Brick workouts: how long to run after the bike, and why
A brick is a bike session followed straight away by a run. It is one of the most common triathlon sessions and one of the most over-done. There is no single right length. The right run depends on what the session is for. This guide separates the purposes and gives example durations you can adjust with your coach.
Open the Triathlon Pace CalculatorWhat a brick does and does not do
A brick teaches your legs and your head to run after cycling, and lets you practise transitions, fuelling and pacing under fatigue. It does not build more fitness than the same bike and run done separately. Its value is specificity, and the cost is extra fatigue, so use it with a clear aim.
Three purposes, three different bricks
Decide which of these you are doing before you start. Mixing them is how bricks turn into hard sessions that leave you tired for days.
| Purpose | Bike before | Run after | Effort |
|---|---|---|---|
| Transition practice | Any easy ride, 30–90 min | 5–15 min | Easy. Focus on the first minutes and form |
| Pace session | 1–2 h with some steady work | 20–40 min | Steady, at or near target run pace |
| Race rehearsal | Long ride with some race-effort blocks | 30–60 min for half distance | Race fuelling, gear and pacing |
These durations are examples of common coaching patterns, not rules. Your experience, race distance and weekly load change them.
How long should the run be?
- To get used to the change of muscle use, 5 to 15 minutes is often enough.
- For specific pace work, make the run long enough to settle into your target pace, then hold it for a meaningful block.
- For a half or full distance rehearsal, do the longer version only a few times in the build, not every week.
- If you are new to running after long rides, start shorter than you think you need and add time over several weeks.
How often to do bricks
Many plans use one brick every one to two weeks and keep the long rehearsal bricks for the weeks closest to specific race preparation. If time is tight, a separate run on another day can give you more running volume at lower fatigue, while a brick gives you more race specificity. Neither replaces the other.
Keep hard bricks away from your hardest run and bike days, and reduce them in the final weeks before the race so you arrive fresh.
What to practise on the run
- Leave T2 smoothly: shoes, hat, fuel and a controlled first kilometre.
- Start slower than your target pace and settle in. Legs often feel odd for the first minutes off the bike.
- Practise your race nutrition on both the bike and the run, so the plan from the nutrition planner is tested before race day.
- Notice which pace feels sustainable after riding. Use that to check the run pace in your race plan.
Use the numbers from your race plan
Your brick run should relate to your goal. Enter your planned swim, bike and run paces and transition times in the Triathlon Pace Calculator, then use the run pace and total time to set the target for the specific part of your brick. Treat the result as a plan to test, and adjust after you see how your legs respond.
If a brick leaves you struggling to hold the pace you planned for the race, that is useful information. Revisit the bike effort in your pacing plan before you change the run goal.
FAQ
How long should a brick run be?
It depends on the purpose. Transition practice can be 5 to 15 minutes, a pace session 20 to 40 minutes, and a half-distance race rehearsal 30 to 60 minutes. Adjust to your experience and the plan from your coach.
Do I need to do bricks every week?
No. Many plans include one every one to two weeks and keep longer rehearsals for specific preparation. A separate run can add running volume with less fatigue.
Why do my legs feel strange when I start running?
Your muscles are switching from cycling to running, and that is common in the first minutes. Start easy and give them time to settle.
Should I do a brick before a sprint triathlon?
Brick practice helps at any distance, but short sessions are enough for a sprint. Use them to practise T2 and the first kilometre.