Session

Nice — I remember you've kept a steady running habit (your morning runs a few times a week), so we're not starting from zero. A half-marathon is 21.1 km, and 12 weeks is plenty of runway to get there safely from a 10k base.

Here's the shape of it:

Weeks 1–4 — Build the base • 3 easy runs/week, keep them conversational • One "long" run each week, growing 10k → 11 → 12 → 13 km • Add one short strides session to keep the legs snappy

Weeks 5–8 — Add distance + a little speed • Long run climbs 14 → 15 → 16 → 17 km (every 4th week, dial it back to recover) • One tempo run: 20 min at a comfortably-hard pace

Weeks 9–11 — Peak • Longest run hits 18–19 km — you never need to run the full 21 in training • Keep the tempo work; practice race-day fueling on the long runs

Week 12 — Taper • Cut volume ~40%, stay fresh, sleep well. Race day: start slower than feels right.

Want me to turn this into a week-by-week schedule with specific distances?

Got it — I'll keep your morning-runner note in mind and put every long run on a Saturday morning. Here's the first block:

Week 1 • Tue AM — 5 km easy • Thu AM — 5 km easy + 4× strides • Sat AM — 10 km long (easy pace) • Sun — rest or gentle walk

Week 2 • Tue AM — 6 km easy • Thu AM — 5 km easy + 4× strides • Sat AM — 11 km long • Sun — rest

I've saved your preferences (mornings, weekend long runs, 10k base) so the rest of the plan stays consistent. Say "continue" and I'll lay out weeks 3–12 the same way.