Sub-4 marathon training plan

What a sub-4 marathon takes

To finish in 3:59:00 you need to average 5:40 per kilometre (9:07 per mile) for 42.195 km, and reach halfway in about 1:59:30. That pace should feel comfortable for the first hour: if it already feels like work in training, the goal is a stretch for this block.

A good check is a recent race. On the standard equivalence model (Riegel’s formula, the one Run 42 uses), a 3:59 marathon matches a 10K in about 51:57 or a half marathon in about 1:54:38. Most runners lose a little more than the formula says over the full distance, so if your half is right on 1:54:38, aim for the plan and let the last long runs tell you whether 3:59 is realistic.

Your training paces

Every pace below comes from the goal time. Easy runs are deliberately slow: they build the aerobic engine and leave you fresh for the two sessions that matter each week.

The 16-week sample plan

This is the plan Run 42 builds for a 3:59 goal, four runs a week, the long run on Sunday, for a runner who raced a half marathon recently. It starts at about 37 km a week and peaks around 60 km. Long runs are set by time, not distance, and top out at 3h00.

• Weeks 1–3, base: easy running only, so the volume can climb without strain.
• Weeks 4–6, build: one quality session a week, alternating threshold and VMA intervals.
• Weeks 7–13, peak: each week a marathon-pace run (8, then 10, then 12 km) and a threshold or VMA session; from the third week, long runs with 2×5 km at marathon pace in the second half.
• Weeks 14–15, taper: volume drops to about 60% then 40% of the peak, with a short marathon-pace rehearsal.
• Week 16, race week: three short easy runs and the race.

Every fourth week is a cutback week, about a quarter lighter, so the work can sink in.

Making sub-4 happen

• Keep easy runs easy. At 6:31–7:11 per km you should be able to talk in full sentences. Running them at marathon pace is the most common reason a sub-4 block stalls.
• Practise fuel on the long runs. At four hours you will need carbohydrate during the race. Use the long runs to find gels or drinks your stomach accepts.
• Treat the marathon-pace runs as rehearsals. Wear race shoes, eat your race breakfast, and check that 5:40 feels controlled.
• Start slower than you want to. The first 5 km at 5:45 costs you thirty seconds. The first 5 km at 5:20 can cost you twenty minutes after 30 km.

Already faster than this? Look at the sub-3:30 plan. Not quite there yet? The sub-4:30 plan follows the same structure at a gentler pace.