First Half Marathon Training: What the Research Says

The first half marathon plans all look alike, except on one point: their length. Depending on the brand or coach, you need 8, 10, 12 or 16 weeks. Each one defends its number with confidence.

What really matters is the method: build up in steps, ease off before race day, fuel during the effort. Once that method is set, you choose a plan and adjust it to your life.

How many weeks? It depends on where you start

No length is official: the 8 to 16 week calendars come from coaches and brands. The right plan is the one you'll stick with to the end.

Here's a rule for choosing, the one coaches use:

• You already run regularly and have run a 10 km, or are close: take the short end, 8 to 10 weeks.
• You're starting from zero, or your base is irregular: take 12 to 16 weeks. A longer plan leaves more room for progress, missed weeks and surprises.

To set a realistic target time, the pace calculator turns a goal finish time into a pace per kilometer.

If you have cardiovascular risk factors (family history, smoking, age, shortness of breath when exerting yourself), talk with your doctor before committing to hard training.

Building up without getting hurt

The main risk in half marathon training is injury, especially when you're new to running.

Beginners get hurt more than twice as often as regular runners. It's safer to build up in steps than in jumps.

The 10% rule: caution versus reality

You've probably heard that you shouldn't increase your weekly mileage by more than 10%. Studies add two nuances:

• In 261 runners followed for 14 weeks of half marathon training, more injuries appeared at 21 days when weekly distance rose by 20 to 60% than when it rose by less than 20% (Damsted, 2019). The difference was no longer significant at 56 and 98 days.
• A randomized trial of 532 novices found no protective effect from a graded program following the 10% rule: 20.8% got injured versus 20.3% with a standard 8-week program (Buist, 2008).

A concrete example: going from 20 to 24 km per week is +20%. Going from 20 to 32 km is +60%. Jumps like that are the ones to avoid. As for the 10%, it isn't a proven rule: it's a practical safety margin, not a law.

A typical week: what a training block is made of

This breakdown comes from coaching practice: three or four runs, plus strength work.

An example of a four-run week: easy run on Tuesday, quality session on Thursday, rest on Friday, long run on Sunday, a second easy run on Wednesday or Saturday depending on your fatigue, and a little strength work on Monday. With three runs, just drop the second easy run.

The classic beginner mistake is running easy runs too fast. If you can't hold a conversation, slow down: there's no point shaving three seconds off each km on a Tuesday. To set your paces, the heart rate zones calculator gives you benchmarks based on your heart rate.

The final stretch: taper, fueling, registration

The taper, or how to arrive fresh

A 2007 meta-analysis of endurance athletes concludes that the most effective strategy lasts 2 weeks, with volume cut by 41 to 60% and intensity and session frequency left unchanged (Bosquet).

Sessions get shorter, not fewer. These athletes are competitors, not beginners: for a first half, keep the idea (less volume, same pace) rather than the exact figure.

Eating during the race

The joint position paper from the Academy of Nutrition and Dietetics, Dietitians of Canada and the American College of Sports Medicine (2016) gives a benchmark: 30 to 60 g of carbohydrates per hour for efforts of 1 to 2.5 hours. For 2 hours of running, that's 60 to 120 g in total. It is the reference text we have for this kind of effort, and it is North American.

Race day is not the time to try a new product: test what you plan to take during your long runs. The article on long run fueling shows you how to check that it works. For drinking, train the same way, testing during your workouts what agrees with you.

Registering in France

Since September 2024, the French Athletics Federation (FFA) no longer asks non-license holders for a medical certificate for its road and trail races: it has been replaced by the Parcours de Prévention Santé (PPS), a health questionnaire and prevention videos you complete online. A valid athletics license exempts you from this step.

PPS terms change over time (validity, price), and some races organized outside the FFA apply other rules: check athle.fr and the race organizer before you register.

What you can do before your next workout

• ✓Count the days you can really run, then choose a plan with that many sessions or one fewer.
• ✓Set the race date, then count back: 2 weeks of taper, the rest to build up gradually.
• ✓Schedule your next long run so you can test your fueling in it.
• ✓Look up the paperwork you need to register.

Using the split time calculator, you can see what a 21.1 km race looks like at different paces and set your race-day checkpoints.

For example, if your weekly distance jumps from 20 to 32 km in one week, ELYO flags it from your watch data. It reads your workouts, compares pace, heart rate, volume and consistency, then adjusts your training plan to the week you actually ran.

Written with the help of AI.