Race Shape Explained — How Do You Know You're Ready?

Three weeks before your marathon. You've trained for months. But are you really ready? Is your volume enough? Have you done enough long runs? Where are the gaps?

Most training apps give you no answer to this question. They show you CTL/ATL/TSB as abstract numbers, or a "fitness score" that has nothing to do with your race distance. A Garmin form gauge tells you "productive" — whatever that's supposed to mean.

Race Shape is Yama's attempt to answer this question concretely. In this article I'll explain the idea behind it, the math, and how to interpret the value for yourself.

The core idea: two pillars of preparation

In sports science there are two main components of endurance race preparation — this has been uncontested in the literature since Daniels and Lydiard:

• Volume — how many kilometers per week do you average? Your aerobic base builds over months, not weeks.
• Specific long runs — have you done enough long runs that approach race distance? This trains glycogen management, leg musculature, mental toughness.

Race Shape combines both into a percentage. 100% means: sufficiently prepared for the distance. Above 100%: solid to very good. Below 100%: preparation still building, risk of a DNF or a significantly slower time.

How it's calculated exactly

Each component gets a percentage relative to the requirements for your target distance. Then both are combined with weights:

The weights are distance-specific. For short distances volume counts more; for long distances long runs become more important:

The logic: you run a 5k primarily off your aerobic capacity — general weekly volume is decisive there, a 30 km long run doesn't really help. In a marathon, by contrast, the final 10 km are the most critical phase: without enough specific long runs, you blow up.

How much volume is "100%"?

That depends on your target time. Someone aiming for a 2:30 marathon needs different volume than someone targeting 4:30. Yama follows Daniels/Lydiard:

For a half marathon with a target under 1:35, that would be roughly 45 km/week and an 18 km long run. Yama derives these values for each distance from your specific target time — or, if no target is given, from your predicted best time. You can produce such a prediction from a recent race time yourself with the pace calculator.

What is a "qualifying" long run?

Not every run counts. Yama defines qualifying long runs as runs that reach at least 85% of the target long-run distance. Example: target = 25 km long run. Threshold = 21 km. Every run over 21 km in the last 10 weeks counts.

The long-run component then scores how many qualifying runs you had in the last 10 weeks:

• 0 runs: 0% long-run score
• 1–2 runs: 40%
• 3–4 runs: 70%
• 5–6 runs: 90%
• 7+ runs: 100% — sufficient long-run experience

Plus a bonus for your longest run: if your longest run was near or above the target distance, there's up to +20%.

A concrete example

Calculation:

• Volume: 50/65 = 77%
• Long runs: 4 qualifying = 70% base score + bonus for the 28 km run (+10%) = 80%
• Marathon weighting: 67/33

78% — solidly mid-pack preparation. The marathon is doable, but the 3:15 target is optimistic. A realistic target time is more like 3:25–3:30. Concrete takeaway: volume was a bit too low over 6 months, and that can't be made up three weeks out.

What Race Shape does NOT measure

Race Shape is a volume and specificity indicator. It says nothing about:

• Day-form — whether you're fit or sick on race day
• Pace specificity — whether you did tempo runs at marathon pace
• Nutrition and race-day strategy — glycogen management, pacing
• Mental strength — not measurable
• Weather and course — a hilly marathon at 28°C is different from Berlin at 8°C

So Race Shape is no cure-all. It's a well-founded volume check — no more, but no less. If your Race Shape is below 80% three weeks before the race, you know the risk is high.

How to improve your Race Shape

Important: Race Shape is a long-term indicator. Six months of volume can't be turned around in two weeks. But:

If you still have > 12 weeks

• Increase volume slowly (max +10% per week)
• Build in a weekly long run, a really long one every 2–3 weeks
• Training injury-free matters more than pushing volume

If you have 4–12 weeks

• Too late for a volume build — focus on long-run quality
• 2–3 truly long runs (e.g. 28–32 km for a marathon) if physically feasible
• Pace specificity: long runs with marathon-pace segments at the end

If you have < 4 weeks

• Peak phase — hold volume or ease slightly down, keep intensity
• Last long run 2–3 weeks before the race
• Accept Race Shape as it is, adjust your target time

Conclusion

Race Shape is a concrete answer to a concrete question: Am I ready? It doesn't replace the gut check just before the start. But it gives you a clear picture 6–12 weeks out of where you stand — and above all why.

The key insight: volume over 6 months is by far the strongest predictor for long-distance races. Someone who starts three weeks before the marathon at 30 km/week can't expect to finish in 3:00 — no matter how much talent or willpower is involved. Tendons, muscles and the aerobic system take months to adapt, and that time can't be shortcut.

The number sometimes stings, because it's more honest than the gut feeling three weeks before the start. But that's exactly why it's useful: better to know six weeks out that the volume is missing than to find out at kilometer 32.