The effect of resistance training on muscle strength and physical function in older, postmenopausal breast cancer survivors: a randomized controlled trial

Abstract

Older breast cancer survivors (BCS) report more falls and functional limitations than women with no cancer history. Exercise training could reduce risk factors for future falls and disability. We conducted a randomized, controlled trial in 106 early-stage, postmenopausal BCS who were ≥50years old at diagnosis and post-treatment. Women were randomly assigned to a 1-year resistance + impact exercise program or a stretching placebo program. Endpoints were one repetition maximum bench press and leg press strength, timed five chair stands, 4m usual walk speed, timed stance tests, handgrip strength, self-report physical function, and fatigue. We also examined the influence of age, adjuvant hormone therapy use, and exercise adherence on study outcomes. Women in the resistance + impact training program significantly improved maximal leg (p <0 .02) and bench (p <0 .02) press strength compared to the stretching group. Women who attended 50% or more of prescribed resistance training sessions had significantly better changes in maximal strength measures compared to less adherent women. Resistance + impact exercise is superior to stretching at improving maximal muscle strength and exercise adherence contributes to the degree of improvement. Older BCS can safely engage in resistance exercise that improves lower and upper body strength, thereby reducing a risk factor for falls and future disability. However, the ability of resistance training to shift other indices of fall and disability risk, i.e., balance and function, is unclear. Strategies to promote adherence to resistance training could lead to greater improvements in strength.