Build-Up Training Plan
"Ramp mileage too fast and you get hurt" — so the sports-medicine standard is to increase by 10% or less per week.
Enter your current and target mileage and we build an injury-free plan to get there.
Average weekly distance over the last 4 weeks
Full-marathon prep: 60–80 km / Half: 40–50 km
Estimated completion
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weeks
Total increase
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km / week
Week-by-week mileage plan Auto-generated
| Week | Total distance | Split (daily example) | Notes |
|---|---|---|---|
| Please check your inputs | |||
Is the 10% rule really scientific?
"Do not increase weekly mileage by more than 10%" — a rule runners have treated as gospel since the 1990s. Is there real evidence?
Historical background
- Joe Henderson (Runner's World) first popularized it in a 1980s column
- Later the ACSM and the American orthopedic community confirmed that "sudden mileage jumps are a major cause of overuse injury"
Modern research findings
- Buist et al. (2008) — a randomized trial of 532 novice runners, 10% group vs. standard group: no statistically significant difference in injury rate
- But the group that jumped 30%+ had a clearly higher injury rate
- Conclusion: 10% is not a magic number, but increasing by more than 20% is risky
3 weeks build + 1 week recovery — why?
- The adaptation cycle for muscle, bone, and ligament is about 21 days (3 weeks)
- 3 weeks of stimulus + 1 week of recovery = starting the next cycle stronger
- A recovery week is standard at 70–80% of the previous week's distance
This calculator's algorithm
- Each week: (previous week's distance) × (1 + increase rate)
- Every 3 weeks, the recovery week drops to 75% of the previous build week
- Right after a recovery week, resume from the previous peak × (1 + increase rate)
- Ends automatically once the target distance is reached
Daily split example
- 30–35% of weekly distance goes to one longest LSD run
- The rest is split into 3–4 short easy runs + one interval session
- Rest is recommended on Monday and Friday
Sources: Buist I et al. (2008) BJSM · Nielsen RO et al. (2014) JOSPT · ACSM Position Stand
A build-up chart is useless within a week
Even the best plan falls apart after one rainy day and one work dinner. Mileage you have promised a crew, though, tends to get done — the power of a social commitment.
