Overview

Easy running builds your base. Speed work builds your engine. Interval and tempo training are the two most effective ways to get faster — and you only need 1–2 speed sessions per week to see real results.

Golden Rule: Speed work should be purposeful. Every fast rep has a reason — don't just run hard for the sake of it.

Types of Speed Work

Session Type	What It Is	Effort	Benefit
Intervals	Short, fast bursts with recovery between	Hard (85–95% effort)	Improves VO2max (your body's maximum oxygen-processing capacity — the bigger your VO2max, the more energy you can produce) and top-end speed
Tempo runs	Sustained effort at "comfortably hard" pace	Moderate-hard (80–85%)	Raises lactate threshold (the intensity at which your muscles start producing fatigue-causing lactate faster than your body can clear it — raising it means you can run faster before fatigue sets in)
Fartlek	Unstructured speed play mixing fast and easy	Varies	Builds speed in a fun, flexible way
Strides	Short 20–30 sec accelerations	Fast but controlled	Improves running form and neuromuscular coordination

Interval Training

How It Works

Run fast for a set distance or time, recover, repeat. The recovery is just as important as the fast bit.

Common Interval Sessions

Session	Fast Reps	Recovery	Total Fast Running	Best For
Short intervals	8–12 × 200m	45 sec jog	1.6–2.4 km	Pure speed
Classic 400s	6–10 × 400m	90 sec jog	2.4–4 km	Speed endurance
800m reps	4–6 × 800m	2 min jog	3.2–4.8 km	VO2max
Kilometre reps	3–5 × 1 km	2–3 min jog	3–5 km	Race pace practice
Long intervals	3–4 × 1.5–2 km	3 min jog	4.5–8 km	Lactate threshold

How Fast Should Intervals Be?

Your 5K Time	200m Pace	400m Pace	800m Pace	1 km Pace
30:00	0:55	2:00	4:15	5:30
27:00	0:50	1:50	3:50	5:00
25:00	0:47	1:42	3:35	4:40
22:00	0:42	1:30	3:10	4:05
20:00	0:38	1:22	2:52	3:42

Tempo Runs

How It Works

Run at a pace you could hold for about 60 minutes in a race. It should feel comfortably hard — you can speak in short phrases but not hold a conversation.

Common Tempo Sessions

Session	Description	Duration
Continuous tempo	Warm up 10 min, run at tempo pace, cool down 10 min	20–40 min at tempo
Cruise intervals	Tempo pace broken into chunks: 4 × 8 min with 2 min jog	Same total time, slightly easier mentally
Progression run	Start easy, finish the last 15–20 min at tempo pace	40–60 min total

What's Tempo Pace?

Your 5K Time	Approximate Tempo Pace
30:00	6:30–6:45/km
27:00	5:50–6:00/km
25:00	5:20–5:30/km
22:00	4:40–4:50/km
20:00	4:15–4:25/km

Fartlek Training

Fartlek (Swedish for "speed play") is unstructured speed work. It's fun, flexible, and perfect for runners who find intervals too rigid.

Example Fartlek Sessions

Session	Description
Lamppost fartlek	Run fast between two lampposts, jog between the next two. Repeat for 20 min
Music fartlek	Sprint during the chorus, jog during the verse
Timed fartlek	1 min fast / 1 min easy × 10
Pyramid fartlek	1 min fast, 1 easy, 2 fast, 2 easy, 3 fast, 3 easy, then back down

Strides

Strides are short accelerations (20–30 seconds) at fast but controlled effort. Do them 2–3 times per week after easy runs.

How to Do Strides
After an easy run, find a flat stretch of 80–100m
Accelerate smoothly to about 90% effort over 20–30 seconds
Focus on smooth, relaxed form — not all-out sprinting
Walk or jog back to the start
Repeat 4–6 times

Putting It All Together: Weekly Structure

Day	Session	Type
Monday	Rest or easy run	Recovery
Tuesday	Intervals (e.g., 6 × 800m)	Speed
Wednesday	Easy run + 4 strides	Base + form
Thursday	Tempo run (20–30 min at tempo)	Threshold
Friday	Rest	Recovery
Saturday	Long easy run	Endurance
Sunday	Easy run or rest	Recovery

Common Speed Work Mistakes

Mistake	Problem	Fix
Going too hard on reps	Can't maintain pace — quality drops	If your last rep is much slower than your first, you started too fast
Not enough recovery	Reps become slower, form breaks down	Take the full recovery. Walk if needed
Too many speed sessions	Burnout and injury	1–2 per week is enough for most runners
Skipping the warm-up	Risk of muscle strain	Always warm up 10–15 min before speed work
All speed, no easy	Overtraining — you'll plateau or get injured	Follow the 80/20 rule: 80% easy, 20% hard

What's Next?

Speed work sorted:

Use Heart Rate Zone Training to nail your easy days
Target a PB with Improve Your 5K
Support your training with Strength Training for Runners

Interval & Tempo Training🔒

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