Skeletal muscle mass, strength, and physical performance gains are similar between healthy postmenopausal women and postmenopausal breast cancer survivors after 12 weeks of resistance exercise training.

Purpose: Resistance exercise training (RET) effectively increases skeletal muscle mass and strength in healthy postmenopausal women. However, its effects on these parameters in postmenopausal breast cancer survivors are controversial or limited. Therefore, the aim of this study was to compare the effects of a 12-week progressive whole-body RET program on skeletal muscle mass, strength, and physical performance in healthy postmenopausal women versus postmenopausal women who survived breast cancer.

Methods: Thirteen healthy postmenopausal women (HEA, 54 ± 3 years, BMI 26.6 ± 2.7 kg·m², n = 13) and eleven postmenopausal breast cancer survivors (BCS, 52 ± 5 years, BMI 26.8 ± 2.1 kg·m², n = 11) participated in the study. Before and after the RET program, evaluations were performed on quadriceps muscle thickness, one-repetition maximum strength (1RM) for various exercises, grip strength, and physical performance.

Results: Both groups showed significant improvements in quadriceps muscle thickness (time effect, P < 0.001); 1RM strength for leg extension, leg press, chest press, horizontal row, and elbow extension (time effect, all P < 0.001); as well as handgrip strength (time effect, P = 0.035) and physical performance (time effect, all P < 0.001) after the 12-week RET program. There were no significant differences between the groups in response to RET for any of the outcomes measured.

Conclusion: Twelve weeks of RET significantly increases skeletal muscle mass, strength, and physical performance in postmenopausal women. No differences were observed between healthy postmenopausal women and postmenopausal breast cancer survivors. These findings point out that this study's RET promotes skeletal muscle mass, strength, and performance gains regardless of breast cancer. Pre-Print Platform Research Square: https://doi.org/10.21203/rs.3.rs-4145715/v1 ; https://www.researchsquare.com/article/rs-4145715/v1 Clinical trial registration: NCT05690295.