The beginning

The race-day clock in my local park is etched in my memory: 2:20:00, for the half-marathon. “Can I really do that?” The question scared and thrilled me in equal measure, that mix of doubt and ambition every runner knows. I tied my laces, took a breath, and decided right then to turn the question into a training plan.

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The goal

Target: 21.0975 km (half marathon) in 2 hours 20 minutes.

That works out to about 6:40 per kilometer (or 10:45 per mile). To run that pace steadily across the full distance you need three things: enough speed to hold or beat goal pace in shorter segments, a long-run base that comfortably exceeds the race distance, and the head to keep your pacing steady when things get hard.

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Pre-requisites

Before starting, you should meet at least one of these:

• Current half-marathon PB of 2:35 to 2:40 (or faster).
• Recent 10 km time of 55 min to 1 hour (or faster).
• Weekly mileage of 20 to 30 km (12 to 18 mi) over 4 to 5 days, with a long run of at least 12 km (7.5 mi).

If you’re still building base, spend 2 to 4 weeks on easier mileage first.

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How the plan works

Workout type	Purpose	Typical pace / effort
Easy run	Build aerobic foundation, support recovery	7:30–8:30 min/km (easy conversation pace)
Tempo run	Raise lactate threshold (pace you can hold for about 20 min)	6:45–7:00 min/km (comfortably hard)
Interval	Develop speed and running economy	Short bursts (400 m–1 km) at 5:50–6:10 min/km with equal jog recovery
Long run	Increase endurance, train fat metabolism	7:30–8:00 min/km (slow, steady)
Cross-train	Reduce impact while keeping fitness	Light cycling, swimming, or elliptical, 30 to 45 min easy
Rest / recovery	Allow adaptation, prevent injury	No running. Optional gentle mobility work.

Pacing note: go by perceived effort or heart-rate zone. “Moderately hard” for tempos, “hard but controllable” for intervals. Adjust if your course is flat or hilly.

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Weekly plan (10 weeks)

Week	Mon	Tue	Wed	Thu	Fri	Sat	Sun
1	Rest	Easy 5 km	Tempo 5 km (incl. 3 km @ goal pace)	Easy 5 km	Cross-train 30 min	Long 10 km	Rest
2	Rest	Easy 6 km	Intervals 6×400 m @ 5:50 min/km, 400 m jog	Easy 5 km	Cross-train 30 min	Long 12 km	Rest
3	Rest	Easy 6 km	Tempo 6 km (4 km @ goal pace)	Easy 5 km	Cross-train 30 min	Long 14 km	Rest
4	Rest	Easy 6 km	Intervals 5×800 m @ 6:00 min/km, 400 m jog	Easy 5 km	Cross-train 30 min	Long 16 km	Rest
5	Rest	Easy 7 km	Tempo 7 km (5 km @ goal pace)	Easy 5 km	Cross-train 30 min	Long 18 km	Rest
6	Rest	Easy 7 km	Intervals 4×1 km @ 6:10 min/km, 500 m jog	Easy 5 km	Cross-train 30 min	Long 20 km	Rest
7	Rest	Easy 7 km	Tempo 8 km (6 km @ goal pace)	Easy 5 km	Cross-train 30 min	Long 18 km	Rest
8	Rest	Easy 6 km	Intervals 6×400 m faster (5:30 min/km)	Easy 5 km	Cross-train 30 min	Long 16 km	Rest
9	Rest	Easy 5 km	Tempo 6 km (4 km @ goal pace)	Easy 5 km	Cross-train 30 min	Long 12 km	Rest
10	Rest	Easy 5 km	Race-pace rehearsal 8 km (last 5 km @ goal pace)	Easy 4 km	Rest	Race day 21.1 km	Celebrate

All distances are approximate. Listen to your body and adjust as needed.

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Detailed workout descriptions

Easy run

• Start with 5 min easy jogging.
• Run at a pace where you can chat normally.
• Finish with 5 min easy jogging and light stretching.

Tempo run

1. Warm up 10 min easy.
2. Shift into comfortably hard. You manage a few words, not a full conversation.
3. Include a segment at 6:40 min/km (your race goal). For a 5 km session: 2 km warm-up, 3 km at goal pace, 2 km cool-down.
4. Finish with 10 min easy running.

Interval session

• Warm up 10 min easy plus dynamic drills.
• Run the repeats (e.g. 6×400 m). Target pace each rep, then jog or walk for the same time to recover.
• Effort should feel hard but manageable. You could fit in a couple more if pushed.
• Cool down 10 min easy.

Long run

• Easy, comfortable pace. Duration matters more than speed.
• Feeling strong in the second half? Tackle the final 2 to 3 km at an easy goal-pace effort to practice pacing.
• Hydrate and fuel (gels, bananas) after 90 min.

Cross-training

• Low-impact, something you enjoy.
• Zone 2 heart rate, conversation intensity.
• Active recovery. Avoid heavy leg-focused work.

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Notes and tips

• Progressive overload: roughly 10% weekly increase. Cap it there to prevent injury.
• Recovery: sleep, hydration, carbs and protein.
• Gear: a watch or app with real-time pace and heart rate helps you adjust on the fly.
• Mental strategy: split the race into four 5-km segments. Focus on the current one.
• Pitfalls:
  1. Running long runs too fast. You’ll arrive at race day depleted.
  2. Cutting back on easy days. That’s when your body actually adapts.
  3. Pushing through pain. Small aches become big problems if ignored.
• Flexibility: some weeks will ask more than you have. Swap a tempo for an easy run or trim the long run by 2 km. What matters is consistency.

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FAQ

Q: What if I miss a key workout? A: Treat it as a rest day or fit in a shorter version later that week. Don’t stack two hard sessions back to back.

Q: My heart-rate zones don’t match the paces. Which do I follow? A: Whichever feels more reliable for you. Heart-rate: Zone 3–4 on tempos and intervals, Zone 2 for easy runs.

Q: I’m training on a hilly course. How do I adjust? A: Focus on effort rather than pace. Same perceived strain. Hills slow you, descents speed you up.

Q: Can I swap running for cycling? A: Yes, but only on easy or cross-train days. Keep intensity low and duration about the same.

Q: How do I know I’m ready for the race-pace rehearsal in week 10? A: You should have completed at least one tempo run and one interval session at goal pace without feeling completely drained.

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Closing and workout suggestion

A 2:20 unfolds through small wins. A morning where your legs feel good, a tempo that finally clicks, the growing confidence as your long runs extend. Stick with the plan, listen to your body, and each step moves you forward.

Try an intro tempo today: 5 km total, with the middle 2 km at goal pace (6:40 min/km). A first taste of race rhythm and a snapshot of where you stand.

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References

• 1/2 Marathon 12 Week Beginner | running Training Plan | TrainingPeaks (Blog)
• 1/2 Marathon 16 Week Beginner | running Training Plan | TrainingPeaks (Blog)