The Effects of a One-Week Training Deload on Muscular Adaptations

Although there is compelling evidence on the benefits of resistance training, it’s been suggested that continuous bouts of intense resistance training are associated with fatigue.
 
Deloading is a period (∼1 week) of decreased training volume, load and/or intensity of effort.
 
It is a common strategy used by coaches and athletes to counteract accumulated fatigue and diminish the potential for nonfunctional overreaching. Non-functional overreaching is a transient decrement in performance capacity despite increased training stress which restores within weeks⁽¹⁾.   

A recent study using the International Delphi Consensus technique defines deloads as “a period of reduced training stress designed to mitigate physiological and psychological fatigue, promote recovery, and enhance preparedness for the subsequent training cycle”⁽²⁾.
 
It has been speculated that the diminished rate of muscular adaptations typically seen in the latter phases of resistance training programs may also be negated by implementing a detraining period.

This detraining period may attenuate the reduction in anabolic signaling protein phosphorylation usually seen with continuous bouts of resistance training, as well as upregulate genes associated with muscle growth⁽³⁾.  

The idea is that this period facilitates a “re-sensitization” of muscle hypertrophic stimuli.

In addition, the detraining period is beneficial to hormonal balance as evidence shows that testosterone increases and cortisol decreases following a detraining period⁽⁴⁾.  

Although findings are intriguing on the benefits of deloading, current research on the effects of detraining do not reflect the typical practices of those in the lifting community.

Research typically uses about 3-week periods of detraining whereas in the real-world; detraining is typically about 1 week.

There is also no evidence on the direct potentiating effects of deloads on successive training cycles in resistance trained individuals. In order to answer these questions, a recent study investigated the effects of deloading, implemented as a 1-week period of cessation from training at the midpoint of a 9-week resistance training program, on muscular adaptations in resistance-trained individuals⁽⁵⁾.

Findings and interpretation of the study

This is the first study to directly assess the potential to enhance the efficacy of a 1-week deload period on muscular adaptations. Results indicate a 1-week deload of no training at all has a minimal impact on measures of muscle hypertrophy, endurance, or power in the setting of a 9-week training block.

There was no evidence of a prospective positive effect to re-sensitization of the muscle. Interestingly, while both groups increased strength, the group without a deloading week experienced moderate benefits in measures of both isometric and dynamic strength.

Muscle growth

Both groups increased muscle size over the 9-week duration of the study, with similar between-group increases observed in all measurements. These findings indicate that although 1 week of cessation of training does not attenuate the hypertrophic adaptations seen in the first half of a 9-week training block; it also does not enhance results over time. This finding is generally in agreement with other research⁽⁶⁾.

An interesting finding was around motivation to train.

Although no objective measures of fatigue or anabolic signaling were meaured, participants anecdotally often reported feeling lethargic after the deloading period rather than refreshed. This could be due to the total cessation of training during this 1-week deload period.

Most practical applications utilize a deload period which involves reduced training volumes and/or intensities.

It is plausible that a reduced rather than total abstinence from training would allow for the dissipation of fatigue without bringing about a feeling of lethargy upon return.

Muscle strength

Although both groups showed enhanced dynamic and isometric strength; the group that did not deload demonstrated superiority in these measures. These findings are particularly surprising considering the extensive use of deloads in athletes involved in strength sports such as powerlifting and weightlifting.

An important notation is that the aim of the resistance training protocol in this study was not to maximize strength, but rather to maximize hypertrophy.

Therefore, it is feasible that deloads may present different effects when utilizing a resistance training protocol consistent with that of strength athletes. It also is unknown if a brief period of reduced training, rather than total cessation, may attenuate the blunting of strength gains or perhaps even potentiate improvements.

Study Limitations

There are multiple limitations and considerations that must be considered when drawing practical conclusions from this research.  

Below are some main considerations to keep in mind about this study:

• This research was conducted on young men and women with a minimum of 1 year training experience; therefore, these findings can’t be generalized to other populations (i.e., untrained, individuals over age 40, adolescents, etc.).
• The use of smith machine for strength assessments.  Participants were not required to have training experience in the smith machine squat; therefore, increases in 1RM strength may be attributed to neural adaptations not likely seen in induvial who routinely perform smith machine squats.
• Metrics assessed in this study were specific to the lower body musculature; therefore inferences regarding the effect of deloading on the upper body muscles cannot be drawn.
• These findings are from a short, 9-week training block and a high training volume (90 weekly sets) and relatively low frequencies (i.e., each muscle trained only twice weekly). The effects of deload periods within the context of longer training periods as well as higher weekly training volumes and frequencies are not well elucidated.
• The potential re-sensitization effect of deloads could not be made from this research because markers of anabolic signaling were not measured.
• These results are specific to a deload involving a cessation of resistance training. In real-world practical application, deloads can employ a wide range of strategies designed to reduce training load, volume and/or intensity as opposed to abstention. Future studies should seek to investigate the effects of different deload approaches on muscular adaptations.

Summary

A 1-week cessation deload period at the midpoint of a 9-week training block produced similar enhancements in lower body muscle size, endurance and power when compared to a continuous training block.

The continuous training group demonstrated superior improvements in lower body strength compared to deloading. We can infer that when trying to optimize strength; periods of complete training cessation should be used more sparingly.

I think more research is needed to fully understand how deloads can be utilized to maximize muscular adaptations as well as determine which populations would benefit the most from these deloading periods.

You can learn more about the minimum effective training dose for strength and size here.


References
    1.    Meeusen R, Watson P, Dvorak J: The brain and fatigue: new opportunities for nutritional interventions? J Sports Sci 24:773-82, 2006
    2.    Bell L, Strafford BW, Coleman M, et al: Integrating Deloading into Strength and Physique Sports Training Programmes: An International Delphi Consensus Approach. Sports Med Open 9:87, 2023
    3.    Jacko D, Schaaf K, Masur L, et al: Repeated and Interrupted Resistance Exercise Induces the Desensitization and Re-Sensitization of mTOR-Related Signaling in Human Skeletal Muscle Fibers. Int J Mol Sci 23, 2022
    4.    Hortobágyi T, Houmard JA, Stevenson JR, et al: The effects of detraining on power athletes. Med Sci Sports Exerc 25:929-35, 1993
    5.    Coleman M, Burke R, Augustin F, et al: Gaining more from doing less? The effects of a one-week deload period during supervised resistance training on muscular adaptations. PeerJ 12:e16777, 2024
    6.    Ogasawara R, Yasuda T, Ishii N, et al: Comparison of muscle hypertrophy following 6-month of continuous and periodic strength training. Eur J Appl Physiol 113:975-85, 2013