Long-term effects of multicomponent training in the body composition and physical fitness of breast cancer survivors: a controlled and experimental study with clustering analysis

Introduction: Multicomponent training is suggested as an efficient way to address the side effects of long-term treatment in breast cancer survivors and reduce the age-related relapse risk in these patients. This study aimed to evaluate the impact of a multicomponent training intervention on breast cancer survivors' physical fitness and body composition. Methods: This experimental and controlled study included 19 breast cancer survivors with 64.0 ± 8.6 years, to evaluate long-term effects (36 weeks) of multicomponent training on body composition [body weight (kg), body mass index, body fat (%), lean mass (kg), body water (%), basal metabolism (Kcal) and visceral fat (index)] and physical fitness [Upper limb strength (repetitions), lower limb strength (repetitions), upper limb flexibility (cm), lower limb flexibility (cm), dynamic balance (seconds), and aerobic fitness (repetitions)]. Bayesian statistical tests were employed to analyze the reduced dataset size, considering a Bayes factor ≥ 10 as the cutoff for significant differences. Hierarchical clustering identified participant improvements using Manhattan distance, and clusters were ranked by responsiveness. Results: The experimental improved body weight, body fat percentage, and physical fitness after the intervention, while no changes were observed in the control group. Cluster analysis showed that higher responders varied from 28% to 86% across variables, while others showed lower, but still positive, responses. Discussion and Conclusion: The multicomponent physical exercise program effectively improved all physical fitness variables but was limited in body composition, exposing improvements only in body weight and % body fat. The intervention did not cause any side effects or injury to the participants.