There’s More to Training Volume Than Sets per Week
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TRAINING TAKEAWAY: Volume is often discussed in terms of absolute training volume (i.e., number of sets per muscle per week). However, there’s some indication that short-term changes in volume play an independent role. Thus, volume cycling via strategies like specialization phases can leverage changes in training volume and potentially provide additional practical benefits.
Introduction
Most would agree that weekly training volume (the number of sets per muscle per week) is a training variable of very high importance. However, short-term changes in training volume may have independent effects on hypertrophy.
A 2021 study by Scarpelli and colleagues provides a proof-of-concept that there’s more to training volume than just sets per week. Read on for a breakdown of this study and some important programming implications.
Study Design
Sixteen men with an average training age of 5.1 years participated in this study. One leg of each subject was randomly assigned to the Standardized Volume condition while the other leg was assigned to the Individualized Volume condition. The Standardized Volume condition performed 22 sets per week whereas the Individualized Volume condition performed 20% more volume than what was being performed before the study.
To illustrate, if a subject was performing 15 sets per week for their quadriceps before the study, one of their legs would have performed 18 sets per week (Individualized Volume condition) and their other leg would have performed 22 sets per week (Standardized Volume condition).
The Individualized Volume condition performed an average of 24 sets per week. However, this varied from 12 to 50 sets per week due to a wide range of pre-study training volumes. You can see the changes in training volume for each leg in Chart 1:
Subjects trained twice per week, and training volume was split between leg press and leg extension. Cross sectional area of the vastus lateralis was assessed via ultrasound before and after the 8 week training intervention. The researchers deemed a truly greater response if one leg within a subject grew at least one typical error of measurement more than the other leg.
Results
On average, hypertrophy was greater in the Individualized Volume condition compared to the Standardized Volume condition (+9.9% vs. +6.2%; p = 0.042). Of the sixteen subjects, ten had a greater response in their Individualized Volume leg, two had a greater response in their Standardized Volume leg, and four had similar responses. You can see the difference in response between legs for each individual in Chart 2:
What does this mean for training?
I introduced this study as one that can inform us about changes in training volume. However, using this study to claim that short-term increases in volume are more important than absolute volume is not a perfectly logical inference. Instead, these results could be explained by individualization. Before the study, subjects may have fallen into training volumes that worked well for them, making a 20% increase still reasonable. For example, a subject performing 10 sets per week may have ended up there through intuition. Then, their Individualized Volume leg that performed 12 sets per week was still reasonable whereas their Standardized Volume leg that performed 22 sets per week was way too much to recover from.
With that said, things become interesting when we consider a study by Aube and colleagues. This study randomized well-trained subjects to groups training the quads with 12, 18, or 24 sets per week. While there were no significant differences in hypertrophy between groups, the researchers collected pre-study volumes and examined how changes in volume may have influenced hypertrophy. Subjects were split into terciles based on response, which can be described as lower, middle, and higher responders. Overall, middle and higher responders tended to be those that added more sets for the study - lower responders added 1.8 ± 6.7 sets, middle responders added 4.3 ± 9.3 sets, and higher responders added 6.6 ± 12.4 sets. That said, these standard deviations are massive and indicate some of the higher responders actually decreased volume. I suspect this is due to A) especially high responders responding well no matter what and B) absolute training volume mattering (i.e., short-term changes in volume not providing a benefit if already wildly outside of an appropriate volume range). This was a non-experimental analysis, so causation can’t be inferred; however, I think it’s enough to at least peak our interest in this concept.
Put simply, whether short-term changes in volume have an independent effect on hypertrophy cannot be conclusively determined based on the existing research; however, there’s some indication it does.
If it indeed does, specialization cycles are a potential application of this concept. Specialization cycles consist of ~1-4 muscle groups being prioritized (i.e., increased training volume and often placed earlier in sessions) while all other muscle groups are programmed to allow for the selected muscle(s) to be prioritized. Notice that other muscle groups don’t have to be put on “maintenance”; they’re simply not prioritized. If needed, volume can be reduced up to ~40%, but I prefer to maintain habitual training volumes if possible.
In my coaching practice, this strategy has been a game changer for designing training programs that are practical. If a lifter seems to benefit from higher volume and/or a short-term increase in volume, we may have reason to push to say 25 sets per muscle group per week. Let’s say we want to do this for 8 muscle groups: shoulders, back, chest, biceps, triceps, quads, hamstrings, calves. (In actuality, volume for each of these muscles should be considered independently, but bear with me for this thought experiment.) That’s 200 (!) total sets per week. Even if the lifter is training five times per week, that’s 40 sets per session. Let’s be generous and say each set takes 3 minutes total (~30-60 seconds to perform the actual set and ~2-2.5 minutes of rest). That’s a 120 minute session for a total of 10 hours of training per week, and we haven’t considered warm-up time, buffer time for waiting for equipment, and inefficiencies that may come from something like a top set for a strength athlete. Further, it’s unlikely that sets in the second half of these sessions would be of high quality.
In short, even if each muscle in isolation could benefit from higher volume and/or a short-term increase in volume, time availability, set quality, and global fatigue will stop this from being a realistic strategy. Here’s how this may look in practice if pecs and quads are prioritized in a 10-week cycle and then hamstrings and biceps are prioritized in the next 10-week cycle:
Conclusion
Volume is often discussed in terms of absolute training volume (i.e., the number of sets per muscle per week). However, there’s some indication that short-term changes in volume play an independent role. Specifically, small-moderate increases in volume for a training cycle (~6-12 weeks) could support hypertrophy.
Specialization cycles can leverage changes in training volume and have the potential to lead to greater net muscle growth over time; however, more research is needed to confirm this hypothesis. Specialization cycles also provide practical benefits, such as managing global fatigue, working within time constraints, and ensuring high quality for all training.