Differential Modulation of Hypertrophic and Atrophic Regulatory Factors Following Eight Weeks of High-Intensity Interval and Resistance Training in Athletic vs. Non-Athletic Young Women

چکیده مقاله

introduction: Follistatin, myostatin, and irisin are key proteins involved in the regulation of muscle hypertrophy and atrophy. Physical inactivity and sarcopenia can disrupt the molecular mechanisms and activities of these proteins. Therefore, the present study aimed to investigate the effects of eight weeks of high-intensity interval and resistance training on serum levels of myostatin, follistatin, and irisin in young athletic and non-athletic women. Methods: In this study, forty-eight young women aged 18 to 25 years, both athletes and non-athletes, from Tabas city were purposefully selected and randomly assigned to four groups of 12 participants each (athletic and non-athletic groups performing HIIT and resistance training). The training programs were conducted for eight weeks, three sessions per week. The HIIT protocol consisted of three sets of the RAST protocol (six 35-meter sprints at maximal speed with 10-second rest intervals between runs), progressively increased up to eight sets by the eighth week. The resistance training group performed circuit exercises including eight upper- and lower-body movements, three times per week, at an intensity of 65–85% of 1RM. Data were analyzed using one-way ANOVA. Results: The results showed that in all four groups, the post-test mean levels of serum myostatin, follistatin, and irisin improved compared to the pre-test, with athletic participants showing better performance than non-athletic ones (P=0.001). Moreover, the one-way ANOVA analysis indicated no significant differences among the four groups in serum myostatin and follistatin levels (P>0.05), whereas a significant difference was observed among the groups in serum irisin levels (P<0.05). Conclusion: Based on the findings, it can be concluded that high-intensity interval and resistance training effectively improved the biological function of skeletal muscle. Therefore, these training methods can be recommended for use by