Breaking 90 Minutes for the Half Marathon — a 14-Week Plan

Every post up to 10K was about shaving pace. The half marathon is the first race where distance becomes the enemy. 21.0975 km. 90 minutes. Pace: 4:15/km.

4:15/km isn't a fast number — if you already run 10K in 41–43 minutes, it's actually slower than your 10K race pace. The problem is holding it over twice the distance, twice the time. That makes the half a game of threshold, endurance, and fueling — not raw speed.

This plan assumes you can already run 10K in 42–44 minutes. If not, climb up from sub-50 or sub-40 first.

What 90-minute pace feels like

• A short sentence is possible — slightly easier than a 10K race
• Breathing: roughly 3 in, 2 out
• Heart rate: 85–88% of max (kept lower than a 10K)
• The right pace feels like "I could probably go a bit faster" — that restraint is correct

The key is that this pace is slower than your 10K race pace. You're not running fast; you're holding a sustainable pace dead steady for ninety minutes.

Four differences between 10K and the half

	10K (sub-40–50)	Half (sub-90)
Deciding variable	VO2max + threshold	threshold + endurance
Longest long run	18–24 km	24–28 km
In-race fueling	none	required (1–2 gels)
Pacing restraint	important	decisive

The half is long enough that threshold (lactate) and glycogen endurance set the result, not VO2max. And past ninety minutes your carbohydrate stores start to run dry — so for the first time you learn how to eat while running.

The 14-week plan

Four blocks. Weeks 4, 8, and 12 are cutback weeks.

Wk	Mon	Tue	Wed	Thu	Fri	Sat	Sun
1	Rest	8K Easy + strides	10K Easy	8K Tempo @4:30	Rest	16K Long	6K Recovery
2	Rest	9K Easy + strides	10K Easy	6×1km @4:05	6K Easy	18K Long	6K Recovery
3	Rest	10K Easy + strides	10K Easy	10K Tempo @4:25	6K Easy	20K Long	6K Recovery
4	Rest	8K Easy	8K Easy	5×1km @4:05	Rest	14K Long	Cutback wk
5	Rest	10K Easy + strides	12K Easy	10K Tempo @4:25	6K Easy	20K Long	7K Recovery
6	Rest	10K Easy	12K Easy	4×2km @4:15 (90s jog)	6K Easy	22K Long	7K Recovery
7	Rest	11K Easy + strides	12K Easy	12K Tempo @4:25	6K Easy	23K Long (last 5km @4:15)	7K Recovery
8	Rest	8K Easy	10K Easy	5×1km @4:00	Rest	16K Long	Cutback wk
9	Rest	10K Easy + strides	12K Easy	3×3km @4:20 (2 min jog)	8K Easy	24K Long (last 8km @4:15)	7K Recovery
10	Rest	10K Easy	12K Easy	14K Tempo @4:25	8K Easy	26K Long	7K Recovery
11	Rest	11K Easy + strides	12K Easy	2×5km @4:18 (3 min jog)	8K Easy	24K Long (last 10km @4:15)	7K Recovery
12	Rest	8K Easy	10K Easy	6×1km @4:00	Rest	18K Long	Cutback wk
13	Rest	8K Easy + strides	8K Easy	10K @4:15 (race pace)	6K Easy	14K Long	6K Recovery
14	6K Easy	Rest	6K Easy + strides	5K @4:15	Rest	Half Race	Recovery

Five to six runs a week, 60–75 km. Bracket Tempo and Interval sessions with 1–2 km warm-up and cool-down (table distances are the main set).

Four core workouts

1. Tempo / Threshold — the half's engine

10–14 km @4:25 (10 sec faster than goal)

Most of a half is decided here. It holds you at threshold for 40–60 minutes — longer than a 10K because the race is longer. If you can finish 14K @4:25 by week 10, you've got 80% of sub-90.

2. Race-pace long runs — the half's key weapon

Goal-pace blocks late in the long run: last 5 → 8 → 10 km

This is what sets distance training apart. Not just running long and slow, but holding race pace on already-tired legs. Running the last 5 km of a 23 km long run at 4:15 simulates the back half of the race exactly.

3. Intervals — keeping the top end

5–6×1km @4:00 (faster than goal)

The half isn't a VO2max race, but cut intervals entirely and 4:15 starts to feel fast. Once a week, faster-than-goal 1 km reps keep your ceiling up so race pace feels relatively easy.

4. Long Run — distance itself

Longest 26–28 km @5:15–5:45

The biggest change in half training. Long runs go past race distance (21 km) to 26–28 km. The goal is bigger glycogen stores, capillary density, and a body built to run past two hours. Pace is one to one-and-a-half minutes slower than goal — except on days with race-pace blocks.

For the first time: eating while running

Past ninety minutes your carbohydrate stores start to empty. The in-race fueling you never needed for a 10K decides the half.

• One gel around the 45–55 minute mark (~11–13 km), with a sip of water.
• For a 90-minute race, one gel is enough. Sensitive stomach? Take it in two halves.
• Caffeinated gels help late-race focus — but only if you normally take caffeine.
• At aid stations, take a sip while holding pace, don't walk. Stopping to drink a full cup breaks your rhythm.

Recovery — more important as distance grows

Once long runs pass two hours, recovery is more than half the training.

• Sleep 8 hours — guard it especially the night after a long run
• Protein 1.6–1.8 g/kg/day
• Carbs 6–8 g/kg/day — start filling from the night before a long run
• Water 2.5–3 L/day + electrolytes on hot days
• Within 30 min of a long run, carbs + protein (the glycogen golden window)
• Massage / foam roll 2–3× a week

Injury warning signs

Any of these and you take a full week off:

1. Inner-knee pain on stairs (runner's knee)
2. Achilles soreness on the morning's first step
3. Heel pain in the morning (plantar fasciitis)
4. Front-shin swelling (shin splints)
5. Resting HR 5+ BPM up for three straight days

Longer distance means fatigue accumulates faster. One week becomes six.

Race-day strategy

A sub-90 half is even pace, or a very slight negative split. The penalty for going out hard is far crueler than a 10K — there's more race left.

Segment	Pace	Note
1–5 km	4:18	Suppress the excitement, open conservative. No greed
6–13 km	4:15	Hit goal exactly. Gel at 11–13 km
14–18 km	4:13	Lift gently, control the breath
19–21 km	4:10 → empty it	Last 2 km, everything you've got

Open the first 5 km at 4:08 and you'll blow up by 16 km. Accumulated debt collapses your pace by 30 seconds over the final 5 km. The most common half failure is "I felt too good early."

• Two days out: 6K Easy + 4 strides. Otherwise rest.
• Day before: full rest, extra carbs (no need for full carb-loading), no alcohol.
• Race morning: familiar breakfast 2.5–3 hours out. Caffeine fine. Leave time for the bathroom.
• Warm-up: 1.5K Easy + dynamic stretching + 3 strides, 20 minutes before. Lighter than a 10K — you've got ninety minutes to run.

Sub-90 done. Now what?

Congratulations — inside the top 10% of half-marathon field finishers.

Next:

• Sub-85 half (4:02/km) — threshold up another notch
• Sub-3:15–3:30 marathon — turn toward distance (a completely different game)
• Sub-40 10K (4:00/km) — if you'd rather return to speed; see here

If 10K was "how fast," the half is "how long can you hold that speed." The marathon asks the same question twice over.

If fourteen weeks felt long, you did them right. Distance is honest — it pays back exactly what you put in.