If you're training for a triathlon, you've probably heard the term "brick workout" and wondered what it means and whether you need to worry about it. The short answer is yes; understanding the benefits of brick workouts for triathletes could be the difference between a run leg that falls apart and one that actually goes to plan.
I've been through race days where the bike-to-run transition felt like my legs had been replaced with concrete. I've also coached hundreds of age-group athletes through the same experience. The good news is that this is one of the most solvable problems in triathlon training, and you don't need to do anything complicated to fix it.
Why Trust Us?
ACTIVE.com's editorial team relies on the knowledge and experience of fitness and wellness experts, including competitive athletes, coaches, physical therapists, nutritionists, and certified trainers. This helps us ensure that the products we feature are of the highest standard. Collectively, the team has spent countless hours researching equipment, gear, and recovery tools to create the most accurate, authentic content for our readers. Customer satisfaction is also a key part of our review process, which is why we only feature highly rated products.
Why the Bike-to-Run Transition Breaks Athletes on Race Day
My first triathlon was a Try-A-Tri. I had spent months swimming, biking, and running. I could cover each distance on its own without much trouble. But when I hopped off the bike and tried to run, I nearly fell over. Three steps in, my quads locked up so badly that I ran the entire run leg with my knees barely bending. I had done zero brick workouts. I didn't even know they existed.
Here's what's happening in your body during that transition. On the bike, your legs are in a bent, supported position, and your body weight is supported by the saddle. The blood is pooled in your legs, your cardiovascular system is adapted to the cycling position, and your weight is distributed across the bike. The moment you stand up and start running, your body is fully upright for the first time in what feels like hours. It has to redistribute blood flow, recruit different muscle groups, and suddenly support your entire body weight, all at once.
Without practice, this hits like a wall. Your legs feel like bricks, your heart rate spikes, and the pace you planned for suddenly feels impossible. It doesn't matter how good a runner you are on fresh legs. Running off the bike is a specific skill that has to be trained.
What Is a Brick Workout?
A brick workout is simple: you do a bike workout, then immediately transition into a run with as little time in between as possible. That's it. The goal is to get your body accustomed to running after biking, so the transition no longer shocks your system.
The name comes because you're stacking workouts on top of each other, like bricks.
The Benefits of Brick Workouts for Triathletes
There are several reasons brick sessions are a cornerstone of triathlon training, and they go beyond just practicing the transition.
Benefit 1: Teaching Your Body to Reroute Blood Flow
During cycling, blood is concentrated in the legs, which are doing most of the work in a bent, compressed position. The moment you stand upright and start running, your cardiovascular system has to shift rapidly. Blood needs to flow differently, new muscle groups get recruited, and your heart has to adjust to a new demand almost instantly.
Without practice, that adjustment is clumsy and painful. With consistent brick workouts built into your triathlon training, your body learns to make the switch faster and more efficiently. What felt catastrophic in your first brick workout starts to feel almost normal. That adaptation is the whole point.
Benefit 2: Brick Workouts Are Time-Efficient
Because you're already in your kit and your gear is out, tacking a short run onto a bike ride adds meaningful training stimulus without much extra time. A 10-minute brick run delivers more training value than a standalone 10-minute easy run, because the post-bike fatigue forces your body to work harder; a fresh run simply can't replicate this effect.
This makes brick workouts one of the best return-on-time investments in triathlon training. If you're tight on time, a short bike-to-run session achieves more than two separate workouts of the same duration done on different days.
Benefit 3: They Build Race-Day Confidence
There's a psychological side to brick workouts that doesn't get talked about enough. Every time you run off the bike in training, and your legs come around, even if it takes a few minutes, you're building evidence that they'll come around on race day too.
That confidence is hard to quantify, but it's real. Walking into a triathlon after doing your brick sessions is a completely different feeling from showing up without having done them. You know what the transition feels like. You know you can handle it. That matters when you're standing at the swim start.
Benefit 4: Your Triathlon Run Pace Gets Closer to Your Standalone Race Pace
Most triathletes are significantly slower on the run in a triathlon than they are when running the same distance on fresh legs, and that gap is largely due to brick-workout fatigue.
A triathlete who has done little to no brick training might run 10 to 15 percent slower in a race than their standalone pace for the same distance. To put that in real numbers: if you can run a 5K in 25 minutes on a normal training day, showing up to a Sprint triathlon without brick work could mean a 27:30 to 29:00 run split. That's a lot of time left on the course simply because your body wasn't prepared for the transition.
Athletes who have done consistent brick work throughout their training season close that gap considerably. Instead of 10 to 15 percent slower, you're looking at 1 to 5 percent slower than your standalone pace, which, for that same 25-minute 5K runner, means a run split closer to 25:15 to 26:15. The fitness was always there; the brick workouts just taught the body how to access it after a hard bike.
How Many Brick Workouts Do You Need Before Race Day?
The number of brick workouts you need depends on your race distance. Here are the minimums I'd recommend completing before your race:
- Sprint: 6–9 brick workouts
- Olympic: 6–12 brick workouts
- Half-IRONMAN (70.3): 15–20 brick workouts
- IRONMAN: 30–40 brick workouts
These need to be spread out over the months leading up to your race. Cramming six brick sessions into the two weeks before a Sprint triathlon won't give your body enough time to adapt and won't help nearly as much as spreading them throughout your training season.
How Long Should Your Brick Run Be?
Here's where a lot of triathletes overcomplicate things. The purpose of a brick run is to teach your body to run after biking, not to build running endurance. Your long runs build endurance. Your brick run just needs to be long enough to trigger the adaptation, and that doesn't take very long at all.
Running off the bike for even ten minutes is enough to begin training that transition response. There's no need to do a full long run after every bike ride. In fact, doing so regularly will leave you too fatigued to execute your other key workouts well.
Use these distance guidelines based on your race distance:
- Sprint: 1–3 km (0.6–1.8 miles)
- Olympic: 1–4 km (0.6–2.5 miles)
- Half-IRONMAN (70.3): 2–7 km (1.2–4.3 miles)
- IRONMAN: 3–8 km (1.8–4.9 miles)
A short, well-executed brick run with good form beats a long, sloppy one every single time.
Brick Workout Pacing: Less Is More
Most triathletes go too hard during their brick runs, which works against them. For the majority of the training year, specifically during the base-building and strength-building phases, your brick run should be done at an easy pace below your aerobic heart rate ceiling. The goal is adaptation, not suffering.
As you move into the race season, you can begin adding short efforts at or near race pace within the brick run. For Sprint and Olympic-distance athletes, this might be a five- to ten-minute section at the start of the run, slightly faster than your target race pace, to simulate the excitement of coming out of transition. For 70.3 and IRONMAN athletes, I'd rather you start the brick run conservatively and build into a faster section toward the end, which trains the exact pacing discipline you'll need on race day.
Common Brick Workout Mistakes to Avoid
Most brick workout mistakes come down to either doing too much or not doing them at all. Here are the ones I see most often:
- Skipping brick workouts until close to race day. The adaptation your body needs takes weeks to develop. Six brick runs crammed into the final two weeks of training won't get you there. Start early and build the habit.
- Making the brick run too long. Running for an hour after every bike ride is overkill. It increases your risk of injury, leaves you too fatigued to train well for the rest of the week, and can engrain poor running form when your body is exhausted. Keep the run short and focused.
- Going too hard on the brick run. Brick sessions are not the place to chase pace for most of the season. Going too hard too often in brick runs eats into your recovery and leaves you flat for the workouts that actually require intensity.
- Taking too long in the transition. The whole point of a brick workout is to simulate the bike-to-run transition. If you take 15 minutes to change shoes, eat a snack, and scroll your phone before heading out for the run, you've lost most of the benefit. Move quickly.
- Calling a long ride plus a long run a brick workout. A 90-minute bike followed by a 90-minute run is not a brick workout. That's two full workouts back-to-back, and the fatigue it generates can set your training back significantly. Brick runs are meant to be short by design.
What About Swim-to-Bike Brick Workouts?
Some coaches have their athletes haul a bike and a trainer to the pool deck and ride in their swimsuits between sets. I am not one of those coaches; I don't prescribe swim-to-bike brick workouts for the athletes I work with.
Here's my thinking. The physiological challenge of the bike-to-run transition is severe because the change in blood flow is dramatic and immediate. You go from a bent, supported position on the bike to fully upright running in a matter of seconds. The swim-to-bike transition works differently. You're swimming, then you run out of the water, walk or jog through transition, and gradually ease into biking. If you keep that transition controlled and avoid surging, the adaptation your body needs is gradual enough that it handles it without specific training. That said, there is one swim-specific drill I do prescribe that's worth building into your pool sessions: the deck-up.
What Is a Deck-Up?
A deck-up is exactly what it sounds like. At the end of a swim interval, instead of resting at the wall, you pull yourself up out of the pool and jog in place for a short period before jumping back in and continuing your set. It trains your body to reroute blood flow from the horizontal swimming position to upright movement, which is exactly what happens when you exit the water on race day.
,br/> Start with 10 seconds of jogging in place and build up to 30 seconds as the drill becomes more comfortable. Here's an example of how to structure a deck-up set in a pool workout:
- At the wall, pull yourself out of the pool onto the deck
- Jog in place for 10–30 seconds
- Jump or dive back in immediately and continue
- Repeat for 6–8 rounds as one complete set
That's it. No bike on the pool deck, no Speedo aerobics. Just a simple drill that preps your body for the swim exit without adding complexity to your training week.
Wrap-Up
Brick workouts are not optional in triathlon training. They are the specific tool that teaches your body to handle the bike-to-run transition, and without them, even fit, experienced athletes can have the run leg fall apart completely. The good news is they don't need to be long, they don't need to be fast, and they don't require a huge time commitment to be effective.
What matters most is consistency. A steady diet of short brick runs spread across your training season will do far more for your race day performance than any single epic session. Keep the runs short, keep the pace honest, transition quickly, and do them regularly.
The run leg of a triathlon doesn't have to be the part of the race where everything unravels. With the right approach to brick training, it can be the leg you actually start passing people with.