Tempo Brick Session: 60-Minute Bike at 70.3 Pace + 20-Minute Run

Session Overview

This brick session simulates the physiological demands of a 70.3 bike-to-run transition. The 60-minute bike at 70.3 race pace trains your body to sustain threshold-adjacent output for the duration of a half-iron bike leg, while the 20-minute run immediately after trains the neuromuscular adaptation required to run efficiently off a hard bike. This is one of the most race-specific sessions you can do in your 70.3 build.

What You’ll Need

• Road bike or TT bike with power meter (preferred) or heart rate monitor
• Running shoes laid out for instant T2
• Nutrition: 2 gels on the bike, water/electrolyte drink
• Quiet outdoor roads — no heavy traffic on the bike leg

Warm-Up

• 15-minute easy spin — RPE 3–4 out of 10
• 3×1-minute build efforts to 70.3 effort with 2 minutes easy between
• Return to easy spinning before the main set begins

Main Set

Bike: 60 minutes at 70.3 race intensity

• Power target: 75–80% FTP (if using a power meter)
• Heart rate: high Zone 3 to low Zone 4 — approx 80–87% of max heart rate
• RPE: 6–7 out of 10 — comfortably hard, sustainable, but not conversational
• Fuel at 20 and 40 minutes — gel + water or electrolyte drink
• Maintain aero position as much as possible — this is race simulation

T2: fast transition (target under 90 seconds)

Run: 20 minutes at 70.3 target run pace

• First 5 minutes: resist the urge to slow down — the brick feeling will pass
• Target pace: your 70.3 half-marathon goal pace or RPE 7 out of 10
• Focus on cadence and relaxing your upper body rather than chasing speed in the first minutes
• Final 5 minutes: slight pickup if legs have recovered

Cool-Down

• 5–10 minute easy jog or walk to return heart rate to baseline
• Hip flexor and quad stretches — priority after combined bike and run

Coaching Notes

The key adaptation from brick sessions happens with consistent repetition — aim to include this session once every 10–14 days in your 70.3 build. The brick feeling (heavy, heavy legs at the start of the run) diminishes noticeably after 4–6 sessions. Track your run split time over successive sessions — improvement is a reliable indicator of improving bike-to-run fitness. Take a gel in transition rather than waiting until you’re on the run.