Blocks, Undulation and Why It Barely Matters
Introduction
If you've decided you want some structure, the next question appears: which model? Linear, block, daily undulating, weekly undulating. Each has advocates, physiological arguments and studies in its favour.
The short answer — and the one least often given — is that the difference between models is small compared with the difference between following one and following none.
Choose the model you'll actually follow. That's by far the most decisive variable among the ones you're comparing.
The four models
Classic linear. Volume falls and intensity rises across the weeks: you start with sets of twelve and finish with sets of four. It's the original model and the simplest to understand.
Block. Each block of three to six weeks concentrates on one capacity: an accumulation block with more volume, an intensification block with more load, a taper. They're sequenced to reach a peak.
Daily undulating. Within the same week, each session works a different range: Monday heavy with few reps, Wednesday moderate, Friday lighter with more reps.
Weekly undulating. The same, but the variation runs week to week instead of session to session.
What the comparisons show
Here's the point that settles the discussion. When these models are compared against each other with total volume and intensity equated, the results are very similar.
Grgic and colleagues' meta-analysis comparing linear with daily undulating periodization for hypertrophy found no significant differences between them. Strength reviews sometimes find a slight advantage for undulating, with small, inconsistent effect sizes across studies.
In other words: there's no superior model. There's a set of reasonable ways to organize the same work.
What does appear consistently in the literature is the usual: total volume, progression and proximity to failure explain far more of the variance than the way the weeks are arranged.
So how do you choose?
Since physiology doesn't decide, practicality does:
Choose linear if you like simplicity and don't mind the last weeks being hard. It's the easiest to program and to follow.
Choose undulating if repeating the same scheme bores you, if consecutive weeks of very heavy work bother you, or if you train each muscle group two or three times a week and want those sessions not to be identical.
Choose blocks if you have a target date. It's the model that makes most sense when you need to peak.
Choose none if you don't yet have stable progression. Double progression plus a log is enough for quite a while.
A practical advantage of undulating
Worth mentioning because it's real and not physiological: variation between sessions protects adherence. Three identical sessions a week get heavy, and one lighter session in between provides a sense of recovery that helps you reach Friday.
It also distributes joint stress: not every session loads the same structures the same way.
Neither of those reasons appears in hypertrophy studies, and both influence whether you're still training in March.
What to respect whatever the model
1. Total weekly volume should sit in a reasonable range per muscle group. 2. Something has to increase across the block; otherwise it's variation without progression. 3. Proximity to failure must be sufficient in the sets that count. 4. There has to be a moment of reduced load every so often. 5. The log must allow comparison of equivalent sessions across weeks.
If your plan meets those five points, the model's name is a label.
Common mistakes
Searching for the optimal model. Time spent on the lowest-impact decision you'll make.
Changing model every block. It prevents knowing whether anything worked and resets technical learning.
Copying an elite model. Athletes' plans assume volumes and frequencies you won't sustain.
Undulating without progressing. Rotating heavy, medium and light without any of them rising over time is going in circles.
Confusing model with program. The model says how load is distributed; the program says which exercises, how many sets and how you progress. The second matters more.
Conclusion
Linear, block and undulating produce very similar results when volume and intensity are equivalent. The choice should be made on preference and schedule, not physiology.
Make the decision today and don't revisit it: pick the model you believe you'll follow for three straight months and write it next to your plan. The time you were going to spend comparing models pays off far more invested in making sure volume and progression are right.
References
- Grgic, J., et al. (2017). Effects of linear and daily undulating periodized resistance training programs on measures of muscle hypertrophy. PeerJ, 5.
- Williams, T. D., et al. (2017). Comparison of periodized and non-periodized resistance training on maximal strength: A meta-analysis. Sports Medicine, 47(10).
- Harries, S. K., Lubans, D. R., & Callister, R. (2015). Systematic review and meta-analysis of linear and undulating periodized resistance training programs on muscular strength. Journal of Strength and Conditioning Research, 29(4).
- Kiely, J. (2012). Periodization paradigms in the 21st century: Evidence-led or tradition-driven? International Journal of Sports Physiology and Performance, 7(3).
- Schoenfeld, B. J., et al. (2017). Dose-response relationship between weekly resistance training volume and increases in muscle mass. Journal of Sports Sciences, 35(11).