Key takeaways
Traditional periodisation moves from base to build to peak, mixing many qualities at once, while block periodisation concentrates one target per block
In trained cyclists, a 12-week block plan raised VO2max by 8.8% versus 3.7% for the same total hard work spread evenly
A VO2max block is short and intense, framed by easier weeks, and only makes sense once you have a solid aerobic base
Doing the same week over and over works for a while, then stalls. Periodisation is the practice of organising training into phases so that load rises, peaks and recovers in a planned order. This guide covers the classic base, build and peak model, block periodisation, deload weeks, and how to fit a dedicated VO2max block into a season.
Traditional periodisation: base, build, peak
The traditional model divides the season into progressively more specific phases:
| Phase | Typical length | Focus | Intensity mix |
|---|---|---|---|
| Base | 6–12 weeks | Aerobic volume, strength, technique | Mostly easy, strides, light tempo |
| Build | 6–10 weeks | Threshold and VO2max, race-specific work | Easy plus 2 hard sessions per week |
| Peak | 2–4 weeks | Race pace, sharpening | Slightly less volume, key race-pace sessions |
| Taper | 1–3 weeks | Shed fatigue | Volume down 41–60%, intensity kept |
| Transition | 1–4 weeks | Physical and mental recovery | Unstructured, easy |
Within each phase, most plans use mesocycles of three to five weeks: two to four weeks of rising load followed by an easier week.
Throughout, the intensity distribution stays similar. Seiler's review found that successful endurance athletes keep about 80% of sessions at low intensity and fold high-intensity work in throughout the training cycle, not just in a final sharpening phase (80/20 polarised training).
Block periodisation explained
Vladimir Issurin's 2010 review in Sports Medicine argued that the traditional model, developed some five decades earlier, has four limitations for high-level athletes:
- Conflicting responses from "mixed" training aimed at many abilities at once
- Excessive fatigue from long periods of multi-targeted training
- Too little stimulus from the medium and low concentrations of load typical of mixed training
- No way to deliver several peaks in one season
His alternative, block periodisation, sequences specialised blocks that each carry a highly concentrated load aimed at a minimal number of target abilities. Abilities are developed one after another rather than all at once. Issurin outlines a taxonomy of blocks: accumulation (basic abilities such as aerobic endurance and strength), transmutation (more specific abilities) and realisation (race preparation and taper).
Block periodisation in cyclists: the Rønnestad studies
Bent Rønnestad's group in Lillehammer tested this directly in trained cyclists, keeping the total amount of hard and easy training the same in both groups and changing only how it was distributed.
- 4-week study (2014). One group did five high-intensity interval sessions in week one, then one per week for three weeks. The other did two per week throughout. The block group improved VO2max by 4.6%, peak power by 2.1% and power at 2 mmol/L lactate by 10%; the traditional group did not change significantly.
- 12-week study (2014). Every fourth week contained five interval sessions, followed by three weeks with one. The comparison group did two per week for 12 weeks. VO2max rose 8.8% versus 3.7%, and power at 2 mmol/L lactate tended to rise more (22% vs 10%).
A 2019 meta-analysis by Mølmen, Øfsteng and Rønnestad pooled six studies and found small favourable effects of block periodisation on VO2max and maximal power. The authors caution that studies were small and of generally low methodological quality (mean PEDro score 3.7 out of 10). Block periodisation is a valid alternative, not a proven upgrade for everyone.
Deload weeks
A deload or recovery week lets fatigue clear so adaptations show up. Common practice:
- Rhythm: 3 weeks up and 1 down for most runners; 2 + 1 for masters athletes, beginners or very heavy blocks.
- Size: volume down by roughly a third to a half; keep one short, sharp session so you don't feel flat.
- Signal-based: if resting heart rate, sleep and motivation are off for several days, take the deload early (overtraining syndrome signs).
The taper before a race is essentially a longer, deeper deload; the best-supported version lasts about two weeks (tapering before a race).
How to plan a VO2max block
Adapted from the Rønnestad protocols for runners who already have six or more weeks of steady base training:
| Week | Hard sessions | Example | Rest of week |
|---|---|---|---|
| 1 (block) | 4–5 | Alternate 4 × 4 min and 5 × 3 min at 90–95% max HR | Very easy short runs only |
| 2 | 1 | 4 × 4 min | Easy volume, long run |
| 3 | 1 | 6 × 3 min | Easy volume, long run |
| 4 | 1 or deload | 5 × 4 min or strides only | Volume down ~30% |
| 5–8 | Repeat once | — | — |
Ground rules:
- Use sessions such as the Norwegian 4×4 or others from VO2max workouts. Set targets by pace or heart rate with the heart rate zone calculator.
- Expect to feel tired by the end of the block week. Fitness gains show up after the following easier weeks.
- Five interval sessions in seven days is aggressive. Recreational runners can start with a three-session block week.
- Retest with a 5 km time trial or race, and check the VO2max running calculator to see whether your estimated VO2max moved. Gains vary widely between people (VO2max trainability).
Periodisation for runners: putting it together
For a spring marathon, a simple plan might be: 10 weeks of base with strides and hills, a VO2max block in weeks 11 to 14, then a threshold and marathon-pace focus in weeks 15 to 20, followed by a three-week taper. For shorter races, the VO2max block sits closer to race day. Strength training fits best in the base phase and is maintained at low volume later (strength training for runners).
Whichever model you choose, the principles are the same: progressive overload, planned recovery and a clear target for each phase.
Frequently asked questions
What is periodization in running?
It is planning training in phases so that the load rises, peaks and drops in a deliberate order, usually base, build, peak and taper. The aim is to arrive at the key race fit and fresh rather than tired or under-trained.
What is block periodization?
A model popularised by Vladimir Issurin in which each block of a few weeks concentrates a heavy load on one or two target abilities, such as VO2max, instead of training many qualities at once. Blocks are sequenced so each one builds on the last.
How often should you take a deload week?
Most coaches use one easier week every three to five weeks, cutting volume by roughly a third to a half while keeping some intensity. Older or newer athletes often do better with a 2 plus 1 rhythm.
How do I plan a VO2max training block?
After a few weeks of base, do one week with four or five interval sessions, then two or three weeks with one interval session and plenty of easy running. Repeat once or twice, then test with a race or time trial.
Sources
- Issurin VB. New horizons for the methodology and physiology of training periodization. Sports Med, 2010. PubMed
- Rønnestad BR, Hansen J, Ellefsen S. Block periodization of high-intensity aerobic intervals provides superior training effects in trained cyclists. Scand J Med Sci Sports, 2014. PubMed
- Rønnestad BR, Ellefsen S, Nygaard H, et al. Effects of 12 weeks of block periodization on performance and performance indices in well-trained cyclists. Scand J Med Sci Sports, 2014. PubMed
- Mølmen KS, Øfsteng SJ, Rønnestad BR. Block periodization of endurance training: a systematic review and meta-analysis. Open Access J Sports Med, 2019. Full text
- Seiler S. What is best practice for training intensity and duration distribution in endurance athletes? Int J Sports Physiol Perform, 2010. PubMed
- Bosquet L, Montpetit J, Arvisais D, Mujika I. Effects of tapering on performance: a meta-analysis. Med Sci Sports Exerc, 2007. PubMed