In December 2019, Mike Israetel and his co-authors published a paper in the Strength and Conditioning Journal titled ‘Mesocycle Progression in Hypertrophy: Volume Versus Intensity’.
The paper argued that over a 4 to 12 week training block, athletes should prioritize adding sets rather than adding weight to the bar.
Less than a year later, in October 2020, researchers Brian Miner, Eric Helms, and Jacob Scheppis published a formal letter to the editor challenging the paper’s central claims. Their critique not only questioned the evidence behind Israetel’s recommendations but also highlighted several conceptual issues with how the principles were applied. Israetel later responded, offering clarifications and, in some cases, notable concessions.
At the core of the disagreement was the paper’s interpretation of the relationship between training volume and hypertrophy. Miner and colleagues argued that the commonly cited dose-response relationship is based on comparisons of total training volume over an entire study period, not on week-to-week increases within a program.
As they pointed out, no studies have directly compared a group that progressively increases weekly sets to one that keeps volume constant while equating total workload. As a result, the recommendation to add sets each week does not logically follow from the existing evidence.
They also took issue with how progressive overload was framed. The letter stated: “Implicit in this article is the assumption that progression should occur on a week-to-week basis, which may be a misapplication of the progressive overload principle.”
Instead, they argued that progressive overload should be viewed as a reactive process, driven by an athlete’s adaptation, rather than a fixed, calendar-based prescription.
Another key point of contention was the concept of maximum recoverable volume (MRV) as a target for hypertrophy. Miner et al. wrote: “To our knowledge, there is no evidence of or theoretical reason to believe that workload capacity, MRV, is related to optimal volume for hypertrophy.”
They referenced research suggesting that moderate training volumes are sufficient for muscle growth, while higher volumes such as 14 to 28 sets per week often fail to produce additional benefits.
The critique extended to the paper’s stance on training intensity. Israetel’s article suggested that lifting heavier weights may not be the most effective strategy, but the response pushed back strongly.
It stated: “No data support that 6, 8, and 10 RMs are decreasingly fatiguing or increasingly stimulative.” In practice, sets performed within a broad 6–20 repetition range, when matched for effort (reps in reserve), tend to produce similar hypertrophy outcomes.
In fact, programs that incorporate progressive loading have been shown to yield greater increases in fat-free mass compared to reverse linear periodization models.
Safety was another concern. The critics noted that rapidly increasing training volume, such as doubling weekly sets from 10 to 20 in a short period, could elevate injury risk. This aligns with research on the acute-to-chronic workload ratio, which links sudden spikes in training load to a higher likelihood of injury.
In his response, Israetel acknowledged several limitations in the original paper. He clarified: “It is not our contention that MRV is the optimal volume for hypertrophy. In fact, it is likely above the optimal volume for long-term hypertrophy.”
He also admitted that the idea of adding sets weekly was “implied” and primarily intended as a simplified example rather than a strict prescription. Additionally, he described the progression model as speculative, noting that the article aimed to propose a framework in an area where direct evidence is still lacking, and directed readers toward more detailed guidance in commercial materials.
As an alternative, Miner and his co-authors recommended an autoregulated double progression model. This approach begins with a manageable volume, typically around 8 to 12 sets per muscle group, and emphasizes increasing load only when performance improves.
