Why Your Interval Work Isn’t Actually Speed Training

Raising the Floor, Raising the Ceiling:

Why You Need Both Threshold & Speed Work

Runners love to call intervals “speed work.” But lumping everything that’s faster than your easy run together is a mistake. The reality is what most people call speed work is speed endurance, VO2 Max, or Threshold work. So what’s the difference?

I like to think of training like building a house: threshold work raises your floor, while speed work raises your ceiling. The stronger your foundation, the faster your “easy” pace becomes. The higher your ceiling, the more top-end speed you have, the higher your potential race pace.

Threshold Training: Raising the Floor

Threshold work is what makes you durable—able to hold a strong effort without blowing up. This type of training teaches your body to clear lactate efficiently, meaning you can run faster for longer without hitting a wall.

A lot of runners think threshold work means gutting out tough reps, but the key is control. You should be working hard, but not redlining. Some classic workouts include:

✅ Steady-state runs – slightly below threshold, keeping things smooth

✅ Tempo runs – 15-30 minutes at threshold pace (that comfortably hard effort)

✅ Cruise intervals – shorter reps with quick recoveries to stay in the zone

Speed Training: Raising the Ceiling

True speed work isn’t grinding through 400s or 800s at VO2 max —it’s about running fast at or near max speed with full recovery. This type of training sharpens your mechanics, improves your efficiency, increases your speed reserves and makes race paces feel easier. The stronger your top-end speed, the less effort it takes to hold race pace. Ever wonder why elite marathoners do sprint work? It’s not to run a sub-10-second 100m—it’s to make 5:00/mile pace feel relaxed.

Some of my go-to speed workouts:

⚡ Short sprints (50m-150m) – all-out, max effort, full recovery

⚡ Flying sprints – gradual acceleration into top speed

⚡ Hill sprints – 8-10 second sprints uphill (low risk, high reward)

Putting It All Together

If you only focus on threshold work, you’ll be strong but lack that extra gear. If you only sprint, you’ll be powerful but have no endurance. The best runners train both, making sure their floor is high and their ceiling is even higher.

- Coach Brandon