Brick Workouts: Mastering the Bike-to-Run
The single most race-specific session in triathlon. Progressions, structure and transition rehearsal for every distance.
Overview
A "brick" is a training session where you swim-bike, bike-run, or swim-bike-run back-to-back — because your legs feel like bricks when you run straight off the bike. If there's one session that separates competent triathletes from average finishers, it's this one. Your bike fitness doesn't transfer automatically to run pace off the bike. You train for that transfer directly.
This guide covers brick structure from first attempt to race-specific prep, plus transition (T2) rehearsal that saves minutes on race day. If you can ride 40km and run 5km separately, you can start doing bricks — and you should, because the gap between your open 5K time and your off-the-bike 5K time is probably larger than you think.
Golden Rule: The first 2-3km off the bike are the defining test of your triathlon fitness. Train that transition, or race-day will humble you.
Why Bricks Work
Physiologically, running off the bike challenges:
- Neuromuscular coordination — your legs have been in a cyclic range for an hour+. Running recruits fast-twitch and stabiliser muscles the bike didn't touch.
- Cardiovascular adaptation — heart rate stays elevated from the bike; the run starts you already in the upper aerobic range.
- Gait pattern — compressed bike posture shortens hip flexors and tightens quads. Your first few hundred metres running feel wooden until the body re-learns.
Bricks also train:
- Pacing — riders who race the bike hard always run poorly. Bricks teach you what effort level preserves run legs.
- Mental — the psychological transition is harder than the physical one. Practice it.
The Four Brick Types
1. Easy Brick — Shakedown
When: First 4-6 bricks of a training block. Structure: 30-45 min bike easy → 10-15 min run easy. Goal: Just get used to running off the bike. No pace target.
Do one per week until it feels normal.
2. Standard Brick — Build
When: Weeks 4-10 of a training block. Structure: 60-75 min bike at tempo → 20-30 min run at steady pace. Goal: Extend duration while managing effort. Run pace ~15-20 sec/km slower than your open pace is normal.
3. Race-Pace Brick — Specificity
When: 4-6 weeks out from race. Structure: Bike at goal-race pace for ~60% of race bike distance → run at goal-race pace for 2-5km. Goal: Rehearse the exact pace you'll try on race day. If you can't hit your goal pace in training, you won't hit it on race day.
4. Long Brick — Aerobic engine
When: Weekend peak sessions in build phase. Structure: Bike 2-4 hours steady → run 30-60 min steady. Goal: Maximum aerobic stimulus. Done at aerobic effort (70-80% HR max), not race pace.
Brick Progression by Race Distance
Sprint Triathlon (750m swim / 20km bike / 5km run)
| Phase | Typical Brick |
|---|---|
| Base | 45 min bike easy + 15 min run easy |
| Build | 60 min bike moderate + 20 min run steady |
| Race-specific | 25 km bike at race pace + 5 km run at race pace |
Weekly: 1 brick session.
Olympic (1500m / 40km / 10km)
| Phase | Typical Brick |
|---|---|
| Base | 60 min bike easy + 20 min run easy |
| Build | 90 min bike steady + 30 min run steady |
| Race-specific | 35 km bike at race pace + 8 km run at race pace |
Weekly: 1 brick session.
Half Ironman (1.9km / 90km / 21.1km)
| Phase | Typical Brick |
|---|---|
| Base | 2h bike easy + 30 min run easy |
| Build | 2.5h bike tempo + 45 min run steady |
| Race-specific | 75 km bike at race pace + 10 km run at race pace |
Weekly: 1 long brick on the weekend; 1 mid-week short brick.
Full Ironman (3.8km / 180km / 42.2km)
| Phase | Typical Brick |
|---|---|
| Base | 3-4h bike easy + 45 min run easy |
| Build | 4-5h bike + 75 min run |
| Race-specific | 120 km bike at race pace + 16 km run at race pace |
Weekly in peak: 1 very long brick Saturday; 1 mid-week tempo brick.
T2 Rehearsal — The Free Time
Transition is free time on race day. Practise it.
Setup at training: lay out your kit on the driveway as you would in transition. Park your bike there. Simulate the full T2.
The sequence (for most races):
- Stop pedalling ~50m before the dismount line
- Lift one leg over saddle while still moving (practice this at low speed on quiet roads)
- Dismount running, bike in hand
- Run bike to T2, rack
- Helmet off (unclip before anything else — rule violation otherwise)
- Running shoes on (elastic laces!)
- Hat, belt, gels grabbed
- Exit run direction
Gains from rehearsal: First-timers lose 60-90 seconds in T2. With 5-6 rehearsals, most riders get this to 30-45 seconds. Over a sprint tri, that's 2% of race time — free.
The Transition Run Cadence Trick
First 500m off the bike, deliberately run at a higher cadence than your normal running pace, using slightly shorter strides. Why:
- Breaks the cyclic bike pattern faster
- Quicker re-engagement of running muscles
- Lower impact at a time when muscles are confused
Normal: 170-180 steps/min. First 500m off bike: aim for 185-190. Strides feel short. This is correct.
After 500m, natural cadence returns.
Fuelling a Brick
Treat a brick like a race for fuelling practice:
- Pre-session: normal meal 2-3 hours before. Carb-focused.
- During bike: 40-60g carbs per hour, water with electrolytes
- Bike-to-run transition: one last carb hit as you start the run (gel or chews)
- During run: for bricks over 45 min total, 30g carbs per hour
- Post-session: 1-1.5g protein per kg bodyweight within an hour + carbs to replenish glycogen
This also tests your race-day nutrition. Nothing on race day should be new — every gel, every electrolyte drink, every food should be trained with.
Common Mistakes
- Racing the bike. You'll blow up on the run. Sit on goal bike effort; the run is the time to attack.
- Sprinting the first 500m of the run. Legs will feel shockingly heavy, then will feel good, then will get tired. Pace the first 500m based on the "good" state you'll reach at 1-2km.
- Neglecting T2 rehearsal. A session is ~2 hours. Skipping the 3 minutes of T2 practice is strange priorities.
- Dehydration. Bricks accelerate fluid loss. Under-hydration kills run pace far more than run fitness does.
Structuring a Week Around Bricks
A brick is a hard session. Fit it carefully:
| Day | Typical session |
|---|---|
| Mon | Easy recovery (swim or walk) |
| Tue | Bike intervals |
| Wed | Run intervals |
| Thu | Swim + easy run |
| Fri | Rest or recovery |
| Sat | BRICK — long session |
| Sun | Long steady swim + optional easy cycle |
Monday is NOT the day to brick — you'll be tired from the weekend. Saturday is the day most triathletes use.
What's Next
Once you're bricking comfortably through build weeks, the next step is race-specific rehearsal. For Ironman athletes, move to Full Ironman 20-Week Plan; for Half Ironman, layer this into your Half Ironman Training Plan.