Effects of Detraining on Muscle Strength and Hypertrophy Induced by Resistance Training: A Systematic Review

Abstract

A detraining period after resistance training causes a significant decrease in trained-induced muscular adaptations. However, it is unclear how long muscle strength and hypertrophy gains last after different detraining periods. Thus, the present systematic review with meta-analysis aimed to evaluate the chronic effects of detraining on muscle strength and hypertrophy induced by resistance training. Searches were conducted on PubMed, Scopus, EBSCO, CINAHL, CENTRAL, and Web of Science. The difference in means and pooled standard deviations of outcomes were converted into Hedges’ g effect sizes (g). Twenty randomized and non-randomized trials (high and moderate risks of bias, respectively, and fair quality) were included for qualitative analysis of muscle strength and hypertrophy, while only two studies were included in the meta-analysis for maximum muscle strength. The resistance training group presented a significant increase in one-repetition maximum (1RM) chest press (g: 4.43 [3.65; 5.22], p < 0.001) and 1RM leg press strength (g: 4.47 [2.12; 6.82], p < 0.001) after training. The strength gains observed in the resistance training group were also maintained after 16–24 weeks of detraining (g: 1.99 [0.62; 3.36], p = 0.004; and g: 3.16 [0.82; 5.50], p = 0.008; respectively), when compared to the non-exercise control group. However, 1RM chest press and leg press strength level was similar between groups after 32 (g: 1.81 [−0.59; 4.21], p = 0.139; and g: 2.34 [−0.48; 5.16], p = 0.104; respectively) and 48 weeks of detraining (g: 1.01 [−0.76; 2.79], p = 0.263; and g: 1.16 [−1.09; 3.42], p = 0.311; respectively). There was not enough data to conduct a meta-analysis on muscular hypertrophy. In conclusion, the present systematic review and meta-analysis demonstrated that, when taking random error into account, there is no sufficient high-quality evidence to make any unbiased claim about how long changes in muscle strength induced by RT last after a DT period. Moreover, the effect of different DT periods on muscle hypertrophy induced by RT remains unknown since there was not enough data to conduct a meta-analysis with this variable.

“You can't shoot another bullet until you've reloaded the gun”: Coaches' perceptions, practices and experiences of deloading in strength and physique sports

“…A meta-analysis by Bosquet et al ( 79 ) indicated that maximal force declined at a similar rate with a cessation period of <7 and 7–14 days, whilst the decrease only became significant after the third week of cessation. Whilst there is a considerable amount of literature investigating the effects of detraining on measures of muscular strength, by contrast, the effect of detraining on muscle hypertrophy is under-researched ( 80 ), especially in the short-term (i.e., <4 weeks). Peripheral adaptations, such as changes in muscle CSA and tendon properties, appear to decay faster than muscle strength and neural activation ( 81 ).…”

Deloading Practices in Strength and Physique Sports: A Cross-sectional Survey

“…Interestingly, a recent article highlighted that a one-week period of no training at the midpoint of a 9-week resistance training programme negatively impacted lower body strength – but not hypertrophy, power or local muscular endurance – when compared with continuous training [ 38 ]. This suggests that the complete cessation of training might be detrimental for maximal strength where neural adaptations and exposure to load are an important antecedent to performance [ 39 ]. The periodic absence of training within a short-to-medium term programme might therefore be detrimental to some trainees, and more work might need to be done to understand optimal deloading strategies to manage training load for purposes such as maximal strength training, hypertrophy, and rapid force production – a ‘one-size fits all approach’ would appear to conflict with the emerging experiential and empirical evidence.…”

Detraining among Athletes—Is Withdrawal of Adaptive Cardiovascular Changes a Hint for the Differential Diagnosis of Physically Active People?

“…The greater afterload results in an increase in arterial pressure and more concentric remodeling of the heart. Systematic training also leads to hypertrophy of the working skeletal muscles, a change in the type of muscle fibers and an increase in dynamic strength [4].…”