天草一周！あまいちグランフォンド2026 takes place on Sat, Dec 12, 2026 in Amakusa, Japan. The main route is 140 km.
- Date
- Sat, Dec 12, 2026
- Start
- Amakusa 🇯🇵
- Distance
- 140 km
- Level
- Open to all
A two-day cycling event taking participants on routes of varying distances around the Amakusa region in Kumamoto Prefecture, featuring scenic coastal and mountain landscapes.
Official event pageWhat this race demands
This 140-kilometer December cycling event demands prolonged endurance and steady pacing across coastal and mountain terrain in Amakusa.
Endurance capacity
Covering 140 kilometers requires a well-developed aerobic base and the ability to sustain continuous pedaling for many hours.
Terrain versatility
The inclusion of both coastal and mountain landscapes means riders must manage varied topography, including sustained climbs and descents.
Winter weather management
Taking place in December, participants need to manage cooler temperatures and potential wind exposure along coastal sections.
A ride of this distance will likely exceed 4 to 6 hours, requiring a consistent intake of 60 to 90 grams of carbohydrates per hour to maintain energy levels.
What would it take you?
Pick the level closest to yours for an estimate of finish time on this course and the training a solid preparation needs.
Estimated finish
4:20–5:15
Peak-week training
6–8 h/week
A model estimate from distance, climbing and level, not a promise. Conditions, drafting and pacing move it.
IntervalCoach turns those weekly hours into a concrete plan built around your actual fitness. Start with this race as your goal
Your road to race day
Race day at 天草一周！あまいちグランフォンド2026 is 16 weeks away. This is how a coach divides that time. The first phase starts now.
01Base4 weeks · Aug 23, 2026 – Sep 19, 2026
Aerobic foundation: mostly steady endurance work that grows the aerobic engine and the durability the later phases stand on.
02Build6 weeks · Sep 20, 2026 – Oct 31, 2026
Progressive overload: training load climbs in waves, with harder weeks stacked on the base and planned recovery weeks that let the gains land.
03Peak3 weeks · Nov 1, 2026 – Nov 21, 2026
The hardest weeks of the plan: race-specific intensity at nearly full training load, sharpening exactly what this race asks for.
04Taper2 weeks · Nov 22, 2026 – Dec 5, 2026
Volume drops while intensity stays: short, sharp efforts keep the legs awake as fatigue drains away.
05Race week1 week · Dec 6, 2026 – Dec 12, 2026
Openers, rest and logistics. The work is done; the job now is arriving fresh.
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