Building a Triathlon Training Plan

A training plan is not a list of sessions. It is the answer to one question: how do I get from the shape I am in today to the shape I need on race day — without getting ill, injured or burnt out along the way? Everything else follows from that.

This guide describes how a plan is built. The numbers in it are the same ones Tri-Train's plan generator works with.

Plan backwards, not forwards

The first entry in a plan is not the first session. It is the race. Everything is counted back from there, because that is the only way the final weeks end up in the right place.

Three things are settled before the first session:

• The target race and its date. Without a date there is no periodisation, only a pile of weeks.
• The distance. A sprint asks for something different than a full distance — not just more, but different.
• The hours actually available each week. Honestly, not optimistically. A plan that assumes eight hours and gets six stops being a plan after three weeks.

The three phases

Classic linear periodisation splits the build into three blocks, followed by the taper.

Base. High volume at low intensity. The goal is the aerobic foundation: capillarisation, fat metabolism, tendons and ligaments adapting to the load. The temptation to train hard here is strong and expensive later. This is the longest block.

Build. Volume stays high and intensity arrives — threshold work, longer intervals, the first race-specific sessions. Most of your performance is made here.

Peak. Volume drops slightly while intensity becomes specific: race pace and race demands get rehearsed, including brick sessions and fuelling.

Taper. The final one to four weeks, depending on distance. More on that below — it is the section where most goes wrong.

The shape of a week

Within a week one rule applies, and it is harder than it sounds: a hard session is followed by an easy one. Not a moderate one. Adaptation does not happen during the work, it happens in the recovery afterwards.

As a rough guide to distribution:

• About a third of sessions may be hard, the rest are easy. Six sessions a week means two hard ones — not four.
• The long session belongs on the weekend, where the time exists, and it is the most important session of the week.
• Each discipline at least twice. Swimming once a week does not maintain technique, it only slows its decline.
• Easy means easy. The most common mistake in amateur training is the moderate middle: too fast for base work, too slow to be a stimulus. It costs recovery and returns little.

How fast you may progress

Volume does not grow arbitrarily. The familiar ten-percent-per-week rule is usable but imprecise, because it ignores the starting point: going from four to 4.4 hours is not the same as going from fifteen to 16.5.

A better handle is the ramp rate — how much chronic training load (CTL) grows per week. As a guide, an increase of roughly 3 to 5 CTL points per week suits well-trained athletes; beginners should stay below that. What CTL is and how it is calculated is covered in the training load guide.

Above all of this sits a second ceiling: the time that actually exists. A plan that works on paper but not in a calendar does not work.

The recovery week

Every three to four weeks comes a week at reduced volume — around 80 percent of the preceding work week, with intensity kept intact. Experienced athletes with high load tolerance can stretch the rhythm; seven weeks is the far end and assumes disciplined recovery management.

The recovery week is not a concession to weakness. It is the part where adaptation happens. Skip it and you train more while getting slower.

The taper

In the final weeks volume drops sharply while intensity and session frequency stay. That is the decisive point: less and shorter, but not slower and not less often. Spend race week strolling and you will arrive fresh and flat.

Guideline weekly volumes, measured against your previous peak week:

• Sprint: two weeks — 70 percent, then 50 percent in race week.
• Olympic distance: two weeks — 75 percent, then 55 percent.
• Middle distance (70.3): three weeks — 80, 65, then 45 percent.
• Long distance (Ironman): four weeks — 85, 70, 50, then 30 percent.

What the plan does not know

A plan is a hypothesis about the coming weeks, not a prediction. Illness, work, poor sleep and weather get in the way, and that is normal.

So every plan comes with a willingness to change it. Two points help with that decision:

• A missed session is not made up. It is gone. Hanging it onto the next day shifts your recovery and compromises the session after it.
• Three bad days in a row are a signal, not a weakness. Elevated resting heart rate, low HRV, poor sleep, heavy legs — that is the moment for an extra easy week, not for more discipline.

Further reading

• Understanding training load: TSS, CTL, ATL and TSB
• Setting your training zones
• Tapering before a race