Effects of Resistance Training and Protein Supplementation in Breast Cancer Survivors

Purpose: This study aimed to evaluate 12 wk of resistance training (RT; n = 16) and protein supplementation (RT + protein; n = 17) on muscular strength, body composition, and blood biomarkers of muscle (insulin-like growth factor 1 [IGF-1]), fat (adiponectin), and inflammation (human C-reactive protein [CRP]) in breast cancer survivors (BCS). Methods: Thirty-three BCS (59 +/- 8 yr) were measured pre- and posttraining for one-repetition maximum (1-RM) muscular strength (chest press and leg extension), body composition (lean mass [LM] and fat mass [FM]) via dual-energy x-ray absorptiometry, and serum concentrations of IGF-1, adiponectin, and CRP. RT consisted of 2 d.wk(-1) using 10 exercises for two sets of 10-12 repetitions and a third set to failure at similar to 65%-85% of 1-RM. RT + protein consumed 20 g of protein twice a day. ANOVA was used for analyses. Significance was set at P <= 0.05. Results: Average RT intensity was 65%-81% of 1-RM and was not different between RT and RT + protein. There were no group-time interactions for strength, LM, FM, and biomarkers. Both groups significantly increased upper (+31 +/- 18 kg) and lower (+/- 19 +/- 12 kg) body strength, LM(+0.9 +/- 1.0 kg) and decreased FM (-0.5 +/- 1.2 kg), and percent body fat (-1.0% +/- 1.2%). Serum levels of IGF-1 significantly increased from baseline to 12 wk in both RT (102 +/- 34 to 115 +/- 33 ng.mL(-1)) and RT + protein (110 +/- 40 to 119 +/- 37 ng.mL(-1)); adiponectin and CRP did not change. Conclusions: Twelve weeks of RT at 65%-81% of 1-RM, 2 d.wk(-1) in BCS, was well tolerated and significantly improved strength, body composition, and IGF-1. Supplemental protein (40 g.d(-1)) did not induce a change in any variable. However, on the basis of food logs, reductions in total calories and dietary protein intake from whole foods resulted in only a net protein increase of 17 g.d(-1) for RT + protein, which may have influenced the results.