Effect of resistance training with different frequencies and subsequent detraining on muscle mass and appendicular lean soft tissue, IGF-1, and testosterone in older women

Abstract

Objective: To analyse the effect of resistance training (RT) frequency on muscle mass, appendicular lean soft tissue, insulin-like growth factor 1 (IGF-1), testosterone, and their changes with detraining in older women. Methods: Forty-five physically independent older women (≥ 60 years) were randomly assigned to perform RT either two (G2X, n = 21) or three times/week (G3X, n = 24), during 12 weeks (8 exercises, 1 set of 10–15 repetition maximum). Muscle mass and appendicular lean soft tissue, IGF-1, testosterone, and dietary intake were measured at pre-training, post-training, and after detraining (12 weeks). Results: Muscle mass and appendicular lean soft tissue significantly increased post-training (G2X = +5.5% and G3X = +5.8%, P < .0001) with no differences between groups, and gains were retained after detraining (G2X = 100% and G3X = 99%, P < .0001). IGF-1 and dietary intake did not change for the groups during the study. Testosterone did not change post-training but significantly decreased after detraining (G2X = −21% and G3X = −50%, P < .0001). Conclusion: We conclude that lower RT frequency is as effective as higher frequency to improve muscle mass and appendicular lean soft tissue, and to maintain testosterone and IGF-1. Additionally, detraining may reduce testosterone regardless of RT frequency. These results are specifically for community-dwelling older women and may not be generalized to other populations.

Keywords:

• Ageing
• strength
• body composition, training

Acknowledgements

The authors thank the participants for their valuable collaboration in carrying out this study.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This study was partially funded by the National Council for Scientific and Technological Development (CNPq/Brazil), the Coordination for the Improvement of Higher Education Personnel (CAPES/Brazil) and the Ministry of Education (ProExt /MEC/Brazil).