Every year the same cycle repeats. Race season ends. Athletes take a break. They spend a few weeks doing nothing, then start a long base phase of easy aerobic training. Gradually, over months, they add intensity. By the time race season comes around again, they feel like they are only just getting back to where they were the year before.
This is the traditional periodisation model, and for age-group triathletes with limited training hours, it is one of the least effective ways to structure a year of training.
Where Traditional Periodisation Came From
Classical periodisation was developed for Olympic athletes in the mid-twentieth century. The model assumes a single peak event per year and a training schedule that can be manipulated dramatically across seasons. An athlete might train 30 hours per week during base, shift the composition entirely during a build phase, and then taper down to a single peak performance.
This makes sense when you have one goal event per year and unlimited training time. The athlete can afford to spend months building a base because the sheer volume of easy work creates meaningful adaptation. When they shift to intensity, they do so on top of a massive aerobic foundation that took months to build.
Age-group triathletes do not have this luxury. Most train 8 to 12 hours per week, race multiple times per year, and cannot afford to spend three months doing nothing but easy aerobic work. The base phase produces minimal adaptation because the volume is not high enough to drive change on its own, and the fitness they built during the previous race season decays while they wait.
The Problem With Phase Shifts
When you dramatically change the composition of your training from one phase to the next, you lose the adaptations from the previous phase. Spend three months doing only easy aerobic work, and your top-end fitness disappears. Shift to a high-intensity build phase, and the aerobic adaptations start to decay because you have removed the stimulus that maintained them.
For athletes with high training volumes, this decay is manageable because the residual fitness from 25-hour weeks takes a long time to erode. For athletes training 10 hours per week, the margins are much thinner. Fitness is gained slowly and lost quickly. Every phase shift costs you something, and the time spent rebuilding what you lost is time that could have been spent building something new.
The result is the treadmill effect. Every year you build up, peak, rest, rebuild, and peak again at roughly the same level. You never get meaningfully faster because you are always recovering from the last phase shift instead of building on top of existing fitness.
A Consistent Approach
The alternative is to maintain a consistent training structure year-round. The weekly distribution stays broadly the same: a foundation of aerobic work below HRVT1, regular sessions between the two thresholds, and targeted high-intensity efforts above HRVT2. The ratios might shift slightly depending on proximity to a key race, but the fundamental structure remains stable.
This approach works because it never allows any energy system to decay significantly. Your aerobic base is maintained by the consistent volume of easy work. Your threshold fitness is maintained by the regular moderate-intensity sessions. Your top-end capacity is maintained by the weekly high-intensity efforts. Nothing is abandoned. Nothing needs to be rebuilt from scratch.
The adaptations compound. Each week builds on the last. Each month builds on the previous month. There is no resetting to zero and starting again. Over the course of a year, you accumulate far more total adaptation than an athlete who phases their training into distinct blocks.
What Changes Between Seasons
This does not mean every week is identical. There are still variations. Recovery weeks are important. Volume might increase slightly as an event approaches and decrease afterward. The balance between disciplines might shift based on which event is next. But the overall training philosophy does not change. You are always training all three energy systems. You are always maintaining the full spectrum of fitness.
The off-season is simply a period where the pressure of race deadlines is removed. You can experiment with technique work. You can address weaknesses without worrying about tapering for an event. You can test new approaches. But you do not stop doing intensity. You do not spend months at zone one. You do not dismantle the fitness you built during the season.
Recovery Without Regression
Athletes need mental and physical breaks. That is not in question. After a race block, a recovery week or two of reduced volume and intensity is essential. But a recovery week is not the same as a three-month base phase. You can recover from a season in two weeks. You do not need three months.
The most productive approach is to take a genuine recovery period of one to two weeks after your final key race, then resume your normal training structure at slightly reduced volume. Within a few weeks, you are back to full training, maintaining all the fitness you built, and continuing to progress.
Compare this to the traditional approach where an athlete takes a month off, spends two months rebuilding their aerobic base, and then starts adding intensity. By the time they are back to their previous level of fitness, four to five months have passed. That is nearly half the year spent getting back to where they already were.
Compounding Gains Year Over Year
The real power of a consistent approach shows up over multiple years. When you never reset, each year starts from a higher baseline than the last. Your thresholds shift upward over time because they are never allowed to decay. Your aerobic engine gets bigger. Your ceiling gets higher. The improvements are incremental, but they compound.
Athletes who follow a consistent year-round approach for two to three years typically see far greater total improvement than those who follow traditional periodisation. The secret is not any particular session or workout. It is the absence of wasted months spent rebuilding lost fitness. This is one of the core training principles that guides everything in my coaching.
The fastest way to get slower is to stop training the way that made you fast. Keep the structure. Adjust the volume. Never start from scratch.