Hello, I signed up for the Barcelona marathon that's taking place in March 14, 2027. I've been running on and off for the past 2 years, but not consistent at all. My longest run was a 10.5km in 1h 14m earlier this year.

Since I didn't know where to start with training, I gave Claude my running data, told it my goal is a sub 4, and asked it for a training plan from now until the race day. This is what It came up with, I'm really curious to get some feedback. I also go to the gym 3 times a week, so it included some gym related advice too.

Phase 1 — Base

May 15 – August 31 (~15 weeks)

Session	Details	Progression
Tue — Easy	Zone 2, HR 120–145, conversational pace	40 min → 55 min
Thu — Easy	Zone 2, HR 120–145	45 min → 60 min
Sat — Long run	Zone 2, HR 120–145	See below
Gym	Full sessions, prioritise glutes and posterior chain	3×/week

Saturday long run progression:

Weeks	Duration	Approx Distance
1–4	60–70 min	~7–8 km
5–8	75–85 min	~8–10 km
9–12	90–100 min	~10–12 km
13–15	100–110 min	~11–13 km

Rules:

• Every run at fully conversational pace — if you can't hold a sentence, slow down
• Deload every 4th week: cut run volume by 30%, gym stays normal
• No quality work until Phase 2
• Knee prehab every gym warm-up: clamshells, lateral band walks, single-leg glute bridges — 2×15 each side

Target by Aug 31: 110 min long run with no knee pain, pace at same HR visibly faster than today

Phase 2 — Development

September 1 – November 30 (~13 weeks)

Session	Details	Progression
Tue — Easy + Strides	50 min Zone 2, then 4×20 sec accelerations at 85% effort, 60 sec walk between	Builds to 6×20 sec by Nov
Thu — Tempo	5–7 min warm-up + sustained effort at HR 145–165 + 5 min cool-down	25 min → 40 min tempo portion
Sat — Long run	Zone 2, final 10–15% at marathon pace from October onward	See below
Gym	Heavier compound lifts, reduce total volume, shorter sessions	3×/week

Saturday long run progression:

Month	Distance
September	12–15 km
October	17–21 km
November	22–26 km

Notes:

• Strides give the neuromuscular benefit of speed work without targeting the wrong energy system for marathon
• Tempo HR ceiling is 165 — hard but controlled, short sentences not gasping
• Deload every 4th week

Target by Nov 30: 26 km long run, tempo sustained at 6:00–6:10/km

Phase 3 — Marathon-Specific

December 1 – February 14 (~10 weeks)

Session	Details	Progression
Tue — Intervals	10 min warm-up + 6×800m at hard effort (~5:20–5:30/km), 90 sec jog recovery	Builds to 8×800m or 4×1.5 km
Thu — Easy	Zone 2, 50–60 min, full recovery	Stays easy throughout
Sat — Long run	Peaks at 30–32 km, final 5–8 km at marathon pace (5:41/km)	26 km → 32 km → back down
Gym	Maintenance only	2×/week (Mon + Fri)

Notes:

• Wednesday becomes rest or easy walk as running load peaks
• One or two peak long runs of 30–32 km in January, then begin stepping back
• 800m intervals replace sprint sessions — same VO2 max stimulus, correct energy system for marathon

Target by Feb 14: 32 km completed, comfortable at 5:45–5:50/km over 20+ km

Phase 4 — Taper

February 15 – Race Day (~3 weeks)

Week	Run Volume	Gym
Feb 15–21	–40%	1×, light
Feb 22–28	–60%, one short race-pace session	1×, very light
Race week	–70%, easy shakeouts only	Nothing