Linear traditional (TP) and undulating (UP) periodization are two common approaches to developing strength and athletic qualities.
This meta-analysis asks which model produces better outcomes for strength, power, endurance, and hypertrophy.
Periodization choices compound over months so even small effects matter for athletes cycling through strength blocks.
Should you vary intensity/rep zones frequently (UP) or progress in longer phases (TP) to gain more 1RM strength and muscle?
What Did the Researchers Do?
Design
- Systematic review and meta-analysis, following Cochrane guidance. 25 studies included; training lasted 6–16 weeks with 2–4 sessions/week.
- 592 participants (400 male, 192 female); mostly adults; ~60% with prior RT experience.
Interventions
- TP used phased blocks (e.g., 4–6 week emphasis shifts).
- UP varied zones more frequently (daily/weekly bi-weekly). 🔁
Outcomes
- 1RM (bench, squat, leg press, others)
- Muscular endurance (RMs)
- Power (jumps/throws)
- Isometric strength
- Hypertrophy via imaging (US/MRI).
The researchers used random-effects models, subgroup and sensitivity tests (training status, authors’ periodization definitions vs. standardized definitions, and volume-matched studies).
What were the results?
Max Strength (1RM)
- Pooled analysis favored UP with a small positive effect (SMD ≈ 0.22; p = 0.005). Subgroups by lift (bench, squat, leg press) were not individually significant.
- When total work was matched, the advantage for UP roughly doubled (SMD ≈ 0.47; p = 0.002).
Muscular Endurance (RMs)
- No pooled difference; a sensitivity analysis using standardized periodization definitions showed a slight UP edge.
Power & Isometric Strength
- No differences between UP and TP.
Hypertrophy
- No difference between models using imaging outcomes.
What Does This Mean?
Max Strength
- For max strength gains over 6–16 weeks, UP has a measurable edge, especially when total work is equated.
- This likely reflects better stimulus-recovery distribution across the week rather than greater volume.
Power and Size
- Power and size do not depend on periodization style in the short term.
- If power or hypertrophy is your primary KPI in a brief block, model choice matters less than execution and load management.
Definitions Matter
- Cleaner classification of TP vs UP sharpened the signal for strength and, in one analysis, endurance. Standardize your templates.
Limitations
- Short duration ⮕ Longest study was 16 weeks; Periodization is a long-game strategy, and conclusions beyond 4 months remain uncertain.
- Methodological gaps ⮕ Inconsistent dietary control, concurrent training in some studies, limited blinding, and uneven reporting on volume matching.
Coach’s Takeaway
- Program strength blocks with UP when 1RM is the main KPI, especially if total work is matched across groups.
- Keep power work model-agnostic in short blocks; prioritize intent, load, and exercise selection.
- Standardize your periodization templates and volume accounting to reduce noise and improve repeatability.
I hope this helps,
Ramsey
Reference
Caldas LC, Guimarães-Ferreira L, Duncan MJ, Leopoldo AS, Leopoldo APL, Lunz W. (2016). Traditional vs. Undulating Periodization in the Context of Muscular Strength and Hypertrophy: A Meta-Analysis. International Journal of Sports Science, 6(6):219-229.
