NavRun Blog
NavRun Blog
Training craft for ultrarunners. What actually works out there, and why.
Should I Nap During a 100-Miler? The Data Decides
83% of 100-mile finishers skip the nap. Whether you should is a function of one number: your projected finish time. Here's the framework.
Read MoreWasatch Front 100 Prep: Heat, Cold, and the Re-Entry Rule
Wasatch Front 100 starts September 11: 24,000 feet, extreme temperature swings, and a re-entry penalty no other major 100 carries. Cutoff math and prep inside.
Read MoreWhy You Still Feel Flat Weeks After a 100-Miler
New science names the post-ultra flatness that outlasts sore legs: red blood cell damage that scales with distance. What the study found, and what it means for recovery.
Read MoreLeadville 100 Cutoff Times: The Math Behind 30 Hours
The Leadville 100 starts at 4 AM on August 22. Here's the cutoff math: Winfield, Twin Lakes inbound, Mayqueen, and what your training data says about 30 hours.
Read MoreWhy Women Keep Winning Ultras Outright
Fat oxidation, pacing splits, and muscle fiber data explain why ultra distance closes the sex performance gap, and what Entrekin's Cocodona win proves.
Read MoreYour Zone 2 Ceiling Is Wrong — Here's How to Fix It
Your watch computed your zone 2 using a formula with no lab validation. New 2025 research shows the error can reach 15–20 bpm. Here's the 20-minute field test that fixes it.
Read MoreIs Your Chicago Training on Track? The 3-Signal Check
4–6 weeks into fall marathon training? Here's the 3-signal data check, heat-adjusted pace drift, HR creep, and mileage ramp, that tells you if your Chicago goal time still holds.
Read MoreLow HRV During a Training Block: A Diagnostic Guide for Ultra Runners
Before you back off a session, diagnose why HRV is low: training load, degraded sleep, or the feedback loop driving both. A framework for ultra runners.
Read MoreConnect Any AI to Your Running Data
Connect Claude, ChatGPT, or any AI to your NavRun data and ask real questions about your training. Free, read-only, and it never sees your Strava password.
Read MoreHRV Explained: The Daily Training Signal ACWR Misses
HRV answers the daily question ACWR can't: should today's hard session happen? A practical decision framework for runners with Garmin, Whoop, or Oura.
Read MoreUTMB 2026 Training: Vert Targets for the Final 7 Weeks
UTMB 2026 starts August 28. Here are your weekly vert targets for the final 7 weeks, the heat block decision if you're not alpine-based, and the exact taper week.
Read MoreFall Marathon Training in Summer Heat: The Two-Phase Plan
Your fall marathon block is already running in summer heat. Here's the two-phase structure that keeps your training honest through week 16.
Read MoreYour Summer Pace Is a Lie: The Dew-Point Adjustment
Your summer running pace looks terrible, but the algorithm doesn't know it's 78°F with a 68°F dew point. Here's the math that makes your fall marathon training data honest.
Read MoreHeat Acclimation for Runners: Two Paths, One Block
Summer's spiking HR isn't a problem to survive, it's a 10-day stimulus. The science, two protocols (including the 6-day HWI shortcut), and what to watch in your Strava data.
Read MoreBuilding Your Ultra Base: The 12-Week Foundation Phase That Makes Everything Else Work
Accumulated fitness is not the same as a built ultra base. Here's the 5-signal readiness check and a 12-week base-building plan for experienced ultra runners stepping up to longer goals.
Read More40 Miles a Week Is Enough for a 50K (Not a 100)
Training for a 50K or 50-miler on 40 miles a week is achievable -- if you spend those miles in the right order. Here's the allocation framework that actually works.
Read MoreTime on Feet: Why Mileage Fails Ultra Runners
Mileage misleads ultra runners the moment terrain enters the picture. Time-on-feet targets for 50-mile and 100K training -- and how to restructure your week in hours.
Read More100-Mile Training Plan: A 24-Week Phase Breakdown
A structured 24-week training plan for first-time 100-miler runners with ultra experience. Six phases, what each builds, the three decisions that separate finishers from DNFs, and an honest look at the life cost by phase.
Read More50K to 50 Miles: What Changes After Mile 35
You've finished 50Ks. But 50 miles starts a different race after mile 35, one your 50K training never touched. Here's how to close the gap.
Read MoreTraining Paces Explained: The Five Zones and Why Most Miles Should Be Easy
What VDOT is, the five Daniels training zones (Easy, Marathon, Threshold, Interval, Repetition), and how to get all of them from a single recent race.
Read MoreUltra Fueling: How Many Carbs Per Hour Do You Actually Need?
How many carbs, how much fluid, and how much sodium per hour for an ultramarathon, the real ranges, why gut training matters, and how to dial in your own numbers.
Read MoreRace Time Predictor: What One Race Actually Tells You (5K to 100 Miles)
Enter one recent race result and get predicted finish times from 5K to 100 miles. Free, no signup. Here's the math behind it, where it works, and where it lies to you.
Read MoreHow to Use a Pace Calculator (Without Blowing Up Your Race)
Pace is just time divided by distance. Here's how to use a pace calculator to set even splits, why even pacing beats going out hot, and how to turn the number into a race-day plan.
Read MoreUltra Marathon Speed Training (The Missing 15-25 Minutes)
Speed training can improve your ultramarathon finish time by 15-25 minutes without sacrificing durability. Learn which intervals and tempos actually transfer to 50K racing.
Read MoreRunning Tired: Why Consecutive Long Runs Build Ultra Fitness
Learn why running tired on Sunday teaches your body the core demand of a 100-miler. Discover when to add consecutive long runs and how to validate the adaptation in your training data.
Read MoreYour First 50K Training Plan: 12 Weeks to Ready
Build a 50K training plan designed for ultrarunning durability, not speed. Learn the metrics that predict readiness and a proven 12-week training structure.
Read MoreUltra Elevation Data: How to Read Vert
Your watch records elevation gain on every run. Here's how to actually use those numbers to plan ultra training and predict race performance.
Read MoreTraining Splits That Predict Ultra Race Day
Your training splits already know how your ultra will go. Five signals to read in your data, weeks before the start line.
Read MoreWestern States 100 Prep: Canyons, Heat, Field
How to train for Western States 100, canyon climbs, downhill quads, heat acclimation, and pacing the most competitive ultra in North America.
Read More100-Miler Readiness Checklist (Data)
A data-based readiness checklist for your first 100-miler. Use your Strava training metrics to honestly answer: are you actually ready?
Read MoreACWR Explained: Your Watch's Hidden Metric
Your GPS watch calculates ACWR every week but never explains it. Here's how ultra runners actually use training load data to avoid injuries.
Read MoreStrength Training for Ultra Runners
The 9 exercises that prevent injury and build durability for 50K to 100-mile races. Plus a 12-week programming guide for ultra runners.
Read MoreUltra Aid Station Strategy: In and Out Fast
How to handle ultra aid stations in under 5 minutes without underfueling. The pre-arrival checklist, in-station workflow, and downstream bonk math.
Read MoreStrava vs TrainingPeaks vs NavRun: Ultras
Honest comparison of Strava, TrainingPeaks, and NavRun for ultra runners. What works for 100-mile training, what doesn't, and what to use when.
Read MoreUltra Running After 40: The Masters Edge
Why runners over 40 dominate ultras, the science of masters performance, recovery, and how to train as your body changes.
Read MoreUltra Mandatory Gear: Pack Smart, Not Heavy
What ultra runners actually carry vs what stays in the drop bag. A gear-by-gear breakdown of mandatory kit, dead weight, and pack organization.
Read MoreThe Mental Game of Ultra Running
Named mental frameworks ultra runners use when the brain says stop. The pain cave, the 10-minute rule, chunking, mantras, and reframing pain.
Read MoreUltra Race Post-Mortem: Read Your Data
Your ultra race splits, heart rate, and pace data hold the forensic evidence of where you left time. Here's how to read them.
Read MoreBack-to-Back Long Runs: Data Framework
A 6-metric framework to measure if your back-to-back long runs are producing adaptations. Track ultra training effectiveness using Strava data.
Read More5 Weekly Training Numbers for Ultras
The 5 numbers ultra runners should check every Monday. Learn which weekly training metrics actually predict race readiness and injury risk.
Read MoreUltra Recovery Timeline: 50K to 100Mi
Science-based recovery timelines after ultramarathons. How long to rest after a 50K, 50-miler, 100K, or 100-miler, and when to start running again.
Read MoreUltra Overtraining: 7 Warning Signs
Spot overtraining before it sidelines you. Learn the 7 warning signs ultra runners miss and how to monitor training load without guessing.
Read More6 Injury Prevention Habits for Ultras
The 6 daily habits that keep high-mileage ultra runners healthy. Science-backed injury prevention for 50K to 100-mile training.
Read MoreRacing Ultras at Altitude: A Sea Level Guide
How altitude affects ultra performance and a practical prep plan for sea level runners racing above 5,000 feet. Acclimatization, pacing, and fueling tips.
Read MoreReal Food for Ultras: What to Eat
Specific real food options ultra runners use during 50-mile and 100-mile races. Includes what to carry, what to grab at aid stations, and when to eat what.
Read MoreUltra Hydration: Sodium, Sweat, Safety
How much sodium you actually need per hour during an ultra, how to test your sweat rate, and how to avoid hyponatremia. Science-backed hydration guide.
Read MoreGut Training for Ultras: A 12-Week Plan
A week-by-week gut training protocol for ultra runners. Build race-day nutrition tolerance so your stomach cooperates at mile 60.
Read MoreUltra Fueling 101: Calories Per Hour
How to calculate your calorie targets and build a nutrition plan for 50K to 100-mile ultras. Includes a per-hour fueling framework.
Read MoreWhen to DNF an Ultra: A Framework
A clear decision framework for when to drop from an ultramarathon and how to process a DNF without regret. Physical, mental, and contextual factors.
Read MoreHow to Crew and Pace an Ultra Runner
The complete guide to crewing and pacing an ultramarathon. Gear checklists, aid station tactics, night pacing tips, and the mistakes that cost runners hours.
Read MoreSurviving the Night in a 100-Miler
How to train for, gear up, and mentally survive the dark hours of a 100-mile ultramarathon. Practical strategies from sports science and race experience.
Read MorePower Hiking for Ultras: A Guide
Learn power hiking technique, when to hike vs run, and how to train the skill that saves your legs and wins ultramarathons. Free training tips inside.
Read MoreTrail Running for Beginners: Start Here
Road runner going off-road? Learn the gear, technique, and training shifts you need for a safe, fun transition to trail running.
Read MoreHow to Periodize Your Ultra Season
Racing 50Ks, 50-milers, and 100s in one year? Learn how to structure your ultra season with A/B/C race tiers, recovery blocks, and smart periodization.
Read MoreHow to Run a Faster 5K: PR Workouts
Break your 5K PR with proven workouts, race-day execution tips, and a data-driven approach to finding your realistic goal pace.
Read MoreRace Day Pacing: Negative vs. Even Splits
Negative splits, even splits, or positive splits, which pacing strategy leads to a faster race? The science, the tradeoffs, and when to trust the plan.
Read MoreTrail vs Road: Why Your PR Won't Map
Your road PR means nothing on trails. Learn why pace drops 10-20%, how to set realistic trail goals, and why effort matters more than splits.
Read MoreMarathon Taper: Rest Without Losing Fitness
Master the marathon taper: cut mileage correctly, keep intensity, and arrive at the start line fit, fresh, and ready to PR. Week-by-week guide.
Read MoreYour Strava Data Is Missing the Big Picture
Strava tracks your runs, but it won't warn you about injury risk, predict your race time, or build your next training plan. Here's what's missing.
Read MoreHow AI Training Plans Actually Work
What really happens when AI builds your running plan. The data, the logic, the limits -- and what to look for in a good one.
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