BLUF (Bottom Line Up Front)
This scoping review compared the long-term effects of Polarized Training (POL) with other Training Intensity Distribution (TID) models—Pyramidal (PYR), Threshold (THR), and Block Training (BT)—on endurance performance and physiological adaptations. In endurance athletes ranging from trained to world-class (Tiers 2–5), POL and PYR models were generally more effective than THR and BT in improving VO₂max, aerobic threshold performance, and time-trial outcomes—especially in elite and world-class athletes. All models improved anaerobic threshold performance, while differences in movement economy and overall endurance performance were less conclusive due to testing variability. In lower-level athletes, performance improvements occurred across all TID models with minimal differences.
Purpose of the Study
This scoping review aimed to:
- Analyze the long-term effects of Polarized Training (POL) on endurance-related physiological and performance variables.
- Compare POL with other TID models—Pyramidal (PYR), Threshold (THR), and Block Training (BT)—using data from controlled interventions.
- Apply the Polarization Index (PI) and McKay’s 6-tier Athlete Classification Framework to interpret differences across performance levels.
Definitions of Training Intensity Distribution Models
TID models categorize training volume across three zones, based on the traditional triphasic model, using ventilatory or lactate thresholds:
- Zone 1 (Z1): Low-intensity (below the aerobic threshold)
- Zone 2 (Z2): Moderate-intensity (between aerobic and anaerobic thresholds)
- Zone 3 (Z3): High-intensity (above the anaerobic threshold)
Polarized Training (POL)
~75–80% in Z1, ~5% in Z2, ~15–20% in Z3
Emphasis: Z1 > Z3 > Z2
Characterized by very high volumes of low intensity, minimal time in moderate intensity, and regular exposure to high-intensity intervals.
Pyramidal Training (PYR)
~70% in Z1, ~20% in Z2, ~10% in Z3
Emphasis: Z1 > Z2 > Z3
Resembles traditional endurance training with gradually decreasing volume at increasing intensities.
Threshold Training (THR)
~45–50% in Z1, ~45–50% in Z2, ~5–10% in Z3
Emphasis: Z1 ≈ Z2 > Z3
Focused on sustained work in the moderate-to-high lactate accumulation zone.
Block Training (BT)
Alternating periods of LIT and HIT in concentrated “blocks.”
Designed to overload specific systems sequentially rather than balance all zones concurrently.
Subjects
- 15 studies; 412 endurance athletes
- Participant tiers: Tier 2 (trained/developmental) to Tier 5 (world-class)
- Sports included: running, cycling, triathlon, swimming, rowing, speed skating, and mixed endurance
Athlete Tier Classification Reference
| Tier | Label | Description |
|---|---|---|
| 0 | Sedentary | No structured training |
| 1 | Recreationally Active | Casual participation |
| 2 | Trained / Developmental | Structured training; local/regional competition |
| 3 | Highly Trained / National | National-level competitors with structured, high-volume training |
| 4 | Elite / International | International-level elite competitors |
| 5 | World-Class | Olympic or top global competitors |
Findings
VO₂max / VO₂peak
- POL and PYR generally produced the greatest improvements in Tier 3+ athletes after ≥12 weeks.
- Shorter interventions or studies involving Tier 2 or Tier 4 athletes reported smaller or no changes.
- No statistically significant differences between POL and PYR in several studies.
Aerobic Threshold Performance (VT1 / LT1)
- Most Tier 2–3 studies showed positive outcomes with POL and PYR.
- PYR–POL sequences appeared especially effective.
- Elite rowers (Tier 4) and trained triathletes (Tier 2) saw no improvements in some studies.
Anaerobic Threshold Performance (VT2 / LT2)
- All TID models showed positive effects, but no single model was clearly superior.
- Effects were more consistent in Tier 2–3 athletes with 8–26% of volume in Z3.
Economy of Movement
- Two studies found improvements with both POL and THR.
- No model was consistently superior; data is limited.
Time-Trial and Competition Performance
- All TID models improved performance.
- POL and PYR were more effective in elite/world-class athletes (Tiers 4–5).
- No consistent performance differences in Tier 2–3 athletes.
- Z3 exposure (≥6%) appears important for gains, though more is not necessarily better.
Analysis of Results
- POL and PYR are optimal for VO₂max, aerobic threshold, and endurance performance in elite athletes.
- Anaerobic threshold responds well to multiple models, including THR.
- In lower-tier athletes (Tiers 2–3), all TIDs performed similarly.
- Testing protocols were highly variable; standardized methods would improve comparability.
- High Z1 volume (68–93%) and moderate Z3 exposure (6–26%) were common features in successful POL programs.
Conclusion
Polarized and pyramidal training models are the most effective for improving VO₂max, aerobic threshold, and endurance performance in elite and world-class endurance athletes. In trained and developmental athletes, all TID models—including THR and BT—can be effective. Z1 volume and Z3 intensity are key drivers of improvement. Coaches should tailor TID structures to athlete level and competition demands. Future studies should adopt standardized testing and consider using a refined 5-zone model to better capture training distinctions and outcomes.
Bibliography
Rivera-Köfler, T., Varela-Sanz, A., Padrón-Cabo, A., Giráldez-García, M.A., & Muñoz-Pérez, I. (2025). Effects of Polarized Training vs. Other Training Intensity Distribution Models on Physiological Variables and Endurance Performance in Different-Level Endurance Athletes: A Scoping Review. Journal of Strength and Conditioning Research, 39(3), 373–385.