If you want to run faster, you have to practice running faster. Speed work—structured faster running—is how you develop the fitness to hit new PRs. But not all speed work is the same. Different workouts target different energy systems.
Interval training
Intervals are repeated hard efforts with recovery periods between them. They improve your VO2max—your body's ability to use oxygen—and make faster paces feel more sustainable.
Common interval workouts
- 400m repeats: 6-12 x 400m at 5K pace with 200m jog recovery
- 800m repeats: 4-8 x 800m at 5K-10K pace with 400m jog recovery
- 1000m/1200m repeats: 3-5 reps at 10K pace with 400m recovery
- Mile repeats: 3-4 x 1 mile at slightly faster than goal race pace
How hard should intervals feel?
Hard, but controlled. You should finish each rep feeling like you could have done one more at the same pace. If you're slowing significantly on later reps, you started too fast.
Tempo runs
Tempo runs are sustained efforts at your lactate threshold—the pace where lactate starts accumulating faster than your body can clear it. This pace is sometimes called "comfortably hard"—you can speak in short phrases but not hold a conversation.
Tempo run formats
- Classic tempo: 20-40 minutes at tempo pace (roughly your half marathon race pace)
- Cruise intervals: 3-4 x 10 minutes at tempo pace with 2-3 minutes easy jog between
- Tempo segments: Include a tempo portion in the middle of an easy run
Fartlek
Swedish for "speed play," fartlek is unstructured speed work. You vary your pace based on feel, terrain, or landmarks—sprint to that tree, easy to the next corner, tempo for two minutes, recover, repeat. It's a fun, flexible way to incorporate faster running.
Sample fartlek session
During a 40-minute run, include: 6-8 surges of 1-2 minutes at 5K effort, recovering with easy jogging between. Don't time the recoveries—run easy until you feel ready to go again.
Strides
Strides are short accelerations (20-30 seconds) where you gradually build to near-sprint speed, then decelerate. They improve running economy and neuromuscular coordination. Do 4-6 strides after easy runs, 2-3 times per week.
When to add speed work
Build an aerobic base first. If you're new to running, spend 2-3 months running consistently before adding structured speed work. Once you have a base, add one speed session per week initially, building to two if your body handles it well.
Recovery between speed sessions
Allow at least 48-72 hours between hard workouts. Your easy runs should be truly easy—Zone 1-2 heart rate, conversational pace. Easy days are not "just slow"—they're essential for absorbing the benefits of your hard work.
Common speed work mistakes
- Running too fast on the first rep and fading
- Not taking enough recovery between reps
- Doing speed work when exhausted from other runs
- Skipping the warm-up (always run 10-15 minutes easy first)
Speed work is challenging but rewarding. When you nail a workout you couldn't have completed months ago, you know you're getting faster.