proteolysis biomarkers (ubiquitin/proteasome pathways and calpains) between the experimental protocols. In an within-subject, single-blind design, 30 subjects (15 female and 15 male) will have their legs randomized to one of the experimental conditions (VOL120 vs. VOL20). The cross-sectional area of the fibers (immunohistochemistry) and of the vastus lateralis muscle (ultrasound) will be assessed. In addition, the expression of proteins involved in the ubiquitin/proteasome proteolytic pathways (MuRF-1, Atrogin-1, FOXO1, FOXO3, 20S proteasome) and calpains (isoforms 1, 2 and 3) will be analyzed through the Western Blotting technique. As a result, it is expected that a progression of 120% in RT-volume will promote attenuated muscle hypertrophy compared to a progression of 20% in weekly volume. In this sense, it is also expected that the 120% volume progression will promote a greater acute and chronic response of proteolytic biomarkers compared to a progression of lower magnitude.