The BEST Rep Speed For Size (New Study)

Summary

This video reviews a new meta-analysis comparing faster and slower concentric and eccentric tempos for muscle hypertrophy (14 studies, 278 subjects). Overall, there’s no clear advantage for either tempo: the pooled effect slightly favored faster tempos but was tiny (≈0.9% additive) and uncertain. Subgroup results varied by whether sets were taken to failure, and concentric data remain limited. Evidence also suggests extremely slow protocols may be less effective. Practical takeaway: tempo is a minor variable for growth—choose what you prefer and train consistently. The presenter notes tools like Alpha Progression for tailored programming.

Takeaways

• 😀 There is no clear evidence that faster or slower tempos (concentric or eccentric) have a significant advantage for hypertrophy.
• 😀 The study included 14 research papers and 278 subjects, focusing on tempos with independent variations for concentric and eccentric phases.
• 😀 In the analysis, faster tempos slightly favored hypertrophy in both the concentric and eccentric phases, but the difference is minimal (around 0.9%).
• 😀 The data shows high uncertainty with wide credible intervals, indicating that the effect size is not precisely known, and additional studies are needed.
• 😀 When training to failure, slower tempos might show a slight advantage, but this is not conclusive, and the data is uncertain.
• 😀 Faster tempos favored hypertrophy in non-failure training, especially in studies using isokinetic dynamometers, which do not represent normal free weight training.
• 😀 A general recommendation is that either faster or slower tempos are acceptable for hypertrophy, with no strong evidence for one being better than the other.
• 😀 Rep tempo (concentric/eccentric) is not a major variable for hypertrophy compared to other factors like training load, effort, and progression.
• 😀 Training to failure and training intensity remain key for muscle growth, regardless of whether the tempo is slow or fast.
• 😀 There is evidence against extremely slow training tempos, especially with lighter loads, which may not be ideal for hypertrophy. Regular tempos (e.g., 1-2 second concentric/eccentric) seem more effective.
• 😀 Overall, the tempo debate is nuanced, and while research continues, current evidence suggests that training with either faster or slower tempos will lead to similar muscle growth, provided you're training to or near failure.

Q & A

What is the primary goal of the meta-analysis in the video?

The primary goal of the meta-analysis was to examine whether faster or slower tempos, during the concentric and eccentric phases of training, have a greater effect on muscle hypertrophy.

Why were studies with both faster concentric and eccentric tempos excluded from the analysis?

Studies that included both faster concentric and eccentric tempos in one group were excluded because the analysis aimed to focus only on studies that independently manipulated either the concentric or eccentric tempo separately.

What is a 'forest plot' and how is it used in this meta-analysis?

A forest plot is a graphical representation of individual study results in a meta-analysis. Each study’s effect estimate is shown with a dot, and the plot also includes a combined metaanalytic result along with a 95% credible interval to show the uncertainty of the estimates.

What does a 95% credible interval tell us about the study’s results?

A 95% credible interval indicates the range within which the true effect is likely to fall, with 95% confidence. A wide interval suggests a high level of uncertainty, while a narrow interval suggests more precise estimates.

What were the findings of the meta-analysis regarding eccentric tempos?

The meta-analysis found that faster eccentric tempos slightly favored hypertrophy, but the effect was minimal (about 0.9% greater muscle growth), and the uncertainty in the data suggested no clear advantage for either faster or slower eccentric tempos.

How did the subgroup analysis on training to failure vs. non-failure impact the eccentric tempo results?

The subgroup analysis showed that for training to failure, slower eccentric tempos seemed to have a slight advantage, whereas for non-failure training, faster eccentric tempos were slightly favored. The differences, however, were still small and uncertain.

What was the key finding regarding concentric tempos?

The analysis of concentric tempos showed a slight favor for faster tempos, but due to limited data and high uncertainty, no definitive conclusions could be drawn about their superiority for hypertrophy.

Why can’t we make definitive conclusions about the optimal tempo for hypertrophy from this meta-analysis?

The lack of precision in the data, the uncertainty in the credible intervals, and the limited number of studies on trained individuals mean we cannot definitively conclude which tempo—faster or slower—is superior for hypertrophy.

What did previous research indicate about the relationship between tempo and hypertrophy?

Previous research, including older meta-analyses and reviews, suggests that training to failure with a wide range of tempos (fast or slow) is likely similarly effective for hypertrophy, provided the sets are taken to failure or near failure.

What is the takeaway about super-slow training tempos for hypertrophy?

Super-slow training tempos (e.g., 10 seconds concentric and 4 seconds eccentric) might not be ideal for hypertrophy, as one study found better results with normal tempos (1-2 seconds concentric and eccentric) in terms of muscle fiber growth, despite using lighter loads.