Four published papers look at what happens to strength and muscle size when training stops and starts again. This guide reads their PubMed or PubMed Central abstracts, on 2 November 2026: a 2013 meta-analysis of training cessation, a 2011 trial in which 15 young men took a 3-week break, a 2024 randomised trial with a 10-week break, and a 2022 meta-analysis in older adults. Full texts were not used for the figures, so details beyond the abstracts are not covered. The papers say nothing about particular equipment, and this guide makes no claim about dumbbells or kettlebells. General information, not training advice.
What the largest review found about stopping
The 2013 paper by Bosquet and colleagues in the Scandinavian Journal of Medicine and Science in Sports searched seven databases and included 103 of 284 potential studies. It used training status, sex, age and the duration of cessation as moderators and reported standardised mean differences (SMD) with 95% confidence intervals:
- submaximal strength: SMD minus 0.62 (minus 0.80 to minus 0.45)
- maximal force: SMD minus 0.46 (minus 0.54 to minus 0.37)
- maximal power: SMD minus 0.20 (minus 0.28 to minus 0.13)
The abstract reports a dose-response relationship between the size of the effect and the duration of cessation, a larger effect in people over 65, and a larger effect on maximal force and maximal power in inactive people than in recreational athletes. Its conclusion is that resistance training cessation decreases all components of muscular strength, and that the size of the effect differs with training status, age and cessation duration. The abstract does not give a figure in weeks for when losses begin.
Two trials with breaks of 3 and 10 weeks
A 2011 trial by Ogasawara and colleagues, published in Clinical Physiology and Functional Imaging, divided 15 previously untrained young men into a continuous group, which did high-intensity bench press training for 15 weeks, and an interrupted group, which trained for 6 weeks, stopped for 3 weeks and resumed at week 10. The abstract reports no significant decreases in muscle cross-sectional area or one repetition maximum after the 3-week break, similar gains in muscle size after retraining to those after the initial block, and similar improvements in both groups after the 15-week period. The authors suggest that, compared with continuous training, 3-week detraining does not inhibit muscle adaptations.
A 2024 trial in the Scandinavian Journal of Medicine and Science in Sports randomised 55 healthy untrained participants, aged 32 plus or minus 5 years, to periodic or continuous training; 20 and 22 completed the study in the two groups. The periodic group did 10 weeks of twice-weekly supervised whole-body training, 10 weeks of detraining and a second 10-week block. The continuous group did 10 weeks without training, then 20 weeks of training. Both groups increased leg press and biceps curl 1RM, muscle size at two sites and countermovement jump height, with no differences between them. In the periodic group, those measures decreased during the 10 weeks of detraining. Over the first 5 weeks of retraining, the periodic group’s increases in leg press 1RM and muscle size at both sites were greater than the continuous group’s over its weeks 10 to 15. The authors suggest that trainees should not be too concerned about occasional short-term training breaks in their daily lives.
Longer gaps in older adults
A 2022 meta-analysis by Grgic in the International Journal of Environmental Research and Public Health pooled six studies with eight groups of older adults. Training interventions lasted 9 to 24 weeks and detraining lasted 12 to 52 weeks. It reports that muscle size rose after training and fell after training cessation. In subgroup analyses it reports no significant decrease in muscle size after 12 to 24 weeks of cessation and a significant decrease after 31 to 52 weeks. The author concludes that loss of muscle size might be related to the duration of detraining, and that future studies are needed to establish the time course.
Why these results should not be added together
The four papers measured different things in different people. The 2013 review looked at strength outcomes across many studies, including older people and athletes. The 2011 trial measured a bench press and muscle size in 15 young men after 3 weeks, and the 2024 trial measured leg and arm exercises in 55 untrained adults after 10 weeks. The 2022 review measured muscle size only, in older adults, over 12 to 52 weeks. A 3-week result from young men does not describe a 10-week or 52-week gap, and a result in older adults does not describe younger lifters. The 2011 and 2024 trials enrolled untrained participants, and their abstracts do not describe trained lifters returning after a break.
What the abstracts do not say
Nothing in the abstracts covers what to do during a break, how to restart, or what any individual should expect. They do not compare lifting with other activity during the break. Each reports results for groups, not for any one person.
The bottom line
The 2013 meta-analysis reports that stopping resistance training reduces strength, with the size of the effect related to how long training stopped. The 2011 trial found no significant loss in muscle size or 1RM after a 3-week break in 15 young men, and the 2024 trial found that measures fell during a 10-week break in untrained adults and recovered quickly on retraining. The 2022 meta-analysis in older adults reports a significant decrease in muscle size after 31 to 52 weeks of cessation and none that reached significance after 12 to 24 weeks. Because the samples, measures and break lengths differ, the papers are summarised separately here and not combined into one rule. The figures come from abstracts.
Sources
- Effect of training cessation on muscular performance: a meta-analysis, Bosquet and colleagues, Scandinavian Journal of Medicine and Science in Sports, 2013 (abstract, PubMed), read 2 November 2026 (pubmed.ncbi.nlm.nih.gov)
- Effects of periodic and continued resistance training on muscle CSA and strength in previously untrained men, Ogasawara and colleagues, Clinical Physiology and Functional Imaging, 2011 (abstract, PubMed), read 2 November 2026 (pubmed.ncbi.nlm.nih.gov)
- Does Taking a Break Matter? Adaptations in muscle strength and size between continuous and periodic resistance training, Scandinavian Journal of Medicine and Science in Sports, 2024 (abstract, PubMed), read 2 November 2026 (pubmed.ncbi.nlm.nih.gov)
- Use It or Lose It? A meta-analysis on the effects of resistance training cessation (detraining) on muscle size in older adults, Grgic, International Journal of Environmental Research and Public Health, 28 October 2022 (abstract, PubMed Central), read 2 November 2026 (pmc.ncbi.nlm.nih.gov)
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