Tabriz University of Medical Sciences Medical Journal of Tabriz University of Medical Sciences 2783-2031 48 1 2026 05 06 The effect of six weeks of resistance and continuous training on muscle agrin protein expression and serum C-terminal agrin fragment (CAF) levels in a female rats model of sarcopenia 66 77 10.34172/mj.026.35108 EN Mohammad Asadi Golzar https://orcid.org/0000-0002-4014-6309 Abdolhamid Habibi https://orcid.org/0000-0002-9593-920X Saeid Shakerian https://orcid.org/0000-0002-0880-9942 Ghotbeddin Zohreh https://orcid.org/0000-0003-2110-6333 Journal Article 10.34172/mj.026.35108 2025 10 06 2025 12 27 Background. Aging is accompanied by a gradual decline in neuromuscular function, often resulting in reduced motor performance and loss of independence. Sarcopenia, one of the biological consequences of aging, is characterized by a decrease in muscle mass and strength, and several factors-including decreased physical activity-contribute to its development. Given the importance of preserving muscle function in the elderly and the limitations of current therapeutic approaches, exercise training-particularly resistance and continuous training-has been considered as an effective non-pharmacological intervention. Therefore, the present study aimed to investigate the effects of six weeks of resistance or continuous training on muscle agrin protein expression and serum C-terminal agrin fragment (CAF) levels in female rats with sarcopenia. Methods. In this experimental study, female rats were randomly divided into four groups: control, sarcopenia, sarcopenia+resistance training, and sarcopenia+continuous training (n=3 per group). The training groups performed six weeks of resistance or continuous exercise. Forty-eight hours after the final training session, fast-twitch extensor digitorum longus (EDL) muscles were harvested to assess agrin protein expression, and blood samples were collected to obtain serum for the measurement of CAF levels. Results. The findings demonstrated that both resistance and continuous training significantly increased agrin protein expression in the fast-twitch EDL muscle (P<0.01) and decreased serum CAF levels (P<0.05). Conclusion. The results suggest that resistance and continuous training exert protective effects on the neuromuscular junction and may play a potential role in delaying the progression of sarcopenia. Practical Implications. The findings of this study can represent an effective step in the field of exercise for elderly and provide valuable insights for preventing the progression of sarcopenia in this population.