Brick Session: 80km Bike and 10km Run for 70.3 Preparation

Session Overview

This advanced brick session combines an 80km bike leg at 70.3 race intensity with an immediate 10km run to simulate the full physical demand of a half IRONMAN race. It is one of the most race-specific training sessions in long-course triathlon preparation and should be attempted only after a solid base of standalone bike and run fitness.

What You Will Need

• Road or TT bike, helmet and cycling shoes
• Running shoes and race number belt (practise your T2 swap)
• On-bike nutrition: 3-4 gels or bars, 2 x 750ml bottles
• Run nutrition: 1-2 gels for the 10km run leg
• GPS watch tracking both cycling and running data

The Bike Leg (80km)

Ride 80km at 70.3 race effort — approximately 65-75% of FTP or RPE 6-7/10. The first 20km should feel almost too easy; resist the urge to ride harder. Eat and drink on a schedule: take nutrition in the first 20 minutes and every 20-25 minutes thereafter. Practice fuelling at pace rather than waiting for stops. Target 60-80g of carbohydrate per hour throughout the bike leg.

• Bike intensity: 65-75% FTP, RPE 6-7/10
• Fuelling: every 20-25 minutes from minute 20 onwards
• Target carbohydrate: 60-80g per hour
• Hydration: 500-750ml per hour depending on conditions

T2 Simulation

Simulate a race transition: rack your bike, change shoes, clip on your race belt and begin running within 60-90 seconds. Do not sit down or take a break. This practises the physical and psychological reset required on race day, when you need to start running on tired legs with minimal hesitation.

The Run Leg (10km)

The 10km run comes immediately after the bike. Your legs will feel heavy and uncoordinated for the first 1-2km — this is completely normal and expected. Start at a pace 15-20% slower than your fresh 10km pace and let your body adapt. By km 3-4, you should find your rhythm. The back 5km is when you assess how well you paced the bike: if you feel strong, build pace; if you are suffering, the bike effort was too high.

Cool-Down (10 minutes)

Walk for 5-10 minutes after the run, then light stretching. Eat a recovery meal or shake with 20-30g protein and 60-80g carbohydrate within 30 minutes of finishing. This session is a significant training stress — factor in 48-72 hours of reduced intensity before your next quality session.

Coaching Notes

• Do this session 8-12 weeks before your target 70.3 race, not in the final taper weeks
• Common mistake: riding the bike too hard and suffering a very slow run — keep bike effort disciplined
• Scale down: 60km bike + 8km run if 80km is beyond your current fitness
• Scale up: 90km bike + 12km run for athletes targeting IRONMAN-level race simulation