Effects of Intensive Periodized Training with Multi-Strain Probiotic Supplements on Training Adaptation and Exercise Performance in Amateur Runners

OBJECTIVE: This randomized, double-blind, placebo-controlled study investigated whether intensive periodized training combined with multi-strain probiotics affects training adaptation and exercise performance in amateur runners. METHODS: = 15) during a four-week, intensive periodized training program. Two participants withdrew from the PG. Before and after the intervention, comprehensive laboratory, physical, and psychological assessments were conducted to evaluate training adaptation and exercise performance. RESULTS: , accompanied by increased cortisol levels and a reduced testosterone-to-cortisol ratio. Probiotic supplementation alongside training attenuated biomarkers of exercise-induced muscle damage and endocrine disturbance, including Alanine aminotransferase levels, reduced athlete burnout scores, and modulated the fecal Firmicutes/Bacteroidetes ratio. Significant group × time interactions were observed for several key bacterial taxa. CONCLUSION: Intensive period training effectively enhances exercise performance and body composition. Probiotic supplementation might provide additional benefits related to training adaptation, gut microbiota modulation, and athlete burnout attenuation.