Understanding Interval Training

Interval training alternates between hard efforts and recovery periods. This structure allows you to accumulate more time at high intensities than continuous hard running.

Why Intervals Work

Physiological benefits:

• Increases VO2max (aerobic capacity)
• Improves running economy
• Raises lactate threshold
• Builds speed and leg turnover
• Develops mental toughness

The magic: You can run 20-30 minutes at hard intensities by breaking it into intervals, whereas you might only sustain 10-15 minutes continuously.

Interval Types Explained

VO2max Intervals (3-5 minutes)

Purpose: Develop maximal aerobic capacity

Effort: Hard but controlled—roughly 5K race effort or slightly faster

Example: 5 x 1000m with 2-3 min recovery

When to use: Build phase, 8-12 weeks before goal race

Short Intervals (200-400m)

Purpose: Develop speed and leg turnover

Effort: Fast—faster than 5K pace

Example: 10 x 400m with 90 sec recovery

When to use: Throughout training, especially peaking phase

Tempo Intervals (Cruise Intervals)

Purpose: Raise lactate threshold

Effort: Comfortably hard—roughly half marathon to 15K effort

Example: 4 x 8 min at threshold with 2 min jog

When to use: Base and build phases

Race-Specific Intervals

Purpose: Practice goal race pace

Effort: Goal race pace for target distance

Example: 6 x 1 mile at marathon pace with 1 min recovery

When to use: Final 6-8 weeks before race

Recovery Between Intervals

Recovery is as important as the work:

Interval Length	Typical Recovery
200m	30-60 seconds
400m	60-90 seconds
800m	90-120 seconds
1000m	2-3 minutes
1200m+	2-4 minutes
Tempo intervals	1-2 minutes

Recovery style:

• Jog slowly (most common)
• Walk (for very hard efforts)
• Standing rest (for short sprints)

Warm-Up and Cool-Down

Warm-Up (15-20 minutes)

1. Easy jog: 10-15 minutes
2. Dynamic stretches: leg swings, high knees, butt kicks
3. Strides: 4-6 x 80-100m accelerations
4. Mental prep: visualize the workout

Cool-Down (10-15 minutes)

1. Easy jog: 10-15 minutes
2. Walking: 2-3 minutes
3. Static stretching: major muscle groups
4. Hydration and nutrition

Common Mistakes

Going too fast too early: Start conservatively. Later intervals should be as fast or faster than early ones.

Not enough recovery: Full recovery between intervals matters. Don't rush it.

Too much speedwork: Once or twice per week is enough. More isn't better.

Same workout every week: Vary interval types to develop different systems.

Skipping warm-up: Cold muscles don't perform well and injury risk increases.

Progressing Interval Workouts

Beginner approach:

• Start with shorter intervals (200-400m)
• Longer recovery periods
• Lower total volume
• Focus on form over pace

Progression options:

• Add repetitions (5 x 400 → 6 x 400)
• Lengthen intervals (400m → 600m → 800m)
• Reduce recovery time
• Increase pace (last option)

Weekly Placement

Best days for intervals:

• After a rest day or easy day
• Not the day before a long run
• Not the day after a hard workout

Typical week:

• Monday: Rest or easy
• Tuesday: Intervals
• Wednesday: Easy
• Thursday: Tempo or easy
• Friday: Rest or easy
• Saturday: Long run
• Sunday: Easy or rest

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Intervals should feel hard but achievable. If you're dreading them or failing to complete them, reduce the intensity or volume.

Calculate your training paces with our Pace Zone Calculator.