Impact of Short-Term Creatine Supplementation on Muscular Performance among Breast Cancer Survivors.

Breast cancer (BC) is one of the most common cancers in the United States. Advances in detection and treatment have resulted in an increased survival rate, meaning an increasing population experiencing declines in muscle mass and strength. Creatine supplementation has consistently demonstrated improvements in strength and muscle performance in older adults, though these findings have not been extended to cancer populations. PURPOSE: The purpose of this study was to investigate the effects of short-term creatine supplementation on muscular performance in BC survivors. METHODS: Using a double-blind, placebo-controlled, randomized design, 19 female BC survivors (mean ± SD age = 57.63 ± 10.77 years) were assigned to creatine (SUPP) (n = 9) or dextrose placebo (PLA) (n = 10) groups. The participants completed two familiarization sessions, then two test sessions, each separated by 7 days, where the participants supplemented with 5 g of SUPP or PLA 4 times/day between sessions. The testing sessions included sit-to-stand power, isometric/isokinetic peak torque, and upper/lower body strength via 10 repetition maximum (10RM) tests. The interaction between supplement (SUPP vs. PLA) and time (Pre vs. Post) was examined using a group × time ANOVA and effect sizes. RESULTS: No significant effects were observed for sit-to-stand power (p = 0.471; ηp2 = 0.031), peak torque at 60°/second (p = 0.533; ηp2 = 0.023), peak torque at 120°/second (p = 0.944; ηp2 < 0.001), isometric peak torque (p = 0.905; ηp2 < 0.001), 10RM chest press (p = 0.407; ηp2 = 0.041), and 10RM leg extension (p = 0.932; ηp2 < 0.001). However, a large effect size for time occurred for the 10RM chest press (ηp2 = 0.531) and leg extension (ηp2 = 0.422). CONCLUSION: Seven days of creatine supplementation does not influence muscular performance among BC survivors.

Considerations for designing trials targeting muscle dysfunction in exercise oncology.

Individuals diagnosed with cancer commonly experience a significant decline in muscle mass and physical function collectively referred to as cancer related muscle dysfunction. This is concerning because impairments in functional capacity are associated with an increased risk for the development of disability and subsequent mortality. Notably, exercise offers a potential intervention to combat cancer related muscle dysfunction. Despite this, research is limited on the efficacy of exercise when implemented in such a population. Thus, the purpose of this mini review is to offer critical considerations for researchers seeking to design studies pertaining to cancer related muscle dysfunction. Namely, 1) defining the condition of interest, 2) determining the most appropriate outcome and methods of assessment, 3) establishing the best timepoint (along the cancer continuum) to intervene, and 4) understanding how exercise prescription can be configured to optimize outcomes.