100K Ultra Marathon Training Plan

How to Use This Training Plan

Getting Started

This 20-week program is designed for experienced ultrarunners ready to tackle the demanding 100K distance. This is not an entry-level ultra plan—it requires significant running experience, mental fortitude, and the ability to manage high training volumes while balancing life responsibilities.

Before You Begin:

• Verify you meet all prerequisites—minimum 50 km weekly base for 3+ months and marathon completion experience
• Get comprehensive medical clearance, especially if you have any cardiovascular or musculoskeletal concerns
• Secure support from family/friends—this training requires significant time commitment
• Invest in quality trail running shoes (if racing trails) and replace them every 500-600 km
• Develop and test a nutrition and hydration strategy that works for your system
• Consider hiring a coach or joining an ultra running group for support and accountability

Understanding the Structure

This plan uses a 4-phase periodized approach spanning 20 weeks:

1. Base Phase (Weeks 1-6): Build aerobic foundation and weekly volume tolerance
2. Build Phase (Weeks 7-10): Introduce back-to-back long runs and progressive overload
3. Peak Phase (Weeks 11-16): Highest training stress with ultra-long runs up to 60 km
4. Taper Phase (Weeks 17-20): Reduce volume while maintaining intensity, allowing recovery and peak performance

Key Training Components:

• Easy Runs: Conversational pace (60-70% max HR)—the foundation of ultra endurance
• Medium Runs: Moderate effort (70-75% max HR) that bridges easy and tempo pace
• Tempo Runs: Sustained threshold efforts at 80-85% max HR (marathon pace)
• Hill Repeats: Uphill efforts to build strength, power, and climbing efficiency
• Long Runs: Progressive weekend sessions, eventually reaching 60 km
• Back-to-Back Long Runs: Consecutive day long efforts (Tuesday + Saturday) to simulate race fatigue
• Recovery Runs: Very easy efforts for active recovery between hard sessions
• Strength Work: Core, hip, and glute exercises 2x weekly

Your Weekly Schedule

Training follows a undulating periodization with systematic increases in volume followed by consolidation weeks. High-volume weeks (especially weeks 11-16) require careful planning around work and family commitments.

Typical Weekly Structure:

• Monday: Easy run + strength work
• Tuesday: Back-to-back long run or quality workout (tempo/intervals/hills)
• Wednesday: Rest or active recovery (cross-training, yoga, swimming)
• Thursday: Quality session or medium run
• Friday: Easy run + optional strides
• Saturday: Long run (primary weekly session)
• Sunday: Recovery run or complete rest

Time Commitment:

• Base phase: 8-12 hours per week
• Build phase: 12-15 hours per week
• Peak phase: 15-20 hours per week
• Taper phase: 6-10 hours per week

Pace and Intensity Guidelines

Easy Runs (60-70% max HR):

• Truly conversational pace—full sentences with no breathlessness
• Should feel effortless and sustainable indefinitely
• These comprise 70-80% of your total training volume
• Running too fast on easy days is the #1 mistake in ultra training

Medium Runs (70-75% max HR):

• Comfortable but focused effort
• Can speak in phrases but wouldn't want to have a long conversation
• Aerobic development without excessive fatigue
• Bridges easy and tempo efforts

Tempo Runs (80-85% max HR):

• "Comfortably hard" sustained effort around marathon pace
• Can speak a few words but breathing is heavy
• Improves lactate threshold and race pace confidence
• Should feel challenging but controlled

Hill Repeats:

• Hard uphill efforts at 85-90% max HR
• Focus on form (forward lean, powerful push-off, relaxed shoulders)
• Builds strength and power without impact stress
• Walk or jog down for recovery between repeats

Long Runs:

• Start at easy pace; may progress to moderate effort in final stages
• Primary goal is time on feet and mental endurance
• Practice all race-day nutrition and gear
• Should feel tired but not destroyed afterward

What to Expect Each Phase

Phase 1: Base Building (Weeks 1-6)

• Establishing aerobic foundation and weekly training rhythm
• Long runs progress from 30 km to 40 km
• Introduction to consistent weekly structure
• Getting comfortable with 5-6 sessions per week
• Body adapts to sustained training load

Phase 2: Build Phase (Weeks 7-10)

• Introduction of back-to-back long runs (Tuesday + Saturday)
• Long run distances reach 42-45 km
• Increased training stress—prioritize recovery
• Week 10 includes first marathon-distance run
• Mental and physical adaptation to ultra volumes

Phase 3: Peak Phase (Weeks 11-16)

• Highest training stress of the entire plan
• Back-to-back long runs become regular weekly feature
• Ultra-long runs of 50-60 km in weeks 15-16
• Peak weekly volumes of 150+ km
• Greatest demands on time, energy, and recovery
• This phase makes or breaks race-day performance

Phase 4: Taper Phase (Weeks 17-20)

• Systematic volume reduction while maintaining intensity
• Body consolidates fitness and repairs accumulated fatigue
• Mental freshness returns; confidence builds
• Resist temptation to add extra training
• Trust the work you've done
• Week 20 is race week—final preparation and race execution

Common Challenges and Solutions

"The back-to-back long runs are destroying me"

• Keep Tuesday's effort moderate—not a race-pace hammering
• Sunday recovery run should be genuinely easy or take complete rest
• Prioritize nutrition and sleep between consecutive long efforts
• If consistently struggling, extend recovery between back-to-backs
• Consider substituting one back-to-back session with cross-training

"I can't recover adequately between sessions"

• Check your easy pace—likely running too fast
• Increase sleep to 8-9 hours per night during high-volume phases
• Monitor resting heart rate; elevated HR indicates insufficient recovery
• Add complete rest days instead of recovery runs if needed
• Reduce intensity on quality sessions if fatigue is chronic

"The time commitment is overwhelming"

• Train early morning or use lunch breaks for shorter sessions
• Combine commuting with running when possible
• Communicate training demands with family/employer in advance
• Meal prep on weekends to save weekday time
• Accept that life balance during peak phase is challenging

"I miss multiple sessions or a full week"

• Missing 1-3 individual sessions: continue with planned progression
• Missing 4-7 days: repeat previous week before advancing
• Missing 7-14 days: go back 2 weeks in plan
• Missing 14+ days: consider postponing race or significantly modifying plan
• Never try to "catch up" missed long runs—injury risk skyrockets

"Should I train through minor injuries or discomfort?"

• General muscle soreness: proceed with reduced intensity
• Persistent pain in same area for 3+ days: take rest and assess
• Sharp pain or significant limp: stop immediately and get professional evaluation
• When in doubt, take an extra rest day—better safe than injured
• Consider consulting sports physio proactively during high-volume phases

Essential Tips for Success

Nutrition Strategy

• Practice race nutrition on every run over 90 minutes
• Target 40-60g carbohydrates per hour during long efforts
• Test multiple products: gels, chews, bars, real food (sandwiches, potatoes, fruit)
• Use electrolyte drinks containing sodium, potassium, magnesium
• Develop a feeding schedule (e.g., every 30-45 minutes)
• Practice stomach tolerance at various effort levels
• Never, ever try new nutrition on race day

Hydration Protocol

• Drink to thirst—overhydration is as dangerous as dehydration
• Consume 400-800ml fluid per hour depending on conditions
• Use electrolyte drinks for runs over 90 minutes
• Weigh yourself before/after long runs to gauge fluid loss
• Practice carrying hydration (handheld bottle, vest, waist belt)
• Account for weather—adjust intake for heat and humidity

Recovery Strategies

• Sleep: 7-9 hours nightly; 8-10 hours during peak phase
• Nutrition: Refuel within 30 minutes post-run (carbs + protein)
• Active Recovery: Easy cross-training, swimming, cycling on rest days
• Massage/Bodywork: Weekly or biweekly during high-volume phases
• Compression: Use compression socks post-long runs
• Ice Baths: Optional but effective for managing inflammation
• Monitor: Track resting heart rate, sleep quality, mood, energy

Strength and Conditioning Include 2x weekly sessions (30-40 minutes) focusing on:

• Core: Planks, side planks, dead bugs, bird dogs, Russian twists
• Hips: Clamshells, side leg raises, fire hydrants, hip bridges
• Glutes: Squats, single-leg deadlifts, monster walks, step-ups
• Calves: Calf raises (straight and bent knee), eccentric work
• Mobility: Hip flexor stretches, hamstring stretches, foam rolling
• Schedule strength work after easy runs, not before hard sessions

Gear Essentials

• Shoes: Rotate 2-3 pairs; replace every 500-600 km
• Race Day Shoes: Break in well before race (100+ km)
• Trail Practice: If racing trails, train on similar terrain regularly
• Hydration System: Vest or handheld bottles—test extensively
• Anti-Chafe: Apply liberally on long runs; test products
• Clothing: Test all race-day clothing on long runs
• Headlamp: If race includes night running, practice with it
• Trekking Poles: If permitted and race has elevation, practice using them

Mental Preparation

• Practice breaking ultra distance into manageable segments
• Develop mantras and mental strategies for low moments
• Visualize successfully handling race challenges
• Accept that suffering is part of ultra running
• Prepare strategy for when (not if) things go wrong
• Study the race course, elevation profile, aid stations, cutoffs
• Join ultra running communities for support and shared experience

Tracking Your Progress

Maintain detailed training logs including:

• Each Session: Date, distance, time, pace, elevation
• Physiological Data: Average/max heart rate, RPE (1-10 scale)
• Environmental: Weather, temperature, terrain type
• Nutrition: Food/fluid consumed during and after run
• Subjective Feelings: Energy level, motivation, mood
• Recovery Markers: Sleep hours/quality, resting heart rate
• Musculoskeletal: Any aches, pains, or concerns
• Weekly Volume: Total distance and time per week

This comprehensive data helps identify patterns, prevent overtraining, and optimize your approach.

Race Week Strategy

Week 20 Daily Breakdown:

• Monday: Easy 10 km—stay loose, practice hydration
• Tuesday: Easy 8 km + strides—maintain leg sharpness
• Wednesday: Complete rest—conserve energy
• Thursday: Easy 6 km—final movement session
• Friday: Complete rest—stay off feet, hydrate, eat well
• Saturday: Easy 5 km jog—final shakeout, test gear
• Sunday: RACE DAY

Final Week Priorities:

• Sleep 8-10 hours per night
• Stay hydrated throughout each day
• Eat familiar, easily digestible foods
• Avoid alcohol and limit caffeine
• Stay off feet as much as possible (minimize standing/walking)
• Pack race gear and check twice
• Study course, aid stations, cutoff times, weather forecast
• Prepare drop bags (if applicable) with changes of shoes, clothes, nutrition
• Trust your training—the work is done

Race Day Execution:

• Start Conservatively: First 20-30 km should feel ridiculously easy
• Pace by Effort: Don't fixate on pace—terrain and conditions vary
• Use Aid Stations: Don't rush through them; fuel and hydrate properly
• Break Distance Down: Focus on getting to next aid station, not finish line
• Manage Low Moments: They will pass—keep moving forward
• Expect the Unexpected: Have backup plans for nutrition, blisters, stomach issues
• Stay Present: Don't obsess about remaining distance
• Finish Strong: You've trained 20 weeks for this—savor every moment

After Completing the Program

Immediate Post-Race (Days 1-7):

• Avoid running completely for at least 5-7 days
• Focus on gentle movement: walking, easy swimming, stretching
• Sleep as much as possible—your body is repairing significant damage
• Eat nutrient-dense foods to support recovery
• Expect emotional ups and downs—post-race blues are real

Early Recovery (Weeks 2-4):

• Gradually reintroduce very easy running (start with 20-30 minutes)
• No structured training—just gentle movement and enjoyment
• Continue prioritizing sleep and nutrition
• Consider massage or physical therapy if any lingering issues
• Reflect on your race and training: what worked, what didn't

Rebuilding (Weeks 5-8):

• Slowly rebuild base mileage (increase by 10-15% per week)
• Focus on easy running only—no intensity or long runs yet
• Reintroduce strength and mobility work
• Allow your body to fully recover—rushing back causes injury

Future Planning:

1. Reflect: Thoroughly review training log and race experience
2. Recover: Full recovery from 100K takes 6-8 weeks minimum
3. Rebuild: Return to base training over 2-3 months
4. Plan: Decide next goal—another 100K, first 100-miler, or different challenge
5. Grow: Apply lessons learned to future training cycles

Remember: Completing a 100K ultramarathon is an extraordinary achievement that only a tiny fraction of runners ever accomplish. The training journey is as valuable as race day itself. Trust the process, respect the distance, listen to your body, embrace the challenges, and celebrate your incredible resilience. You're capable of far more than you imagine.