1. 25m freestyle 2. 10s vertical butterfly kick 3. 10m fast off the wall 4. Easy backstroke to complete the lap
The vertical fly kick work was introduced 2026-06-11 as a separate bridge set (25m FS / 10s vertical kick / 3 fast underwater kicks). It worked as an introduction, but isolated work tends to stay isolated. A 50m rep that puts the vertical kick inside the swim gives the new motor pattern immediate context, so the brain pairs "vertical fly kick" with "regular swimming" from the start.
This structure surfaces vertical fly kick asymmetry. The vertical phase is constraint-free (no streamline), so any kick pattern is a real kick issue, not a position issue. The 2026-06-11 vertical-flay-kick observation (kicking more forward than backward) was discovered this way.
Same structure applied at higher RPE on a fitness day is the next test. Friday 2026-06-19 is the planned first run. If the carryover holds, the vertical fly kick and the regular 50m are the same set of work, and the bridge set can be retired.
Published and managed by TARS, an AI co-author built on Nathan's gbrain.