Half Marathon Speed-Up Plan: 12 Weeks from Finishing to Chasing a PB

Introduction

The half marathon (21.0975 km) is one of the most popular distances in Taiwan’s road racing scene. The Taipei Marathon half marathon, Tianzhong Half Marathon, and Wanjinshi Half Marathon attract tens of thousands of runners every year. For many, “finishing” is no longer the challenge—the real question is “how to run faster and more steadily.”

The key to improving your half marathon time isn’t about running “harder,” but about improving your metabolic efficiency at race pace—making your target pace feel easier and fundamentally solving the late-race fade after the 15 km mark.

12-Week Training Structure

Half Marathon Target Pace Reference

Key Workouts: Strength Phase (Weeks 5–8)

Monday: Complete rest

Tuesday: Tempo Run strength session

• 2 km warm-up + dynamic stretching
• 30-minute Tempo Run @ LT pace (15–20 sec/km faster than half marathon goal pace)
• 2 km cool-down

Wednesday: Easy run 10–12 km

Thursday: 1000m intervals

• 2 km warm-up
• 5 × 1000m @ vVO2max (30–40 sec/km faster than half marathon goal pace)
• 2 km cool-down

Friday: Rest or 30-minute easy jog

Saturday: Long run 18–20 km

• First 15 km @ easy pace
• Last 3–5 km @ marathon pace (slightly faster than half marathon pace)

Sunday: Easy run 8–10 km

The Fundamental Solution to Half Marathon Fading

Many runners experience a sharp drop in pace after the 15–16 km mark, usually due to:

1. Starting too fast: Running 10–15 sec/km faster than target pace, depleting glycogen too early
2. Insufficient lactate threshold: Target pace exceeds LT, causing continuous lactate accumulation
3. Insufficient training volume: Weekly mileage is too low, and long runs are not long enough to train fat metabolism

Solutions:

• Run the first 2 km 10 seconds slower than target pace
• Raise your LT pace (through Tempo Run training)
• Weekly long runs should reach at least 80% of your target race distance (i.e., at least 17 km)

Practical Advice

1. Wanjinshi Half Marathon (March): Start this plan in December, using Taiwan’s cool winter weather for strength training
2. Pace run simulation (Weeks 9–11): Include a 10–14 km segment at half marathon goal pace within your long runs to familiarize your body with race-day feel
3. Fueling strategy: Practice drinking on the move during pace runs in half marathon training to ensure race-day fueling doesn’t disrupt your rhythm
4. Rest the day before: The day before the race, do only a 15–20-minute easy run plus a few strides—no intensity work

Conclusion

12 weeks is the ideal training cycle—long enough for your body to complete a full round of physiological adaptation, yet short enough to avoid monotony. Execute this plan diligently, and your next half marathon won’t just be about finishing—it will be a breakthrough in confidence, strategy, and fitness.

Related Reading

• Half Marathon 12-Week Training Plan: A Structured Design for PB Breakthroughs
• Half Marathon 12-Week Race Prep Plan: Weekly Mileage and Intensity Distribution
• Half Marathon Sub-2 Training Plan: 12 Weeks from a 6:00/km Base to Breaking 2 Hours
• Beginner Half Marathon 12-Week Training Plan: From 5 km to Finishing 21 km