Open any rider's TrainingPeaks calendar and you'll see beautiful power files. Normalised power, intervals hit to the watt, a tidy TSS for every session. And right next to all that data, there's a small empty box — the comment field — that most riders never touch.
That empty box is, in my experience, the most undervalued field in the whole platform. The power file tells you what you did. The note you type afterwards tells you what it cost. And the gap between those two things is where the most useful information in your entire training week is hiding.
Power is half the story
A power meter is an honest instrument. It tells you, to the watt, exactly what you produced. But it tells you nothing about what producing it took out of you, and that second number matters just as much.
Picture two Tuesdays. Both times you ride the same threshold session — 2x20 at 250 watts. The power file for both is identical. But on the first Tuesday you'd slept eight hours, eaten well, and the session felt like a controlled RPE 5. On the second Tuesday you'd had three broken nights, a brutal week at work, and the same 250 watts felt like an RPE 8 — you barely held the second interval together.
The power meter says those two sessions were the same. They were not. The first was productive training. The second was you digging into reserves you didn't have. And the only record that captures the difference is the RPE you log and the note you write. Without it, your calendar quietly tells you a lie: that everything's fine, because the watts were there.
That divergence — same power, much higher perceived cost — is one of the earliest and most reliable signs that fatigue is accumulating. It shows up in how the session felt days, sometimes weeks, before it shows up as a drop in your actual power numbers. Miss it, and you train straight through the warning into a hole. Catch it, and you back off a few days and save your block.
Session RPE: the number that travels everywhere
There's a way to turn that feel into something you can track, and it's called session RPE, or sRPE. You take your overall RPE for the workout and multiply it by the duration in minutes. A two-hour ride at RPE 5 is 120 minutes × 5, so 600. A brutal hour of intervals at RPE 9 is 540. One simple number for the whole session's subjective load.
What's striking is how well this lines up with the power-based world. The published research on sRPE-derived training load shows it tracks closely with TSS for most riders. So you've got two independent measurements of how hard your training week was — one built from watts, one built from feel — and most of the time they agree. The interesting part is when they don't. When your sRPE load is running well above your power-based TSS week after week, your body is telling you the training is costing more than the numbers suggest. That's a conversation worth having with yourself, or with a coach, before it becomes a forced rest week.
And there's a bonus: sRPE works on every ride. The day your power meter battery dies, the day you ride a hire bike, the run you do in the off-season — none of those have a TSS, but all of them have an sRPE. It's the one load metric that never leaves you.
What a useful note actually looks like
You don't need to write an essay. Ten seconds is the target, because a note you'll actually write every day beats a perfect note you'll abandon in a fortnight.
A good one covers five things: your RPE, how the legs felt, your sleep the night before, any life stress, and how the fuelling went. Something like: "RPE 7, legs flat from the start, slept 6 hours, big deadline this week, under-fuelled the first hour." That single line tells you — and a coach — far more than the power file alone. It explains why the watts were down, and it flags three things (poor sleep, work stress, under-fuelling) that all point the same way.
Log it to TrainingPeaks every session and something valuable builds up over a season: a record of your own patterns, sitting right alongside the power data on the same calendar. You start to see what precedes a good block and what precedes a bad one. You notice that your best sessions follow nights over seven hours, or that your form falls apart in the third week of every work crunch. That self-knowledge is a genuine performance tool, and it lives entirely in the notes. No algorithm can hand it to you. You have to write it down.
The masters angle: your recovery is the variable
If you're the wrong side of 45, the post-session note isn't a nice-to-have. It's close to essential, and here's why.
The single biggest change in training as you age isn't the work you can do — plenty of masters riders still hit big numbers. It's how variably you recover. At 25, you bounce back from a hard session in a fairly predictable way. At 52, the same session might cost you two days one week and five the next, depending on sleep, stress, a bad night, a head cold you didn't know was coming. The recovery is the variable, and it moves around far more than it used to.
That variability is invisible in the power file and glaring in the notes. The watts you produced on Tuesday don't tell you that you're still flat from Saturday. The RPE and the one-line note do. A masters rider who logs "RPE 8 on what should've been a 5, third poor night running" has just caught, in ten seconds, the exact signal that a younger rider could afford to ignore and an older rider cannot. Train through that signal repeatedly and you don't get fitter — you get injured, ill, or stale.
So if you're a masters rider, treat the note as part of the session, not an optional extra. It's how you manage the one thing that genuinely changes with age, and it's why the riders who keep getting faster into their fifties are almost always the ones who pay attention to how the work lands, not just how much of it they did.
Why the human in the loop matters
This is the part I care about most, and it's why I keep pushing back on the idea that software can coach you on its own.
When I had the principles of the best coaches in mind — the Dan Lorangs and John Wakefields who actually run World Tour programmes — the recurring theme is that the data is an input, not the decision. The best software in the world can't replace honest feedback, because the magic is in reading between the lines. A coach who sees "easy ride, felt like an 8" on what was meant to be a recovery spin doesn't need the HRV or the power curve to know what to do. They ease the week. A coach who sees three nights of broken sleep logged before a key session moves the session. That's coaching the rider, not the plan — and it's only possible because the rider told the truth in the box.
An algorithm adjusts to the data you feed it. A coach reading your notes adjusts to you — to the work stress you mentioned, the niggle in the knee you flagged, the fact that you said the legs felt great two days before a key session. That context is what turns a number into a good decision, and the post-session note is where the context lives. It's why the riders we coach inside the Not Done Yet community log RPE and a line of feedback on every session — not because we love admin, but because that's where the coaching actually happens.
Start tomorrow
Here's the change you can make this week, and it costs you nothing but ten honest seconds a day. After every session, before you close the app, put a number on how it felt and write one line about why. RPE, legs, sleep, stress, fuel.
Do it for a month and you'll have something most riders never build: a true record of how your training is landing, not just what you produced. You'll catch the bad weeks before they catch you. You'll understand your own patterns better than any chart can show you. And if you ever do bring a coach in, you'll hand them the one thing that makes them genuinely useful — the truth about how it felt.
The watts are only half the story. Write down the other half.
For more on combining the two, RPE and power: using them together is the companion read, and the signs of fatigue and when to back off covers what to do when the notes start pointing the wrong way. If you want a coach reading yours, we're on Skool.