Aerobic speed is the middle gear.
Imagine how fast you could go at your top end, if you could already go fast at your aerobic level. That is aerobic speed — and it is completely trainable.
§ 01 · What it is
Super simple, deeply trainable.
Aerobic speed is how fast you can run, ride, or swim while staying aerobic — below the point where lactate begins to climb. The higher that ceiling sits, the more of your racing you can do cleanly.
§ 02 · Aerobic power
What speed actually is.
A component of aerobic power. Nothing more.
Speed is not a moral quality. It is not courage, or willingness, or how badly you want it on the day. Speed is a component of aerobic power. That is the useful definition, and it changes how you train.
The athlete with a higher aerobic ceiling goes faster at the same effort. Not because they try harder, but because the engine beneath the speed is bigger. Build the engine, the speed follows.
This is the piece that takes a while to accept. It rewards patience in a way most training does not.
§ 03 · How to train it
Four honest measures.
Pick your instrument. Use it honestly.
MAF heart rate. Phil Maffetone’s formula — 180 minus your age, adjusted — gives you a ceiling. Hold pace at that ceiling and watch the pace improve over months. When the same heart rate produces a faster split, aerobic speed is going up.
Checkpoints. A repeatable route, run or ridden at the same perceived effort, logged monthly. The number is not the point. The trend is.
Watts at aerobic threshold. On the bike, the cleanest proxy. Track the watts you can hold at the top of aerobic — where breathing is still conversational. Protect it ruthlessly.
Swim aerobic speed. A descending set held at steady effort. The times come down. The stroke rate stays the same. That is aerobic speed in the water.
Two athletes, one pace.
Both running 4:00/km. One is bleeding lactate, one is not. The difference is not fitness as a feeling — it is where the curve starts to rise.
§ 04 · Sustainability
Show up, don’t blow up.
The ceiling only rises if you keep training.
Aerobic speed responds to consistency, not heroics. Ten weeks of honest sub-threshold work will do more than any single sharp session ever will. The trap is boredom — the pace feels easy, and athletes want to push it. Resist.
When life interrupts, the fallback is more aerobic work, not less. A shorter session held cleanly at aerobic speed keeps the adaptation alive. A smashed session on tired legs sets it back.
The single best predictor of a good race season is uninterrupted aerobic training in the three months before it. Not intensity. Uninterrupted.
Speed is a component of aerobic power. Nothing more. Nurture the engine, and the speed will walk in on its own.§ Notebook · after a long ride, back at the shed
§ 05 · The payoff
You lead, they bleed.
The race is usually decided here.
On race day, the athlete with the higher aerobic ceiling is doing the first two-thirds of the race at a cost that nobody else can match. They are not faster because they are trying harder. They are faster because the same pace, for them, is cheap.
By the time the front of the race wants to push, the ones who earned their aerobic speed are fresh. The ones who skipped it are already in the red.
That is the whole quiet case for aerobic speed. Boring to train, decisive when it matters.
§ Also in Physical