Marathon Interval Training: Which Sessions, and How Often?

Preparing for a marathon is primarily about building mileage and consistent long runs. However, interval training still plays an important role—provided it's programmed intelligently. Doing too much MAS (VMA) training, or doing it too frequently, can actually hinder your marathon preparation rather than improve it.

In this guide, you'll learn which interval workouts are most effective for marathon training, when to include them in your plan, the optimal training frequency, and the common mistakes to avoid.

Why Interval Training Is Important for Marathon Preparation

Many first-time marathon runners believe that only long runs matter.

That's a misconception.

Interval training provides several key adaptations that complement endurance training.

Benefit 1: Improve Your MAS (VMA)

Your Maximum Aerobic Speed (MAS) sets the ceiling for your endurance performance.

The higher your MAS, the faster your potential marathon pace can become.

Short intervals (200–1,000 m) are one of the best ways to improve it.

Benefit 2: Improve Running Economy

Training at faster speeds improves your running mechanics and neuromuscular efficiency.

As a result, maintaining marathon pace requires less energy.

Benefit 3: Practice Marathon Pace

Marathon-specific interval workouts—such as 3 × 4 km at marathon pace—teach your body to sustain your goal pace while allowing short recoveries, enabling you to accumulate more quality mileage than you could in one continuous effort.

Benefit 4: Raise Your Lactate Threshold

Threshold workouts, typically performed at half marathon pace, improve your ability to sustain a hard effort over a long duration.

This is one of the most valuable physiological adaptations for marathon runners.

The Four Types of Marathon Interval Workouts

Type 1: MAS (VMA) Intervals

Distance: 200–800 m

Intensity: 95–100% of MAS (VMA)

Recovery: 1–2 minutes of easy jogging

Examples

• 10–12 × 400 m at MAS pace with 90 seconds jog recovery
• 8 × 500 m at MAS pace with 90 seconds jog recovery

Best used during: Base-building and development phases, once per week.

Type 2: Threshold Intervals (Half Marathon Pace)

Distance: 1,000–3,000 m

Intensity: Half marathon pace

Recovery: 90 seconds to 3 minutes of easy jogging

Examples

• 4 × 2 km at half marathon pace with 2-minute recovery
• 3 × 3 km at half marathon pace with 3-minute recovery

Best used during: Development and marathon-specific phases, approximately every other week.

Type 3: Marathon Pace Intervals

Distance: 3–8 km

Intensity: Goal marathon pace

Recovery: 1–3 minutes of easy jogging

Examples

• 3 × 4 km at marathon pace with 90 seconds recovery
• 2 × 6 km at marathon pace with 2-minute recovery

Best used during: Marathon-specific phase (typically weeks 9–13), once per week.

Type 4: Long Intervals

Distance: 4–6 km

Intensity: Between half marathon pace and marathon pace

Recovery: 2–3 minutes of easy jogging

Example

• 3 × 5 km at a pace between half marathon pace and marathon pace with 3-minute recovery

Best used during: Marathon-specific phase, alternating with marathon-pace interval sessions.

How to Structure Interval Training Throughout Your Marathon Plan

Base

Weeks: 1–4

Recommended Interval Workouts: 1 MAS (VMA) workout per week (8 × 400 m)

Development

Weeks: 5–9

Recommended Interval Workouts: 1 MAS workout + 1 threshold workout every other week

Marathon-Specific

Weeks: 10–13

Recommended Interval Workouts: 1 MAS workout + 1 marathon-pace workout

Taper

Weeks: 14–16

Recommended Interval Workouts: 1 short MAS workout + 1 short marathon-pace workout

How Often Should You Do Interval Training?

For recreational marathon runners, the ideal frequency is one to two interval sessions per week, depending on experience and weekly mileage.

First marathon (30–45 km/week)

Once per week

Experienced marathoner (45–65 km/week)

1–2 sessions per week

Advanced marathoner (65–85 km/week)

2 sessions per week

Elite runner (90+ km/week)

2–3 sessions per week

Important: If you schedule two quality workouts each week, leave at least 48 hours between them.

A typical schedule is:

• Tuesday: MAS (VMA) workout
• Friday or Saturday: Marathon-pace workout

A Typical Marathon Training Week

Here's an example of how interval training fits into a marathon-specific training week.

Monday

Rest or 30-minute recovery run

Tuesday

MAS workout: 10 × 400 m, 90-second jog recovery

Wednesday

50–60 minute easy run

Thursday

Rest or cross-training

Friday

Marathon-pace workout: 3 × 4 km, 90-second recovery

Saturday

30–40 minute easy run

Sunday

Long run including a marathon-pace segment

How to Progress Your Interval Training

Progression 1: Increase the Number of Repetitions

Over a period of 4–6 weeks, progress from:

• 8 × 400 m
• 10 × 400 m
• 12 × 400 m

while maintaining the same target pace.

Progression 2: Increase the Length of the Intervals

Progress from:

• 400 m
• 800 m
• 1,000 m

while slightly reducing the total number of repetitions.

Progression 3: Reduce Recovery Time

Gradually shorten recovery from:

• 90 seconds
• to 75 seconds
• to 60 seconds

while maintaining the same pace.

This increases workout density without increasing intensity.

Progression 4: Increase Your Target Pace

As your MAS improves, update your training paces accordingly.

Reassess your MAS every 2–3 months.

Common Marathon Interval Training Mistakes

Mistake 1: Too Much MAS (VMA), Not Enough Marathon Pace

Improving MAS is valuable, but during the marathon-specific phase, marathon pace should become your priority, because that's the pace you'll race.

Mistake 2: Three Hard Workouts Every Week

Unless you're an elite athlete, two quality sessions per week are generally the maximum you can recover from while continuing to improve.

Mistake 3: Running the Intervals Too Fast

If your pace deteriorates from one repetition to the next, you started too aggressively.

Every interval should be completed at a consistent pace.

Mistake 4: Skipping the Warm-Up and Cool-Down

Always include:

• 15–20 minutes of easy running before the session.
• 10 minutes of easy jogging afterward.

Skipping these significantly increases your injury risk.

Where Should You Run Your Interval Workouts?

Several locations work well.

Athletics Track

The ideal option.

A forgiving surface, precise distances, and a safe environment.

Flat Road or Bike Path

An excellent alternative when using a GPS watch.

Park Loop

Convenient for runners training in urban areas.

Avoid

• Roads with heavy traffic
• Technical trails
• Uneven terrain

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Related Articles

→ Running Economy: The Real Secret Behind Endurance

→ Sub-1:35 Half Marathon Training Plan: Complete Analysis

→ How to Make Long Runs More Enjoyable and Effective

→ What vVO2max for a 3, 3:30, 4 or 4:30 Marathon? The Reference Table

→ Marathon Pace: How to Calculate and Maintain It Over 42.195 km