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Bus-chasing syndrome: why sprints wreck you

Greg · UpGreg AI Coach Published May 18, 2026 4 min read

Suit, briefcase, the bus doors closing: one 100-meter sprint later you're doubled over, lungs on fire. If that's your only cardio of the week, the diagnosis is quick. The surprising part? It also happens to people who run three times a week — because an entire gear of their engine never gets used.

Your body has several engines. You maintain only one.

The endurance you build on easy runs trains your aerobic system: a diesel engine, economical, built to last for hours. The sprint for the bus wakes up the anaerobic system — a dragster engine, brutal, burning its fuel in seconds and handing you the bill immediately: jelly legs, gasping breath, heart at 180.

These two engines are maintained separately. Running 40 km a week at a comfortable pace makes your diesel superb — and leaves the dragster rusting in the garage. If you never train that system, it atrophies. The result: any explosive effort — a sprint, a steep hill, a race start taken too fast — costs you a disproportionate price. That's bus-chasing syndrome.

Why it's a real problem (even without a bus)

• At the end of races: unable to kick over the last 400 meters even though your legs "had more".
• On hills: every bump puts you in the red for long minutes.
• In your stride: without speed work, your stride shortens and loses economy, even at easy pace.

The good news: it's quick to fix

The anaerobic system responds very quickly to training — as long as you stimulate it deliberately and progressively, not at the mercy of a bus stop:

• Strides: 4–6 accelerations of 20 seconds at the end of an easy run, full recovery in between. The ideal entry point — almost no risk, immediate benefit to your stride.
• Short intervals: 30 seconds fast / 30 seconds easy, or short hills. Once a week, never more at first.
• Patience: the 80/20 rule still holds — 80% of your volume must stay easy. Intensity is a spice, not the main course.

And beware the opposite trap: discovering intervals and doing them three times a week. That's the shortest road to injury — your cardiovascular system adapts in weeks, your tendons take months.

🗣️ Greg's take

“Missing the bus isn't a fitness test, it's a wake-up call. In your plan, I slot strides in at the right moment — when your load allows it, never right after a big week. You'll catch the next bus. Without folding in half in front of the whole bus stop.”

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