The Moment the Clock Started Ticking

I was waiting at the curb of my neighborhood coffee shop, watching the morning rush. A runner in a bright teal shirt sprinted past, glancing at his watch and whispering, “One‑twenty‑five, baby.” In that split second I felt the familiar mix of awe and envy – the same feeling that sparked my own half‑marathon dream. What if I could turn that whisper into a reality?

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The Goal: 13.1 mi in 1:25:00

A 1:25 half marathon translates to an average pace of 6:52 per mile (or 4:15 per kilometer). Reaching that speed means you’ll need:

• Speed – the ability to comfortably hold sub‑7 min/mile paces for longer than 5 km.
• Endurance – a solid aerobic base that can sustain 10‑12 mi at a steady effort.
• Mindset – confidence in your pacing, patience for the grind, and resilience on tough days.

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Are You Ready? – Pre‑Requisites

Before you lace up for this plan, check that you meet the following baseline:

Requirement	What It Looks Like
Current Half‑Marathon PB	1:35 – 1:40 (or faster). If you haven’t raced the distance, you should be able to run 10 mi at 8:00 min/mile comfortably.
Weekly Mileage	20‑30 mi per week, spread over at least 4 days.
Recent Consistency	No missed runs for the past 2 weeks; you’ve been running at least 3 days a week.
Injury‑Free	No lingering aches that affect your ability to run a moderate distance.

If you’re close but not quite there, add a 2‑week “base building” block (easy runs, a weekly long run, and optional cross‑training) before starting.

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How the Plan Works

The plan revolves around five core workout types. Each has a purpose and a suggested effort zone:

Workout	Purpose	Typical Pace / Effort
Easy Run	Build aerobic mileage while promoting recovery.	Zone 2 – 8:30‑9:30 min/mile (conversation pace).
Tempo Run	Raise lactate threshold – the pace you can sustain “comfortably hard.”	Zone 3‑4 – 7:00‑7:30 min/mile (≈85‑90 % of max HR).
Interval / Speed Session	Sharpen leg speed and improve VO₂ max.	Short bursts at 5:30‑6:00 min/mile (Zone 5) with equal rest.
Long Run	Extend endurance and teach the body to burn fat efficiently.	Zone 2‑3 – 8:00‑8:45 min/mile, finish the last 2 mi at goal race pace.
Recovery / Cross‑Training	Allow adaptation while reducing impact stress.	Light activities (cycling, swimming, yoga) at Zone 1.

Pacing tips – Use a GPS watch or a phone app to monitor your average pace, but also learn to “feel” the zones: conversation‑friendly for easy, light‑breathing for tempo, and hard‑to‑talk‑for intervals.

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12‑Week Training Calendar

Week	Mon	Tue	Wed	Thu	Fri	Sat	Sun
1	Rest / Cross‑Train	Easy 4 mi (Z2)	Tempo 4 mi (Z3)	Easy 3 mi (Z2)	Rest	Long 7 mi (Z2)	Recovery 3 mi (Z2)
2	Rest	Easy 4 mi	Interval 5×800 m (5:45 / 800 m)	Easy 3 mi	Rest	Long 8 mi (last 2 mi @ 7:00)	Recovery 3 mi
3	Rest	Easy 5 mi	Tempo 5 mi (7:15)	Easy 3 mi	Rest	Long 9 mi (Z2)	Recovery 3 mi
4	Rest	Easy 5 mi	Interval 6×800 m (5:45)	Easy 3 mi	Rest	Long 10 mi (last 3 mi @ 7:00)	Recovery 4 mi
5	Rest	Easy 5 mi	Tempo 5 mi (7:00)	Easy 4 mi	Rest	Long 11 mi (Z2)	Recovery 4 mi
6	Rest	Easy 5 mi	Interval 4×1 mi (5:50)	Easy 4 mi	Rest	Long 12 mi (last 4 mi @ 6:55)	Recovery 4 mi
7	Rest	Easy 5 mi	Tempo 6 mi (6:55)	Easy 4 mi	Rest	Long 13 mi (Z2)	Recovery 4 mi
8	Rest	Easy 5 mi	Interval 5×1 mi (5:45)	Easy 4 mi	Rest	Long 14 mi (last 5 mi @ 6:55)	Recovery 4 mi
9	Rest	Easy 5 mi	Tempo 6 mi (6:50)	Easy 4 mi	Rest	Long 12 mi (cut‑back, Z2)	Recovery 4 mi
10	Rest	Easy 5 mi	Interval 6×800 m (5:40)	Easy 4 mi	Rest	Long 15 mi (last 6 mi @ 6:55)	Recovery 4 mi
11	Rest	Easy 4 mi	Tempo 5 mi (6:45)	Easy 3 mi	Rest	Long 10 mi (race‑pace finish)	Recovery 3 mi
12 (Race Week)	Rest	Easy 3 mi	Tempo 3 mi (goal pace)	Rest	Easy 2 mi	Race Day – 13.1 mi @ 6:52 / mi	Rest

All easy runs can be swapped for a low‑impact cross‑training day if you feel unusually fatigued.

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Detailed Workout Descriptions

Easy Run (Z2)

1. Warm‑up with 5‑10 min of brisk walking or light jogging.
2. Run at a pace where you can hold a full conversation – roughly 8:30‑9:30 min/mile.
3. Finish with 5 min of easy strides (20‑30 sec) to keep legs fresh.

Tempo Run (Z3‑4)

1. 10‑minute warm‑up at easy pace.
2. 20‑30 min at “comfortably hard” – you can speak in short phrases, heart rate around 85‑90 % of max.
3. Cool‑down 10 min easy.

Interval / Speed Session (Z5)

1. Warm‑up 10‑15 min easy + dynamic drills (leg swings, high knees).
2. Run the prescribed distance (e.g., 800 m) at target interval pace (≈5:45 / 800 m).
3. Recover jog or walk for the same amount of time.
4. Repeat the set number of times.
5. Cool‑down 10 min easy.

Long Run (Z2‑3)

1. Begin at an easy aerobic pace (Zone 2).
2. Gradually increase to a slightly faster pace after the first half if you feel good.
3. In the final 2‑4 mi, run at goal race pace (6:52 / mi) to practice pacing on tired legs.
4. End with a 5‑10 min walk or very easy jog.

Recovery / Cross‑Training

Choose a low‑impact activity you enjoy – cycling, swimming, elliptical, or a yoga flow. Keep intensity low (Zone 1) and duration 30‑45 min.

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Notes & Tips

• Progression – If a week feels too hard, repeat the previous week before moving forward. Conversely, if you breeze through, you can add 0.5‑1 mi to the long run.
• Nutrition – Fuel longer runs with 30‑60 g of carbs per hour (e.g., a banana + sports drink). Stay hydrated; a simple electrolyte tablet can make a big difference.
• Sleep & Recovery – Aim for 7‑9 hours nightly. Use foam‑rolling or gentle stretching after hard sessions.
• Pacing Adjustments – Use the “talk test” for easy runs, heart‑rate zones for tempo, and a GPS watch for interval splits. If you’re consistently faster or slower than the suggested paces, adjust the whole plan proportionally.
• Common Mistakes – Skipping easy days, ignoring pain, or trying to run all miles at race pace. Remember: consistency beats intensity.
• Training Principles – This plan applies personalized pace zones, progressive overload, and built‑in adaptation days. By tracking effort and adjusting on the fly, you get real‑time feedback that keeps you on target without a rigid script.

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Frequently Asked Questions

Q: I missed a key workout. What should I do? A: If you miss a tempo or interval, replace it with an easy run and keep the long run that week. Don’t cram two hard sessions together.

Q: My current half‑marathon PB is 1:38. Can I still try this plan? A: Yes, but consider adding a 2‑week base block to raise your weekly mileage to ~25 mi before starting.

Q: How do I know if I’m in the right pace zone without a heart‑rate monitor? A: Use perceived effort: easy = conversational, tempo = “just a bit uncomfortable,” interval = “hard to speak, breathing heavy.”

Q: I’m dealing with a minor niggle. Should I keep training? A: Replace the hard day with cross‑training or an easy run. If pain worsens, rest and consult a professional.

Q: Can I swap a Saturday long run for a Sunday? A: Absolutely. Just keep at least one rest day before the race‑week taper.

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The Finish Line (and Beyond)

The beauty of chasing a 1:25 half marathon is that every mile you log teaches you something—about your body, your mindset, and the simple joy of moving forward. Stick with the plan, listen to your body, and celebrate the small victories: a smooth interval, a steady tempo, a long run that feels easier than the week before.

Workout of the Week Suggestion:

Start with a “Goal‑Pace Intro” – 1 mi easy, 3 mi at 6:55 / mi, 1 mi easy. This familiarises you with the target speed without the pressure of a full race.

Now lace up, trust the process, and enjoy the road ahead. Your 1:25 half marathon is waiting—one step at a time.

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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)