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Why You Keep Hitting the Wall at Mile 20—And How to Fix It
Jonah Rosner
February 20, 2025
Why You Keep Hitting the Wall at Mile 20—And How to Fix It
Estimated read time: 3.62 minutes (about as long as my dog Augie's post-long run nap... just kidding, he sleeps for hours 😴)
Hey Performance Nerds! Jonah here. 🤓
Two runners. Same training. Same 3:30 marathon PR. But at mile 20, one surged ahead for a 10-minute PR while the other hit the wall.
What made the difference? Physiological durability—the ability to maintain efficiency under fatigue.
Today's Science Sprint:
Why durability matters more than VO2max 🧬
How elites hold pace while others slow down 💡
What’s happening in your body at mile 20 📊
4 Proven Ways to Build Durability 🏆
What Happens When You Hit the Wall?
Here’s why you keep crumbling in the final miles of your marathon while others power through.
New research from Dr. Andy Jones shows that elite marathoners don’t just start stronger, they stay stronger.
While most runners lose efficiency late in the race, elites maintain lactate threshold, running economy, and coordination. Kind of like a Tesla cruising while a gas-guzzler sputters out.
Translation? Elite runners slow by just roughly 3-5 seconds per mile. Recreational runners drop 15-30 seconds per mile—enough to say goodbye to your marathon PR.
The Truth About Marathon Durability
Durability is what separates finish-line sprinters from late-race zombies.
🔥 Threshold Stability: Elites can hold marathon paces for 2+ hours with minimal drop in their lactate threshold pace, while others decline rapidly—turning marathon pace into an all-out 5K effort.
⚡ Running Efficiency: Fatigue crushes efficiency—elites lose just 2%, while others drop 8%.
✅ VO2 Max Maintenance: Elites barely lose VO2 max over a marathon, allowing them to sustain high intensities longer.
Elite runners stay strong, while others fade like my dog Augie after 5 minutes of chasing his tail. Build durability, or prepare for the doggie struggle shuffle.
🕒 Long-Term Gains: The biggest key to durability? Time.
To resist fatigue like the elites, you must develop key adaptations over years:
More mitochondria 🏃 → Sustained energy.
Stronger muscle fibers 💪 → Better fatigue resistance.
Better fat utilization 🔋 → Preserves glycogen.
Optimized biomechanics 🏃♂️ → Less wasted effort.
4 Proven Ways to Build Durability
1. Fuel Like You Mean It 🍯
Want to hold pace late in the race? Your fueling strategy is everything.
Research shows runners who consume 60g+ of carbs per hour maintain power 18% longer compared to those who don’t:
✅ Preserve threshold & economy
✅ Provide muscles with extra energy
✅ Stabilize blood glucose (less bonking!)
✅ Prevent liver glycogen depletion
✅ Supports neural function (less brain bonk!)
Carbs prevent your power from crashing—unlike Augie, who crashes on the couch after a single zoomie. Fuel up, don’t bonk. #BeBetterThanAugie
🔬 Pro Tip: Use both glucose + fructose to absorb more carbs & boost endurance.
2. Train for Specificity 🎯
The key to durability? Long runs at marathon pace.
Training at marathon pace is the best way to resist late-race slowdown.
💡 Progressive Long Runs:
Start with 8-10 miles with 2-3 at marathon pace
Build to 16-18 miles with 8-10 at marathon pace
Include 2-3 runs of 20+ miles with significant marathon pace segments
Why? Because training long at marathon pace is the best way to resist late-race slowdown. The faster you finish, the sooner you get to post-race ice cream. #Priorities
3. Strength Training = More Durability 🏋️♂️
🚀 Runners who add 2x weekly strength training improve time to exhaustion by 42% after a prolonged run:
💪 What to do:
Heavy lifts (squats, deadlifts) → Maximal strength.
Plyometrics (box jumps, bounding) → Neuromuscular efficiency.
Explosive work (weighted jumps) → Coordination & power.
💡Pro Tip: Strength training reduces the efficiency drop-off that leads to "the wall.”
4. Play the Long Game 📈
The biggest factor in durability? Years of consistent training.
⏳ Think long-term:
✅ Consistency > intensity
✅ Gradually build volume year over year
✅ Train in blocks, not just weekly mileage
✅ Stay healthy to avoid major interruptions
Practical Summary
🍌 Target 60-90g carbs/hour (and practice fueling in training!)
🏃 Progress long runs with marathon-pace segments
💪 Incorporate strength training (2x per week)
📈 Build volume consistently year over year
⏳ Trust the process—durability takes time.
🚨 Science-Backed Way to Use Caffeine For Faster Marathons!
Did you miss my post about How to Use Caffeine to Run Faster? You can find it below!
I won’t lie. These posts take me a while to make. If you find it helpful, share it on your story or with a friend. It helps me a ton!
Are You a True Running Nerd? Prove it.. 🧐
Welcome to the prove you’re a nerd section. Each week, I ask a question about a common running science myth.
Answer correctly, and you’ll be entered into a weekly raffle to win a package of Jonah’s favorite supplements.
What is the ideal protein-to-carb ratio for post-run recovery when you have another hard session the next day? 🏃♂️🍞💪 |
Last Week’s Results: Gut Training 101! 🏃♂️🍯
Well, performance nerds, you absolutely nailed this one! 🎯
The best way to train your gut for marathon fueling is to practice your race-day fueling strategy in training—and a whopping 98% of you got it right! ✅
Here’s how the votes stacked up:
🥯 A. Eat whatever you want—your body will adapt naturally (3)
🍯 B. Follow a structured plan that practices your fueling strategy (232) ✅
🚫 C. Only fuel on race day to avoid stomach issues before then (0)
💧 D. Stick to liquids only—solids are too hard to digest (1)
Why this matters:
Your gut is trainable, just like your muscles. By gradually increasing carb intake during training, you teach your body to tolerate fuel efficiently, reducing the risk of GI distress on race day.
Nerdy Finds of the Week 📚🧑🔬
This section includes my favorite research, podcasts or books about running/lifting science.
📊 How to Adjust Nutrition for Injury Recovery
When you're injured, your muscle loss accelerates due to reduced activity, inflammation, and neural inhibition. But with the right nutrition, you can preserve muscle, reduce inflammation, and set yourself up for a faster recovery.🍎 Injury Nutrition Strategy (Pre-Surgery & Early Recovery)
✅ Protein First (1.6–2.5g/kg/day)
Aim for 20-40g per meal to maintain muscle.
Focus on leucine-rich sources (whey, eggs, fish, soy).
Spread intake evenly throughout the day.
✅ Creatine (5g/day)
Helps preserve muscle and strength even when movement is limited.
Supports energy production for rehab exercises later.
✅ Omega-3s (2-5g/day EPA/DHA)
Reduces inflammation and muscle breakdown.
Found in fatty fish, fish oil supplements, flaxseeds.
✅ Collagen + Vitamin C (10g + 50mg pre-exercise)
Might support tendon, ligament, and cartilage health.
Best taken 30-60 minutes before any rehab exercises.
✅ Don’t Underfuel!
Injuries increase energy needs for tissue repair.
Cutting calories too much can slow healing and increase muscle loss.
🚀 Quick Action Plan
✔ Prioritize high-protein meals at least 4x/day.
✔ Take creatine & omega-3s daily for muscle retention.
✔ Use collagen + vitamin C before movement (even light rehab).
✔ Eat enough calories—injury recovery is not the time to diet!💡 Faster healing starts with better fueling. Adjust your nutrition, protect your muscle, and recover stronger. 🚑💪
Don’t forget: You + Science = AWESOMENESS 😎
Yours in science,
Jonah
P.S. - We have a crew of 15,000+ nerds here who are running FAST using science.
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