12 weeks of resistance training with progressive intensity improves the diagnostic parameters of sarcopenia in individuals of advanced age.

OBJECTIVE: The objective of this study was to evaluate the effects of 12 weeks of resistance training (RT) with progressive intensity on factors associated with sarcopenia in older individuals. METHODS: A cross-sectional study was conducted with 74 participants (64.27 ± 7.06-y-old) who were divided into a control group (n = 37) and an intervention group (n = 37). The intervention group underwent 12 weeks of RT three times a week, with an initial training of 60% and final training of 85% of one-repetition maximum (1RM). Both groups were evaluated before and after the 12-week training period to assess improvements in strength and physical performance. RESULTS: The intervention group showed an increase in physical performance, as evidenced by a reduction in the time to perform the Timed Up and Go (TUG) test (p < 0.01) and the Five Times Sit to Stand Test (p < 0.01). Furthermore, the RT proved to be efficient for increasing hand grip and overall muscular strength, as confirmed through the 1RM test. However, the muscle mass index (MMI) and walking speed did not show any significant alterations in both groups. CONCLUSIONS: In conclusion, 12 weeks of RT with progressive intensity has a positive effect on the diagnostic parameters of sarcopenia, leading to improvements in physical performance and muscular strength while maintaining the MMI.

Influence of Alpha-Actinin-3 R577X Polymorphism on Muscle Damage and the Inflammatory Response after an Acute Strength Training Session.

The objective of this study was to verify the influence of the ACTN3 R577X polymorphism on muscle damage and the inflammatory response after an acute strength training (ST) session. Twenty-seven healthy male individuals (age: 25 ± 4.3 years) participated in the study, including 18 RR/RX and 9 XX individuals. The participants were divided into two groups (RR/RX and XX groups) and subjected to an acute ST session, which consisted of a series of leg press, leg extension machine, and seated leg curl machine. The volunteers were instructed to perform the greatest volume of work until concentric muscle failure. Each volunteer's performance was analyzed as the load and total volume of training, and the blood concentrations of C-C motif chemokine ligand 2 (CCL2), interleukin-8 (IL-8), creatine kinase (CK), lactate dehydrogenase (LDH), myoglobin, testosterone, and cortisol were measured before the ST session and 30 min and 24 h postsession. The ACTN3 R577X polymorphism effect was observed, with increased concentrations of CCL2 (p < 0.01), IL-8 (p < 0.01), and LDH (p < 0.001) in XX individuals. There was an increase in the concentration of CK in the RR/RX group compared to XX at 24 h after training (p > 0.01). The testosterone/cortisol ratio increased more markedly in the XX group (p < 0.001). Regarding performance, the RR/RX group presented higher load and total volume values in the training exercises when compared to the XX group (p < 0.05). However, the XX group presented higher values of delayed onset muscle soreness (DOMS) than the RR/RX group (p < 0.05). The influence of ACTN3 R577X polymorphism on muscle damage and the inflammatory response was observed after an acute ST session, indicating that the RR/RX genotype shows more muscle damage and a catabolic profile due to a better performance in this activity, while the XX genotype shows more DOMS.