Rule 28 · Performance Lab

Power Profiler.

Enter your best power for each duration. We fit a power–duration model to your data, compare the five systems it describes against the demands of your discipline, and prescribe the session that fixes the weakest one.

01Rider

Tell us who you are and what you race, so we can judge your numbers against the right demands.

What do you race?

Only used to pick the benchmark scale your W/kg is read against.

02Test sheet

Your best power at each duration. This is the raw material everything below is built from.

Best average power in watts, from a real effort in the last 8–12 weeks. Leave blanks — the model works with what you give it. Marked durations feed the critical power fit, so fill at least two of them.

The last cell is the durability test, and it's the single most useful number a long-course rider can give us: ride 2.5–3 hours steady, then go full gas for 20 minutes. Without it we fall back to estimating durability from your 60 minute power.

Live model

03Model

We fit a curve to your efforts. Critical power is the engine; W′ is the match you can burn above it.

04Systems vs. your discipline

Five energy systems, scored and stacked against what your racing actually asks of each one. The weakest for your discipline is your limiter.

The marker on each bar is the level that system should sit at for you, given how much your discipline leans on it. Bars are scored against riders on the same benchmark scale — the marker is scored against the rest of your own profile.

05The session that fixes it

One workout aimed squarely at your limiter, with every interval in your own watts.

06Where it goes in the week

A sensible week to hang that session on, so the hard days are hard and the easy days are easy.

07Your zones

Every training zone in watts, calculated from your critical power. Set these in your head unit.

Zone% of CPWatts

08The kit that helps most

The aero gear that buys back the most watts for how you race.

Chosen for what you race, not what you scored. Every watt of drag these save is a watt you don’t have to find in the sessions above.

Retest in 6 weeks

We'll send this profile as a PDF, plus a reminder to repeat the same test sheet in six weeks so you can see whether the block moved the number it was supposed to move.

Modelled from a two-parameter critical power fit. Estimates only — they describe what your data implies, not what your physiology guarantees. Benchmarks are approximate and read from published ranges for trained cyclists. If you're new to structured training, returning from illness or injury, or have any cardiovascular condition, talk to a coach or clinician before starting hard interval work.