How Low Can You Go? More Volume May Be Needed To Maintain Muscle Size With Increasing Training Age.
Only have a second? Check out the takeaway below. Have 5 minutes? Check out the rest of the newsletter.
TRAINING TAKEAWAY: Trained individuals should likely be more conservative with decreases in training volume when aiming to maintain muscle size than their untrained counterparts. While direct evidence is limited, volume load reductions of 66% or smaller are a decent place to start.
Background
You’ve probably heard this claim many times within the evidence-based fitness community:
“It takes much less training volume to maintain adaptations than create new ones.”
While this is accurate, the evidence it rests upon is weaker than most realize. In this issue of the newsletter, we’re going to use a new study by Braz et al. as a jumping off point to investigate how much trained individuals can reduce their training volume and still maintain muscle size.
Study Overview
The study from Braz and colleagues used a within-participants unilateral design. This means that each participant served as their own control as each of their legs were initially assigned to one of the two conditions. Twenty two trained participants (mean training age = 3.3 years; mean pre-study quadriceps volume = 27.4 sets per week) were included. There was a Low Frequency condition that trained twice per week and a High Frequency condition that trained 4 times per week. Importantly, outcomes between these two conditions were examined after a fixed number of training sessions (16); thus, the Low Frequency protocol lasted 8 weeks and the High Frequency protocol lasted 4 weeks. For the rest of this newsletter, we’re going to focus on the High Frequency condition as it's the most relevant to the discussion regarding volume reduction. Although it's not entirely clear in the methods, it seems each training session consisted of 12 sets of unilateral knee extension performed to concentric failure with 60 seconds of rest. This resulted in the High Frequency protocol consisting of 48 sets per week.
Following their 4-week protocol, the High Frequency limbs (n = 21; one participant from the initial sample dropped out) were then split into two groups for 4 more weeks:
2x per week training (24 sets per week, -50% volume from the previous 4 weeks)
Detraining (no training)
Muscle size of each of the four heads of the quadriceps at both proximal and distal regions was assessed before and after this second 4-week period using B-mode ultrasound. These groups allow us to evaluate the influence of decreased training volume in trained individuals.
Results
To summarize the results succinctly, a 50% decrease in training volume allowed for better muscle growth/retention than detraining (Figure 1). When examining Figure 1, it’s important to note that the most relevant data are likely from the rectus femoris as the leg extension was used, and we know from other data that the leg extension primarily grows the rectus femoris due to its biarticular nature (i.e., crosses two joints). In the present study, there was a significant difference (p = 0.001) in the changes in muscle thickness observed in the rectus femoris, with increases seen in the group dropping volume by 50% and decreases seen in the detraining group. This suggests that trained individuals may be able to maintain, or even slightly gain, muscle size with about half of the training volume used to get those adaptations. However, an important caveat is that while these participants were training with 48 sets per week for 4 weeks, their habitual volumes prior to the study were just slightly (~14%) higher at 27.4 sets/week compared to the reduced volume of 24 sets/week. It could have been the case that 48 sets per week was an unnecessarily high workload and dropping volumes got them closer to a number of sets that was more appropriate - allowing for continued growth.
While this study does help to inform the answer to how much volume is needed to maintain muscle size in trained individuals, we’ll need to consult other literature to get the full picture.
Bickel et al. (2011)
It wouldn’t be a proper discussion of maintaining adaptations from resistance training without discussing a study by Bickel and colleagues. This study gets mentioned a ton, with the takeaway that focuses on the young participants often stated as:
“Young individuals can maintain muscle size on as little as 1/9 the training volume initially performed.”
At face value, I think this takeaway is supported by the results of the study. Thirty nine young individuals (ages 20-35) initially performed a 16-week progressive resistance training program (3x per week, 3 sets per session). After the initial program, 28 of these participants were then randomized into one of 3 conditions which lasted for 32 weeks:
1/3 maintenance dose (1x per week, 3 sets per session)
1/9 maintenance dose (1x per week, 1 set per session)
Detraining (0x per week, 0 sets per session)
You can see in the figure that the 1/9 maintenance dose was able to roughly preserve mean fiber area (MFA) compared to the post test values of the initial training intervention, whereas the 1/3 maintenance dose may have even continued to gain muscle. This confirms that adaptations can be maintained with less volume than originally performed, but I think these results are often over-extrapolated to well-trained populations. The participants in the Bickel study had performed no resistance training for the last 5 years. Given that most people would call individuals who inconsistently go to the gym as “untrained” in the grand scheme of things, this meaningfully impacts the interpretations of these results. I’d change the takeaway to:
“Young untrained individuals can maintain muscle size on as little 1/9 the training volume initially performed, within their first year of training progressively.”
To better investigate this topic in trained individuals, we can look towards a collection of studies that examine the effects of tapering (i.e., short term volume reductions) on muscle size.
Tapering Studies
There is a decent body of evidence that examines what happens when well trained individuals reduce their training volume. I went through all the studies I am aware of with the following inclusion criteria:
Trained participants (i.e., >1 year of resistance training experience)
Performed training with a reduced dose of resistance training, rather than training cessation
Took measurements of muscle size (specifically vastus lateralis) before and after the tapering period with a direct measurement (e.g., B-mode ultrasound)
The results of the 8 studies I found are summarized in the below figure:
Ultimately, due to the nature of these studies (multiple case studies are included) there aren’t many strong conclusions we can make. Rather, it is important to point out there are multiple documented cases of decreases in muscle size (some of which are pretty substantial) when training volume is decreased by amounts similar to the Bickel study (i.e., 66-89% decrease in volume load) for only 2-4 weeks. Because these observations confirm that meaningful muscle loss is possible, I would be more conservative with recommendations for trained individuals. Thus, a decent ballpark is decreasing volume load by less than 66% when aiming to maintain muscle size.
Another limitation is that there are other factors that can influence measurements of muscle size with ultrasound, namely muscle swelling or edema. It could be that reduced training volume during tapering affects the ultrasound measurements rather than any “real” decreases in muscle mass. I don’t think this is likely to explain everything we see here (as some of the changes are rather large), but it's a potential contributor.
Alternatively, it may not always be a priority to maintain muscle size. If this is the case, and some loss of muscle mass is not a deterrent, training volume can be decreased to a larger extent. On a positive note, larger reductions in training volume may increase the likelihood of physiological resensitization, although it’s unknown whether this leads to superior outcomes in the long-term. Finally, quantifying training volume is always challenging. In many of these studies, volume load is reported, and quantifying the number of sets performed (which may be practically preferred) isn’t always possible. However, at a fixed repetition range and RIR target, volume load should apply roughly similar to sets. Additionally, it’s important to consider what a change in volume is relative to. Many of these studies periodized training with considerable fluctuations in volume. I decided to quantify decreases in volume load relative to the peak weekly volume load performed in the training program. However, if you looked at changes relative to the weekly volume load performed immediately before the taper, the numbers would be substantially lower. Thus, this may be grounds to be even more conservative with volume reductions when aiming to maintain muscle size.
Practical Applications
A lifter may want to decrease training volume for a variety of reasons (e.g., time constraints, injury, specializing another muscle(s)/lift(s), etc.) with an aim to maintain as much muscle as possible. There isn’t a ton of direct evidence on this topic in well-trained individuals, but I would be more conservative than commonly stated thresholds. A decent ballpark range to start is to decrease volume load by less than 66%.