Six weeks of threshold work, and the number that finally moved

I’ve been chasing the same 20-minute number since the winter of 2023. It moved four watts in two years. This spring it moved nineteen, and honestly not because I found a magic session — I just finally stopped skipping the boring ones.

The plan was embarrassingly simple. Two structured days a week, both on the trainer, both before anyone else in the house was awake. Tuesday was 4×8 at just under threshold. Thursday was longer and softer — 2×20 sitting right at the edge of comfortable, the kind of effort where you can still think about your day. Everything else was easy, outside, and unmeasured on purpose.

What actually changed

Not the watts first — the shape of the intervals. Early on, every 8-minute block started too hard and ended in a negotiation with myself. By week four I was starting them 10 watts lower and finishing them 15 higher, and the last one felt like the second one. That’s the part no test protocol tells you about, and it’s the part that made race efforts feel survivable.

The session you finish tired and repeatable beats the session you finish heroic and skip on Thursday.

Six weeks in I retested. 268 W for twenty minutes, up from 249. Weight stayed flat, sleep got about twenty minutes better on average, and the difference on the road was less about speed and more about how long I could sit in the wrong part of a group ride without panicking.

The block, if you want to steal it

• Tue — 4×8 min @ 95–100% FTP, 4 min easy between. Add one minute per block every second week.
• Thu — 2×20 min @ 88–92% FTP, 8 min easy. Cadence stays above 90 or it doesn’t count.
• Sat — 2.5–4 h outside, zone 2, no computer screen at eye level.
• Everything else — easy, or nothing. Week 4 and week 7 are half volume.

Next block is about repeatability at race pace rather than raising the ceiling, because the ceiling isn’t what’s losing me races. Being cooked by lap three is. More on that when I’ve got numbers instead of opinions.