Training for a marathon, half marathon or another big running goal takes time, consistency and patience. While your focus is naturally on crossing the finish line at your goal race, adding another event or two along the way could actually help you perform better when it matters most.
These events are known as B-races.
Whether you're chasing a PB, running your first marathon or taking on a charity challenge, a well-timed B-race can boost your confidence, improve your race strategy and make your training more enjoyable.
What is a B-race?
A B-race is a race you complete during your training block before your main goal event, often called your A-race.
Your A-race is the event you've built your training around. It's where you want to perform at your best, whether that's achieving a new PB, completing your first marathon or just reaching the finish line feeling strong.
A B-race has a different purpose. Instead of focusing purely on the result, you use it to support your training.
That might mean:
- practising your pacing
- testing your race-day nutrition
- getting used to running in a crowded race
- trying out your race kit
- building confidence ahead of your goal event.
Think of it as a dress rehearsal rather than the main performance.
Why should you run a B-race?
Break up a long training block
Marathon and half marathon training can last anywhere from 12 to 20 weeks. That's a long time to stay motivated.
A B-race gives you another milestone to look forward to and helps keep training fresh. Swapping one of your usual long runs or harder sessions for an organised event can make training feel more rewarding, especially when there's crowd support, aid stations and a finish-line medal waiting for you.
Practise your race-day routine
One of the biggest advantages of running a B-race is the chance to rehearse everything you'll do on race day.
Instead of leaving it to chance during your A-race, you can find out:
- whether your pre-race breakfast works
- if your race shoes are comfortable over longer distances
- when to take your gels
- how much fluid you need
- whether your race-day kit feels comfortable after several miles.
If you're running for charity, it's also the perfect opportunity to wear your charity vest, test any hydration pack or running belt, and make sure everything is comfortable before your main event.
Small adjustments now can prevent big problems later.
Learn to pace yourself
Many runners start races too quickly thanks to the excitement and adrenaline at the start line. A B-race gives you the opportunity to practise sticking to your target pace under real race conditions.
Whether you're aiming for an even split, negative split or marathon pace effort, you'll gain valuable experience that can make pacing feel much more natural during your A-race.
Measure your marathon or half marathon fitness
Training can sometimes feel like a leap of faith.
A B-race provides a useful checkpoint, giving you a better understanding of how your fitness is progressing.
You don't need to chase a PB’s every time. Simply comparing your effort, pacing and recovery to previous races can help you judge whether your training is moving in the right direction.
For experienced runners, shorter races such as a 5k or 10k can also help identify realistic pace targets for longer events.
Build confidence before your goal race
Every race teaches you something. You'll become more familiar with race-day logistics, standing in a start pen, navigating water stations and managing those pre-race nerves.
By the time your A-race arrives, many of the unknowns will already feel familiar, letting you to focus on enjoying the experience rather than worrying about what comes next.
How to choose the right B-race
A B-race doesn't have to be a traditional road race. Charity fun runs, colour runs, relay events and even obstacle races can all be a great way to break up a long training block while giving you valuable race-day experience. Just bear in mind that obstacle races, like Tough Mudder or Spartan Race, are often more physically demanding than a standard road race, so you'll need to leave yourself enough time to recover before your A-race.
The best B-race is one that complements your training rather than disrupting it. Here are a few examples:
|
Goal race
|
Good B-race options
|
|
Marathon
|
Half marathon, 10-mile race, 20-mile race or charity 10k
|
|
Half marathon
|
10k, 10-mile race or charity 5k
|
|
10k
|
5k (like parkrun, or TN5k for runners in the UK!) or charity fun run
|
|
5k
|
Road mile, relay race or cross-country race
|
Whichever event you choose, make sure it fits naturally into your training plan and allows enough time for recovery afterwards.
As a general guide, many marathon runners benefit from completing a B-race around three to six weeks before race day, giving them enough time to recover while still making the most of the fitness and confidence they've gained.
Should you race your B-race all out?
That depends on your training goals.
If your B-race is much shorter than your A-race, such as racing a 10k while training for a marathon, you may choose to race it hard. This can provide a valuable speed workout and give you an indication of your current fitness.
However, if your B-race is closer in distance to your goal event, it may be more beneficial to treat it as a training run.
You could:
- run sections at your goal marathon pace
- practise your fuelling strategy
- stick to your planned hydration schedule
- focus on running a controlled, consistent effort.
Remember, the priority is arriving at your A-race healthy, confident and well prepared.
B-races are great for charity runners too
If you're training for a charity place, a B-race offers benefits beyond your running.
It's an opportunity to:
- share your progress with supporters
- capture photos and videos for fundraising updates
- test your charity vest and race-day kit
- celebrate another milestone on your fundraising journey.
Supporters enjoy seeing your progress, and regular updates can help maintain momentum with your fundraising throughout your training.
Frequently asked questions
What's the difference between an A-race and a B-race?
An A-race is your primary goal event and the race you've structured your training around. A B-race is completed during your training and is used to practise race-day strategies, assess your fitness or simply gain more racing experience.
How many B-races should I run?
Most runners benefit from one or two B-races during a marathon or half marathon training block. Racing too often can make recovery more difficult and interfere with key training sessions.
Should I taper before a B-race?
A full taper usually isn't necessary. Depending on the distance and your training plan, reducing your training slightly beforehand may help you feel fresher while still maintaining your overall fitness.
Can beginners run a B-race?
Absolutely. B-races are particularly useful for first-time runners because they help you practise race-day routines, build confidence and understand what to expect before your goal event.
The bottom line
A B-race isn't there to distract you from your goal. It's there to help you reach it.
Whether you're practising your pacing, testing your nutrition, building confidence or enjoying another day on the start line, the right training race can make your race-day preparation more effective and much more enjoyable.
Choose your B-races carefully, treat them as part of your training rather than the finish line itself, and you'll give yourself the best possible chance of success when your A-race finally arrives.
