Detraining Effects on Musculoskeletal Parameters in Early Postmenopausal Osteopenic Women: 3-Month Follow-Up of the Randomized Controlled ACTLIFE Study

Abstract

Periods of absence from supervised group exercise while maintaining physical activity might be a frequent pattern in adults' exercise habits. The aim of the present study was to determine detraining effects on musculoskeletal outcomes after a 3-month detraining period in early post-menopausal, osteopenic women. Due to the COVID-19 pandemic, we terminated the 18-month randomized controlled ACTLIFE exercise intervention immediately after the 13-month follow-up assessment. This put an abrupt stop to the high-intensity aerobic and resistance group exercise sessions undertaken three times per week by the exercise group (EG: n = 27) and the gentle exercise program performed once per week for the attention control group (CG: n = 27); but both groups were permitted to conduct individual outdoor activity for the 3-month lock-down period. Study endpoints were lean body mass (LBM), bone mineral density (BMD) at the lumbar spine (LS), maximum hip-/leg extension strength and power. Detraining-induced reductions of LBM, hip/leg strength and power (but not BMD-LS) were significantly greater (p < 0.001 to p = 0.044) compared with the CG. Significant exercise effects, i.e. differences between EG and CG, present after 13 months of exercise, were lost after 3 months of detraining for LBM (p = 0.157) and BMD-LS (p = 0.065), but not for strength (p < 0.001) and power (p < 0.001). Of note, self-reported individual outdoor activities and exercise increased by about 40% in both groups during the lock-down period. Three months' absence from a supervised group exercise protocol resulted in considerable detraining effects for musculoskeletal parameters. Thus, exercise programs for adults should be continuous rather than intermittent.Trial registration number: ClinicalTrials.gov: NCT04420806, 06.05.2020.

Keywords: Bone mineral density; Detraining; High-intensity exercise; Lean body mass; Strength and power.

Fig. 1

Participant flow through the ACTLIFE study

Fig. 2

Mean values and 95% CI for changes of Lean Body Mass (LBM) after training and detraining based on the intention to treat analysis (n = 27 in the EG and CG). # significant difference in changes from 13-month (end of intervention) to 3-month FU (16 month) in the EG vs. CG

Fig. 3

Mean values and 95% CI for changes of BMD at the lumbar spine after training and detraining based on the intention to treat analysis (n = 27 in the EG and CG)

Fig. 4

Mean values and 95% CI for changes of hip-leg extensor strength after training and detraining based on the intention to treat analysis (n = 27 in the EG and CG). # significant difference in changes from 13-month (end of intervention) to 3-month FU (16 month) in the EG vs. CG. ǂ significant different changes from baseline to 16 month (i.e. “overall effects”)

Fig. 5

Mean values and 95% CI for changes of leg power after training and detraining based on the intention to treat analysis (n = 27 in the EG and CG). # significant difference in changes from 13-month (end of intervention) to 3-month FU (16 month) in the EG vs. CG. ǂ significant different changes from baseline to 16 month (i.e. “overall effects”)