Half-Marathon Sub-1:45 Training: Speed-Breakthrough Strategies for Intermediate Runners

Introduction

Running a half marathon under 1:45 means maintaining an average pace of 4:59/km or faster for the entire distance, leaving almost no room to ease up. Going from 2:00 to 1:45 may seem like just a 15-minute difference on the surface, but it actually represents a qualitative shift from “aerobic-dominant” to “aerobic and lactate threshold equally important.” This goal requires targeted speed work, not just increasing mileage.

Prerequisite Fitness Assessment

Before starting sub-1:45 training, evaluate yourself first:

If you haven’t met the above standards yet, focus on building your base mileage first rather than rushing into speed workouts.

Three Key Training Pillars

1. Lactate Threshold Training

The core challenge of breaking 1:45 is sustaining pace near the lactate threshold for an extended period. The target pace for Threshold training is approximately 4:45–4:55/km (5–10 seconds faster than your goal pace).

Weekly workout design:

• Wednesday: 2 km warm-up → 8 km Threshold (4:48/km) → 2 km cool-down
• Add 1 km every 2 weeks, eventually reaching a 10 km Threshold segment

2. Interval Training (Speed Reserve)

Speed needs to be built with training faster than race pace. Recommended workouts:

• 800m Repeats: 8 × 800m, target pace 4:15–4:20/km, 2-minute rest
• 1200m Repeats: 5 × 1200m, target pace 4:25–4:30/km, 2.5-minute rest

Alternate these weekly to avoid doing the same workout two weeks in a row.

3. Quality Long Runs

For intermediate runners, the long run is no longer just “easy running.” A “progressive long run” is recommended:

• First 10 km: Easy pace (5:30–5:45/km)
• Last 8–10 km: Switch to goal pace (4:55–5:00/km)

This workout simulates the fatigue of the latter half of a half marathon, training your ability to maintain pace while tired.

Sample Weekly Training Structure (Week 8)

• Monday: Easy run 8 km
• Tuesday: 800m intervals × 8 reps
• Wednesday: Rest
• Thursday: Threshold Run 10 km (14 km total including warm-up and cool-down)
• Friday: Easy run 6 km
• Saturday: Rest
• Sunday: Progressive long run 20 km

Practical Tips

• Heart Rate Monitoring: During Threshold training, heart rate should stay at 82–88% of max heart rate; going higher means the intensity is too high
• Fueling Practice: Practice using energy gels during long runs and Tempo workouts to find a brand your stomach can tolerate
• Taper 3 Weeks Before Race: Cut mileage to 60–70% of normal in the final 3 weeks to ensure you arrive at the start line in peak condition
• Temperature Effects: For every 1°C rise above the 15°C baseline, expect your pace to slow by 4–6 seconds/km

Conclusion

Breaking 1:45 is a goal that tests patience and discipline. It’s normal to experience periods of slow progress during training—speed gains often appear suddenly after an adaptation phase. Consistency in training matters more than any single workout plan.

Related Reading

• Half Marathon Sub-1:45: A 16-Week Build of Threshold and Race Pace
• Half Marathon Sub-1:45 Training Plan: A Dual-Track Approach to Speed and Lactate Tolerance
• Half Marathon Sub-1:45: Lactate Threshold Training for Advanced Runners
• Half Marathon Sub-1:30 Training: High-Intensity Workouts for Elite Amateur Runners