Gaining more from doing less? The effects of a one-week deload period during supervised resistance training on muscular adaptations

Abstract

Background: Based on emerging evidence that brief periods of cessation from resistance training (RT) may re-sensitize muscle to anabolic stimuli, we aimed to investigate the effects of a 1-week deload interval at the midpoint of a 9-week RT program on muscular adaptations in resistance-trained individuals.

Methods: Thirty-nine young men (n = 29) and women (n = 10) were randomly assigned to 1 of 2 experimental, parallel groups: An experimental group that abstained from RT for 1 week at the midpoint of a 9-week, high-volume RT program (DELOAD) or a traditional training group that performed the same RT program continuously over the study period (TRAD). The lower body routines were directly supervised by the research staff while upper body training was carried out in an unsupervised fashion. Muscle growth outcomes included assessments of muscle thickness along proximal, mid and distal regions of the middle and lateral quadriceps femoris as well as the mid-region of the triceps surae. Adaptions in lower body isometric and dynamic strength, local muscular endurance of the quadriceps, and lower body muscle power were also assessed.

Results: Results indicated no appreciable differences in increases of lower body muscle size, local endurance, and power between groups. Alternatively, TRAD showed greater improvements in both isometric and dynamic lower body strength compared to DELOAD. Additionally, TRAD showed some slight psychological benefits as assessed by the readiness to train questionnaire over DELOAD.

Conclusion: In conclusion, our findings suggest that a 1-week deload period at the midpoint of a 9-week RT program appears to negatively influence measures of lower body muscle strength but has no effect on lower body hypertrophy, power or local muscular endurance.

Keywords: Detraining; Hypertrophy; Muscle endurance; Resensitize; Strength.

Figure 1. Consort diagram.

CONSORT flow chart of the data collection process.

Figure 2. Muscle morphology.

Posterior distributions of group differences for body composition and muscle morphological outcomes expressed as standardized mean difference effect sizes. Negative values favor control and positive values favor the inclusion of a detraining period. Effect sizes were calculated by dividing group differences by the pooled baseline SD. Small (0.15), medium (0.30) and large (0.50) thresholds derived for strength and conditioning interventions are presented with gray lines.

Figure 3. Strength performance.

Posterior distributions of group differences for performance outcomes expressed as standardized mean difference effect sizes. Negative values favor control and positive values favor the inclusion of a detraining period. Effect sizes were calculated by dividing group differences by the pooled baseline SD. Small (0.15), medium (0.30) and large (0.50) thresholds derived for strength and conditioning interventions are presented with gray lines.