HBF Half Marathon

A half-marathon raced flat out: 21.1 km at 3:42/km for a 1:18:03, with heart rate averaging 177 and effort sitting in the threshold-to-VO₂ band essentially the whole way. Average running power of 469 W, parked on the ~465 W running threshold for the full 78 minutes, confirms a race held at the physiological limit rather than a controlled tempo. This is the rare case where the decode is the race itself, so the per-kilometre splits are the workout, not the structure.

Pacing was disciplined. The opening kilometre went out quick at 3:23 before settling into a tight 3:40 to 3:54 band through the middle, then a 3:20 final kilometre, a genuine closing kick rather than a fade. Heart rate parked at 177 to 180 from the second kilometre and never drifted upward, which on a hard 78-minute effort is the signature of real aerobic durability. Cadence held a metronomic 91 to 92 the whole way.

The one soft patch came around 17 to 19 km, where pace eased toward 3:54 before the finish straightened out. That mid-late dip is the classic place to find time; a few seconds per km held there is worth more than any closing sprint. As a fitness marker inside the block, a 1:18 half at this heart-rate economy says the engine was sharp going into the 50 km work.