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.

在维持体力活动的同时缺席有人监督的集体锻炼可能是成年人锻炼习惯的常见模式。本研究的目的是确定绝经后早期骨质减少女性在 3 个月的停止训练期后停止训练对肌肉骨骼结果的影响。由于 COVID-19 大流行，我们在 13 个月的随访评估后立即终止了为期 18 个月的随机对照 ACTLIFE 运动干预。这使得运动组（EG： n  = 27）每周进行三次的高强度有氧运动和阻力组运动课程以及注意力对照组（CG：n = 27）每周进行一次的温和运动计划突然停止。 = 27); 但在 3 个月的封锁期内，两组人都被允许进行个人户外活动。研究终点是去脂体重 (LBM)、腰椎 (LS) 骨矿物质密度 (BMD)、最大髋部/腿部伸展力量和力量。 与 CG 相比，停止训练引起的 LBM、臀部/腿部力量和力量（但不是 BMD-LS）的降低明显更大（p  < 0.001 至p = 0.044）。LBM ( p  = 0.157) 和 BMD-LS ( p = 0.065)的显着运动效果（即运动 13 个月后出现的 EG 和 CG 之间的差异）在停止训练 3 个月后消失 ，但力量方面则不然（p  < 0.001） ）和功效（p  < 0.001）。值得注意的是，在封锁期间，两组自我报告的个人户外活动和锻炼量都增加了约 40%。三个月缺席受监督的团体锻炼方案会对肌肉骨骼参数产生相当大的训练效果。因此，成人的锻炼计划应该是连续的而不是间歇性的。

试验注册号：ClinicalTrials.gov：NCT04420806，2020 年 5 月 6 日。