How Long Should My First Brick Workout Be?

If you have heard other triathletes talk about "brick day" and felt a little nervous, take a breath. You are in exactly the right place, and by the end of this post you will know precisely how long your first one should be. Spoiler: shorter than you think.

Let me give you the short answer right up front, then we will unpack it together. Your first brick should be about a 20 to 30 minute easy bike followed by just a 5 to 10 minute easy run. That is it. If even that run feels like a lot, walking it is completely fine. Now let me explain why so little is actually exactly right.

A Quick Reminder: What Is a Brick, and Why Do We Bother?

A brick is simply a bike ride followed immediately by a run, with as little gap between them as possible. If you want the full story, I wrote a whole post on what a brick workout actually is, but here is the version you need for today.

We do bricks for one reason: running off the bike feels strange. The first time you step off your bike and start to run, your legs may feel heavy, wobbly, and oddly disconnected, like they belong to someone else. We call this "jelly legs," and it surprises almost every new triathlete. Your muscles have been pedaling in one pattern, and suddenly you are asking them to do something completely different.

The good news is that this feeling is normal, it is temporary, and you can train your body to handle it. That is the whole point of a brick. We are not chasing distance or speed. We are teaching your legs what race day will feel like, so it does not catch you off guard.

Why Your First Brick Should Be Short and Gentle

Here is the mistake I see eager beginners make: they treat their first brick like a mini race. They ride hard, then try to run a long way, then feel terrible and assume bricks are awful. They are not awful. They were just too long, too soon.

Your first brick is a practice session, not a test. You are practicing two things: the quick change from bike to run, and the feeling of running on jelly legs. Neither of those requires you to go far. You can learn both lessons in fifteen minutes of total moving time.

So keep it tiny. A short, easy bike. A short, easy run or walk. Done. You will finish feeling like you could have done more, and that is exactly how I want you to feel. Finishing with energy in the tank builds confidence and keeps you coming back.

A Sample First Brick, Start to Finish

Here is a simple breakdown you can follow this week:

• Easy bike, 20 to 30 minutes. Keep it gentle. You should be able to chat the whole time. This is not the day to push your pace.
• Quick transition, 1 to 2 minutes. Hop off, rack or lean your bike, swap into your running shoes, and get moving. Try to keep this snappy.
• Easy run or walk, 5 to 10 minutes. Start slow. Let those jelly legs settle. If running feels like too much, walk briskly instead. That still counts.
• Gentle cooldown. Walk for a few minutes, sip some water, and notice how your legs feel by the end. They probably feel a lot more normal than they did at minute one.

That is a complete first brick. Total moving time might be under forty minutes, and that is perfect.

Why You Should Transition Quickly

You may be tempted to take a long, relaxing break between the bike and the run. I understand the appeal, but try to resist it. The magic of a brick happens in that quick changeover, because that is what mimics race day.

In a real triathlon, you move through your transition area with purpose, change gear, and head straight out to run. If you take a ten minute rest in training, your legs recover and you miss the jelly-leg lesson entirely. Keep the gap short, ideally a minute or two. If you want to get more comfortable with the changeover itself, I have a guide on moving through T1 and T2 transitions that pairs perfectly with brick training.

How to Build It Up Over the Weeks

Once that first short brick feels manageable, and it will sooner than you expect, you can grow it slowly. The key word is slowly. Add just a few minutes to the run portion every week or two, and only when the previous length felt comfortable.

A gentle progression might look like this: start with a 10 minute run off the bike, then 15, then 20, over the course of several weeks. You can lengthen the bike a little too, but the run is where the jelly-leg practice lives, so give it most of your attention.

You do not need to do bricks every session, either. One brick a week is plenty for most beginners. If you are still figuring out your overall schedule, my post on how many days a week to train for a triathlon will help you fit bricks in without overdoing it.

Keep Both Parts Easy

I want to say this one more time because it matters: keep the bike easy and keep the run easy. The brick is hard enough on its own thanks to that leg-swap sensation. There is no need to add intensity on top of it. Easy effort lets you focus on the skill you are actually building, which is running calmly through that wobbly feeling until it fades.

And it will fade. Most jelly legs settle within the first three to five minutes of running. If you can stay relaxed and keep moving gently through that stretch, you will feel your normal running legs return. That moment, when your legs suddenly feel like yours again, is one of the quietly satisfying joys of this sport.

You Have Got This

Your first brick does not need to be long, fast, or impressive. It just needs to happen. Get on the bike, ride easy, hop off, and shuffle into a gentle run or walk. Notice the jelly legs, smile at them, and keep going. That is the whole game on day one.

You are building a real triathlete's skill, one short, friendly session at a time. Whenever you want more beginner guidance like this, we will be right here cheering you on at couchtotri.com. Now go enjoy your first brick. I am proud of you already.