Why Bricks Matter (More Than You Think)

Like many triathletes, I came into the sport with running as my strongest discipline. I had a solid resume from my years as a professional runner and, as a result, may have been a little overconfident in my expectations for the run when I signed up for my first triathlon. And by “a little overconfident,” I mean I thought I was going to win the race in triumphant fashion, passing everyone on the run on my way to eternal triathlon glory.

Then I actually started training for my first triathlon.

Tell any triathlete you’re training for a race and one of the first questions you’ll get is about bricks. “Have you done a brick?” “How are your bricks going?” “How big are your bricks?” Brick this, brick that, brick, brick, brick.

At first, I couldn’t quite understand what the big deal was. Then I did a brick, and the importance of bricks hits me…and I’m sorry for this – like a tonne of bricks.

Understanding the Brick

Let’s back up quickly, what is a brick? A brick is a training session that covers two of the disciplines of the race in quick succession. For the sake of this piece I am going to focus on the bike-run brick because it is the most crucial and common training session.

Why are bricks important? There are many benefits. First off – and I can tell you this from alarming personal experience – running off the bike is a VERY different experience than just going for a straight run.

That may seem obvious, but until you do it you just don’t know how strange of a sensation it is to go from riding for a prolonged period straight into a run. I always kind of assumed that the run portion of a 70.3 would feel like the second half of a standard marathon. I thought my legs would be tired, but I would have no problem pushing through like I had done over so many of my marathons.

My first brick session proved that theory to be false.

I remember my first one like it was yesterday, and not necessarily for a good reason. It was a simple session: I went out for an easy 60-minute Z2 ride, before switching into my trainers and getting right into a run.

I’m not lying when I tell you that I was shocked with how weird my legs felt. I was genuinely not prepared for just how odd it felt. My legs felt like jelly, I felt uncoordinated and my heart rate immediately spiked. It was terrible. Running off the bike is just…different.

It makes complete sense though. Riding and running both use the legs differently so when you go from one to the other there is a transition phase where your nervous system and muscles have to switch from the firing patterns and muscular engagement of riding to those of running. It is not just a continuation of fatigue; it’s a full switch, and without practice, it can feel very odd and unpleasant.

Fortunately, it doesn’t always have to be such a funky experience. This is where the power of the brick comes in. Much like swim technique, aero position on the bike, or smooth strides during the run, practice makes perfect. If you practice enough and prime your body to make the transition from bike to run as smooth as possible, you can truly unlock your potential and speed on the run.

Sample Sessions

To optimize your training, brick sessions are a must – but they don’t always have to be big, epic workouts, especially if you’re new to them. With bricks, consistency and frequency matter more than intensity or volume.

Starter Sessions

If you’re just dipping your toes in for the first time, I would suggest starting small. You could do what I did: a 30–60-minute ride, quick transition, then a 15–20-minute run. Short, simple, and efficient. Do one or two of these sessions each week until you feel comfortable with both the process and the sensation of running off the bike.

Repeating this transition regularly allows you to adapt both physically and mentally, building confidence in that crucial bike-to-run shift.

Larger Bricks

Once you are a seasoned brick-layer, you can really lean in and test yourself with some bigger ones ahead of race day.

One of my favourite sessions is a longer ride of 1.5-2.5 hours, finishing with race-pace efforts, followed by an 8-10km run. I’ll build into goal pace over the first half, settle into tempo for a few kilometres, then cool down.

This is a much more demanding session – it would be a key workout that you would do only a couple times during a build. And the benefits go beyond fitness. For example, these sessions are invaluable for dialing in pacing.

I’ve had workouts where I thought I could hold 300 watts on the bike, only to find my legs completely fried on the run. Backing off to 280 watts made the run far more manageable. The same applies to run pace. A 4:00/km might look possible on paper but backing off to 4:05/km might prove far more attainable after a long ride.

Bricks are also an opportunity to practice transitions, refine your fuelling, and build confidence that you’re prepared for all elements of the race.

In sum, bricks have gone from an unknown to an absolute non-negotiable in my training. My advice: lean in and stack some bricks – you’ll be happy you did!

Rob Watson is a former professional runner and a current triathlete focused on the 70.3 distance. He is also the Head Coach of Mile2Marathon Vancouver: visit www.mile2marathon.com for more information.