Long-term exercise adherence and body composition after completion of an intense resistance training regimen during and after treatment for breast cancer

Abstract Purpose High-intensity resistance training regimen utilizing compound movements is safe and effective in improving body composition, strength, balance, mobility, and quality of life after 3 months. However, the long-term impact of this regimen is unknown. This study assessed these factors one year after completion of the program. Methods Participants of the EXERT-BC protocol returned at one year for assessment of body composition, phase angle, functional mobility, balance, resting metabolic rate, quality of life, activity levels, and strength, analyzed as continuous variables. Pairwise comparisons were assessed via the paired t test. Results In total, 33 participants returned in one year for reevaluation, with 7 alive, 6 lost to follow-up and 1 unable to follow up due to unrelated hospitalization (Figure 1). Median age at reevaluation was 57.75 years, with 15 patients (45.5%) over 60 years (range, 28-76 years). Out of the 33 women, 16 (48.5%) described continued weekly exercise, while 14 of them (42.4%) were on a structured resistance training program. Five women (15.2%) experienced musculoskeletal injuries between completion of EXERT-BC and one year follow-up inhibiting their ability to exercise. Three women who were not exercising (9%) experienced orthopedic injuries requiring medical intervention. Four women (12.1%) stopped exercise due to due to surgeries related to their breast cancer. Of the nine women on the initial EXERT-BC study with a history of exercise, all continued exercise at one year. Generally, metabolic and anthropomorphic factors that were improved on initial evaluation were no longer significant at one year. No significant change was seen in weight at any time point. At completion of the exercise regimen significant reductions were seen in percent body fat, total body fat, excess fat, and significant increases in muscle mass amount and percent, resting metabolic rate, and whole body phase angle, these changes were no longer significant at 1-year. Godin measurement of activity levels and quality of life via EQ5D were no longer significantly changed. Strength, mobility, and balance metrics, however, remained significant one year after the exercise intervention, including grip strength, balance, functional mobility. Further analysis in the 17 individuals no longer exercising at one year and the 16 individuals still exercising revealed similar findings. Conclusion After a 3-month dose-escalated resistance training regimen exercise compliance is poor at one year. The anthropomorphic benefits of the regimen regress by one year, however, the improvements in strength, balance, and mobility persist.