Long-term effects of multicomponent training on body composition and physical fitness in breast cancer survivors: a controlled study.

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. This experimental and controlled study included 19 breast cancer survivors with 64.0 ± 8.6 years, to evaluate long-term effects (32 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. After 32 weeks, the experimental group showed significant reductions in body weight (Δ = - 1.67 kg; BF = 15.15; Cohen's d = 0.19) and body fat percentage (Δ = - 3.99%; BF = 34.87; Cohen's d = 0.73), while no relevant changes were observed in the control group. Improvements were also observed in upper limb strength (Δ =  + 14.14 reps; BF = 1022.02; Cohen's d = 3.45), strength in the surgically affected arm (Δ =  + 13.57 reps; BF = 121.39; Cohen's d = 2.37), lower limb strength (Δ =  + 7.86 reps; BF = 206.55; Cohen's d = 2.24), and aerobic fitness (Δ =  + 97.57 reps; BF = 157.28; Cohen's d = 0.10). Flexibility and dynamic balance also improved, with moderate to large effect sizes. 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.