Does Taking a Break Matter-Adaptations in Muscle Strength and Size Between Continuous and Periodic Resistance Training.
Level 2 - randomized trial
Individual randomized controlled trial
PubMed 39364857 · doi:10.1111/sms.14739
What was done
Fifty-five healthy, untrained participants (mean age 32 ± 5 years) were randomized to either periodic resistance training (PRT; n = 20 completed) or continuous resistance training (CRT; n = 22 completed). The PRT group performed 10 weeks of resistance training (RT), followed by 10 weeks of detraining, and a second 10 weeks of RT. The CRT group completed 10 weeks of no training followed by 20 weeks of continuous RT. Training comprised twice-weekly supervised whole-body RT sessions. Outcomes included 1-repetition maximum (1RM) leg press and biceps curl, countermovement jump (CMJ) height, and ultrasound-measured muscle cross-sectional area (CSA) of the vastus lateralis and biceps brachii, assessed every 5 weeks.
What was found
Both groups showed significant increases in leg press 1RM, biceps curl 1RM, vastus lateralis CSA, biceps brachii CSA, and CMJ height from baseline (all p < 0.001), with no significant differences in final outcomes between groups. In the PRT group, 1RM strength, muscle CSA, and CMJ height decreased significantly during the 10-week detraining period (p < 0.05). However, during the first 5 weeks of retraining, PRT experienced significantly greater increases in leg press 1RM and muscle CSA than CRT did during weeks 10–15 of continuous training (p < 0.01), resulting in equivalent final adaptations.
Why it matters
This demonstrates that muscle mass and strength lost during a prolonged training break can be rapidly regained upon resuming exercise, achieving comparable end-point adaptations to uninterrupted training of equal total volume.
Limits
The abstract reports p-values but no exact means, standard deviations, or effect sizes. The sample size was modest (n = 42 completers) and limited to young, untrained individuals, meaning results may not generalize to trained athletes or older adults. Only a single 10-week break duration was tested.