100km Ultramarathon Training Plan

Training for a 100km ultramarathon requires more than simply increasing mileage. It requires structure, consistency, and a clear understanding of how to manage fatigue over time.

This 100km ultramarathon training plan developed by Camino Ultra (Camino Ultra) for Stolt Running is designed for runners stepping beyond the marathon distance and preparing for their first — or next — 100km race.

The plan was originally created for the London 100 (London100), a 100km urban ultramarathon. The structure makes it equally suitable for other road-based or urban 100km events, with simple adjustments for terrain or elevation.

This PDF plan is free to download and is suitable for runners with marathon experience who are ready to commit to ultra-distance training.

Inside the PDF you’ll find:

• A week-by-week 100km plan with progressive phases including build, endurance, specificity, peak and taper
• Clear guidance on how to use the plan without chasing perfection
• Practical ideas for staying consistent, including commuter running as a simple way to add mileage
• Simple reflection prompts to help you learn what works for you
• “Toolbox” mindset tips for the moments when training gets challenging

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