Effects of Resistance Training and Protein Supplementation in Breast Cancer SurvivorsMADZIMA, TAKUDZWA A.1; ORMSBEE, MICHAEL J.2,3,4; SCHLEICHER, ERICA A.2; MOFFATT, ROBERT J.2; PANTON, LYNN B.2,3,5
Medicine & Science in Sports & Exercise: July 2017 – Volume 49 – Issue 7 – p 1283–۱۲۹۲
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 ± ۸ 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−۱ using 10 exercises for two sets of 10–۱۲ repetitions and a third set to failure at ~65%–۸۵% of 1-RM. RT + protein consumed 20 g of protein twice a day. ANOVA was used for analyses. Significance was set at P ≤ ۰٫۰۵٫
Results: Average RT intensity was 65%–۸۱% 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 ± ۱۸ kg) and lower (+19 ± ۱۲ kg) body strength, LM (+0.9 ± ۱٫۰ kg) and decreased FM (−۰٫۵ ± ۱٫۲ kg), and percent body fat (−۱٫۰% ± ۱٫۲%). Serum levels of IGF-1 significantly increased from baseline to 12 wk in both RT (102 ± ۳۴ to 115 ± ۳۳ ng·mL−۱) and RT + protein (110 ± ۴۰ to 119 ± ۳۷ ng·mL−۱); adiponectin and CRP did not change.
Conclusions: Twelve weeks of RT at 65%–۸۱% of 1-RM, 2 d·wk−۱ in BCS, was well tolerated and significantly improved strength, body composition, and IGF-1. Supplemental protein (40 g·d−۱) 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−۱ for RT + protein, which may have influenced the results.