Drop Sets: Same Gains, Less Time?
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TRAINING TAKEAWAY: Drop sets offer a time efficient alternative to traditional straight set training. However, it may require more sets to maximize outcomes while doing so.
Background
Discussions in the evidence-based community are often centered around maximizing outcomes. Lifters aim to manipulate their training and nutrition practices to squeeze out every ounce of additional progress, even when effects are small. However, there is another lens we can view training from: efficiency. Efficiency can be defined as the greatest effect to time investment ratio. For example, getting optimal results (100%) in 10 hours a week is less efficient than 80% of optimal results in only 5 hours a week.
One of the most popular strategies to increase the efficiency of training is to perform drop sets. Broadly speaking, a drop set is when an initial set is performed, immediately followed by additional sets with a reduced load (e.g., 100 kg immediately reduced by 20% to 80 kg then reduced by an additional 10% to 72 kg). The idea with drop sets is that a similar stimulus can be achieved in a fraction of the total training time, thereby improving efficiency. Thankfully, a new meta-analysis by Coleman and colleagues allows us to take a closer look at how drop sets impact training adaptations.
Study Overview
As with all meta-analyses, it's important to start with the inclusion criteria. The authors systematically searched for all studies that:
Had a randomized study design
Directly compared drop sets to traditional training
Assessed changes in strength (dynamic and isometric) and/or hypertrophy (ultrasound, computed tomography [CT], magnetic resonance imaging [MRI])
Had a training protocol that lasted at least 6 weeks
Involved apparently healthy subjects
Using this criteria, 5 studies were analyzed and are briefly summarized in the table below.
* = unclear how many sessions per week
Results
When pooling the effects of these studies, the overall point estimates were a trivial standardized mean difference of 0.07 [95% CI: -0.14, 0.29] and 0.08 [95% CI: -0.08, 0.24] in favor of drop sets for strength and hypertrophy, respectively. Heterogeneity between studies was minimal for both strength and hypertrophy (I2 = 0%). In other words, there were comparable gains observed between drop sets and traditional straight set training. Upon looking into each of the individual studies, the strength results from Fink et al. and a secondary analysis of Leg Press 1RM by Enes et al. were not included. Including these data points would likely balance out the findings even more, as both effects were in favor of traditional sets. I’ve included these effects in the forest plots so you can see how they may impact the overall estimate, although they were not included in the analysis by Coleman et al. Finally, one outlier was identified for each strength and hypertrophy; however, a leave-one-out sensitivity analysis did not alter the interpretation of the results. These effects indicate that drop sets result in comparable gains in muscle strength and size to traditional straight set training. However, as I alluded to, the question we care about is whether drop sets improve training efficiency.
Examining Efficiency
I think there are two primary ways we should quantify training efficiency: per unit time and per set. The former represents absolute efficiency, whereas the latter describes relative efficiency (i.e., how productive each set is).
Per Unit Time:
When considering gains in strength and hypertrophy per unit of time investment, the advantage of drop sets really shines. Looking at the table that breaks down each study included, I estimated an average of ~53% less training time per week. Given that the majority of studies fail to reveal a difference between conditions, this is a huge win. Further, so long as the peak load is equated in the drop set conditions, strength gains are often comparable, although there is probably a threshold where differences in average load matter. Ultimately, this demonstrates that drop sets seem to have greater absolute efficiency than straight sets as less time is required to achieve a similar stimulus.
Per Set:
However, when we flip the script to relative efficiency, things change a bit. You may recall that there is a dose-response relationship between training volume (sets per week), hypertrophy, and (albeit to a lesser extent) strength. Thus, conditions that use a greater amount of sets generally lead to better outcomes. Again looking at the study breakdown table, you can see that the drop set conditions completed an average of 32% more sets than traditional straight set training. To be clear, I am defining each “drop” as a separate set, as they each are >30% of 1RM and almost certainly at least 5 reps per set. Given that the meta-analytic estimate sits very close to 0, particularly for hypertrophy, this may indicate less adaptation per set. Now, I want to be very clear that this isn’t a perfect logical inference. It could be that the current studies simply find a threshold of adaptation in which additional set volume doesn’t result in greater gains, rather than drop sets actually being less efficient. In other words, these groups do perform more sets, but they may not need to. To confirm that drop set are indeed less efficient per set, we would need a study that includes the following groups:
Traditional straight sets (e.g., 4 sets of 8 reps)
Set volume equated drop sets (e.g., 1 main set, followed by 3 drop sets)
Non-set volume equated drop sets (e.g., 1 main set, followed by 5 drop sets)
The reality is, we simply don’t have a study that examines this to my knowledge. Thus, we’ll need to use some other research to come to tentative conclusions. In my opinion, given that shorter rest periods seem to blunt hypertrophy but additional sets can make up for this, it's reasonable to assume this is also the case for drop sets. As of right now, I would operate on the assumption that drop sets are slightly (but meaningfully) less efficient per set. Practically, it may be wise to equate volume load or total repetitions to a similar straight set protocol in order to maximize outcomes.
Summary
If you’re looking to improve your absolute training efficiency and consequently spend less time in the gym, drop sets can be an awesome tool. Given some of the nuances in the way the protocols are designed in the research, it's important to configure your drop-set protocols carefully. While more data is needed, we can tentatively conclude that drop sets are a bit less productive per set; thus, more sets may need to be performed to maximize outcomes.
