The effect of circuit training on muscle synthesis’s indices, neurotrophic factors, and physical fitness in elderly women: A randomized controlled trial

Background Regular physical activity can improve muscle synthesis, cognitive function, and physical fitness and consequently delay the side effects of aging. However, the effect of circuit training, which improves multiple components of physical fitness, is still unknown. Therefore, this study aimed to evaluate the effect of 8 weeks of a mixed circuit training on serum levels of muscle synthesis indices, neurotrophic factors, and physical fitness in elderly women. Methods A total of 24 healthy elderly females (age 65 ± 3 years) were recruited and randomly divided into two groups as follows: Mixed Circuit Training (MCT, n = 12) and Control (C, n = 12). Participants in the MCT group performed circuit training (three times a week at an intensity of 40–60% of 1 repetition maximum) for 8 weeks. Participants in the C group did not received any intervention. Serum levels of growth hormone (GH), Insulin-like growth factor-1 (IGF_1), brain derived neurotrophic factor (BDNF), nerve growth factor (NGF), and physical fitness (cardiovascular fitness, muscular endurance, and balance) were measured before and after the eight weeks of intervention. Results Serum levels of GH, IGF-1, BDNF, and, NGF were increased in the MCT group after eight weeks (p ˂0.001). Cardiovascular fitness, muscular endurance, and balance were also improved in the MCT group after eight weeks of intervention (p ˂0.001). Conclusions A mixed circuit training could improve muscle synthesis, neurotrophic factors, and physical fitness in elderly women. To confirm these results, further studies are recommended. Trial registration Retrospectively registered. IRCT20240108060648N1. Registration date: 2024/02/12. URL: https://irct.behdasht.gov.ir/search/result?query=IRCT20240108060648N1