A 16-week plan for a first 50K.

Use this if the long run is already a habit

This 16-week plan is for a first 50K when you are already running at least three days a week and can finish a comfortable long run of about 75 to 90 minutes. It is not a plan for someone new to running, returning from injury, or managing a health condition alone.

Awaiting publisher review. This is a general schedule from Running for Good Ultra, not a personal programme and not an independent coaching or medical review. The NHS says to speak to a GP first if you have not exercised for some time or you have medical concerns.

The instruction is time. The distance column shows what that time covers at 8 km/h, about 7 minutes 30 seconds per kilometre, or about 12 minutes per mile, on flat ground. Hills and walking make the distance shorter. Do not stay out until the distance is done if the time is already up.

• NHS: physical activity guidelines for adults aged 19 to 64
• If you are still choosing the race, start there
• Turn the course into a preparation brief

Four running days, and one of them matters most

Each week has a long run and three easier runs. Keep the easy runs at a talkable effort: you can speak in sentences. One of those runs, in the weeks marked hills, starts with about 10 minutes easy, then 4 to 6 short ups of about 20 to 30 seconds, walking down between them, then easy running to finish. Skip the hills on an easier week.

Leave at least one day without running between the long run and the next hard effort. Walking, and the strength work you already do, can sit on the other days. The NHS recommends muscle-strengthening activity on at least two days a week. This plan does not add a new heavy strength programme. Keep a routine you already recover from, and do not start one in the same month as the first long-run build.

A 12-week version is weeks 5 to 16. Use it only if a 2-hour long run is already comfortable. You still keep the easier week at week 8 and week 12.

The 16 weeks

Put your race on week 16. If the long run falls on the day you can protect, keep it there. The other three runs can move, as long as they stay easy and the long run is not the day after hills.

When the week does not go to plan

If you miss the long run, repeat that week once. Do not jump to the next long run to “catch up”. If you miss two long runs, or a week of illness, choose a later race rather than compressing the peak into the fortnight before the start.

Stop and get medical care for chest pain, dizziness, fainting, or pain that changes how you move. Ordinary tiredness after a long run is a reason to keep the next day easy. Pain that gets worse as you go is a reason to stop the session. This schedule cannot tell those apart for you.

• A 50-mile plan, if that is actually the race
• Plan the checkpoint times for the race you entered
• Practise the food, not just the distance