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Training, racing and recovery for runners, from the HealthAI running library.
Running · Product 01
Notes from our AI running coaches
The physiology and the decisions behind each part of a training plan, organized by the question you are trying to answer.
The AI running coach
How an AI running coach builds and changes your plan, who it is for, and how it compares.
November 3, 2026 · 6 min read
AI Running Coach: How It Works and Who It's For
An AI running coach builds your plan from your own training and changes it as you run. How HealthAI's six coaches work, who they're for and what they cost.
November 3, 2026 · 5 min read
AI Running Coach vs Human Coach: An Honest Comparison
What a great human coach does that AI cannot, where an AI running coach is strong, how costs compare, and how the two can work together on a team.
November 3, 2026 · 5 min read
Best Running Coach Apps for Competitive Runners (2026)
An honest 2026 look at Runna, TrainingPeaks, Garmin Coach, COROS plans, Final Surge and HealthAI: who each suits, how plans adapt, and what each costs.
November 3, 2026 · 5 min read
AI Running Coach for College Runners
How college runners can use an AI running coach alongside a team coach: understand the plan, log and check in, ask better questions, and handle breaks.
November 3, 2026 · 4 min read
AI Coach for High School Runners: A Guide for Parents
Should your high school runner use an AI running coach? What it can do, the risks for young runners, how HealthAI protects under-18s and what to ask first.
October 4, 2026 · 1 min read
Missed a Workout? Don't Make It Up
Doubling up after a missed or failed session is one of the most common training mistakes. Here is how to handle missed workouts, workouts that fall apart, and why consistency beats repayment.
Training plans by event
From the 800 meters to the marathon: what each event demands and how to build a season for it.
November 3, 2026 · 6 min read
Running Training Plans by Event: 800m to Marathon
How training changes from the 800m to the marathon: the balance of speed, aerobic and threshold work, how a season is built, and why one template fails.
November 3, 2026 · 5 min read
800m Training Plan for Competitive Runners
How to train for the 800m: the aerobic and speed balance, speed-type vs endurance-type runners, and sample weeks for base, bridge, specific and taper.
November 3, 2026 · 5 min read
How to Run a Sub-4 Mile (or Sub-5 for Women)
What a sub-4 or sub-5 mile takes: the lap math, the aerobic base behind it, key sessions, a realistic progression and how to race the four laps.
November 3, 2026 · 5 min read
5K Training Plan: How to Break 15 Minutes
The sub-15 5K: pace math (3:00 per km, about 4:50 per mile), the volume behind it, threshold and VO2 max sessions, and a sample 12-week build.
November 3, 2026 · 5 min read
10K Training Plan for Advanced Runners
An advanced 10K plan: why threshold carries the race, the key session types, a sample week for base, threshold, specific and taper, and how to pace it.
November 3, 2026 · 5 min read
Half Marathon Training Plan for Advanced Runners
An advanced half marathon plan: threshold and long run emphasis, fueling for a 60 to 90+ minute race, sample weeks by phase, the taper and race pacing.
November 3, 2026 · 5 min read
Marathon Training Plan for Experienced Runners
A marathon plan for experienced runners: long runs, marathon-pace work, carbohydrate fueling research, sample weeks by phase, the taper and even pacing.
November 3, 2026 · 5 min read
High School Cross Country Training: Summer to State
A safe summer-to-state plan for high school cross country runners and parents: gradual easy miles, rest days, sleep, eating enough, and the coach's role.
November 3, 2026 · 5 min read
How Many Miles a Week Should a Competitive Runner Run?
There is no single right mileage. How weekly volume depends on event, history and recovery, why easy miles are the base, and what injury research shows.
October 3, 2026 · 3 min read
Is the 10% Rule for Running Mileage Real? What Actually Matters When You Build Volume
The 10% rule is the most repeated mileage guideline in running, and the least useful. Here is why a fixed percentage fails, and how to build volume you can actually hold.
October 4, 2026 · 2 min read
Your Long Run Doesn't Need to Be 20% of Your Weekly Mileage
The long run is not a fixed slice of your week. Its length and structure should come from your event, your phase, and what the run is meant to build. Here is how to set it properly.
October 4, 2026 · 2 min read
Are You a Speed Type or an Endurance Type Runner? How to Tell, and Why It Matters
Two runners with the same 5K time can need completely different training. Here is how to identify whether you are speed oriented or endurance oriented, and how that should change threshold work, intervals, easy pace, and your taper.
The science of running workouts
Easy runs, threshold, intervals, strides and hills: what each session builds and how to dose it.
November 3, 2026 · 6 min read
Running Workouts Explained: The Science Behind Each Session
Easy runs, long runs, threshold, VO2 max intervals, strides and hills: what each running workout builds, and how they fit together in a week.
November 3, 2026 · 5 min read
Threshold Runs: What They Are and How Fast to Run Them
Threshold runs train the fastest pace you can hold steadily. How to estimate threshold effort, common session structures, and why controlled beats hard.
November 3, 2026 · 5 min read
Tempo vs Threshold vs Intervals: What's the Difference?
Tempo runs, threshold sessions and intervals overlap but train different things. Clear definitions, where they blur, and when each one fits your training.
November 3, 2026 · 5 min read
VO2 Max for Runners: What It Is and How to Raise It
VO2 max is the most oxygen your body can use. What it measures, how trainable it is, how much it predicts race times, and what interval research shows.
November 3, 2026 · 4 min read
Strides: Why Every Distance Runner Should Do Them
Strides are short, relaxed accelerations that keep distance runners fast and smooth. How to run them, how often, and the neuromuscular reasons they work.
October 4, 2026 · 2 min read
The 80/20 Rule in Running Isn't a Law. Here's What It Actually Means
80/20 training started as an observation about how good endurance athletes train, not a rule to obey by the minute. Here is what it gets right, where it misleads, and how intensity should really be distributed.
October 4, 2026 · 2 min read
Zone 2 Isn't Magic. What Low-Intensity Running Actually Builds
Zone 2 training is useful, but it is not a precise biological switch. Here is what easy running really does, why zone boundaries are approximate, and how to use low intensity without obsessing over a heart-rate band.
October 4, 2026 · 2 min read
Your Lactate Threshold Is a Range, Not a Number on Your Watch
Lactate threshold is one of the most useful ideas in endurance training and one of the most misused. Here is what threshold really is, why a single pace or heart rate misleads, and how to build it safely.
October 4, 2026 · 2 min read
Double Threshold Training: Who It's For, and Who Isn't Ready
Double threshold has become the most copied training method in distance running. Here is how it actually works, why it fails when copied directly, and the steps to take before trying it.
October 4, 2026 · 2 min read
Feeling Destroyed Isn't Proof a Workout Worked
The best runners rarely leave workouts wrecked. Here is why most hard sessions should end with one rep in reserve, what even splits tell you, and when going to the well is actually worth it.
October 4, 2026 · 2 min read
Why Hill Sprints Belong in Week One of Your Training Plan
Short hill sprints build speed, strength, and running economy at almost no recovery cost. Here is exactly how to do them, why they are not an interval workout, and how they protect your speed during high-volume training.
Training by recovery
Sleep, HRV, resting heart rate, fueling and cold: how to read recovery and when to change the day.
November 3, 2026 · 7 min read
Training by Recovery: How Runners Should Use HRV and Sleep
Recovery is how well you absorb training. Learn how sleep, HRV, resting heart rate and how you feel should shape hard days, and why trends matter most.
November 3, 2026 · 5 min read
HRV for Runners: What It Means and How to Train With It
HRV is useful for runners only against your own baseline. Learn how rolling averages, daily noise and HRV-guided training research should shape hard days.
November 3, 2026 · 5 min read
WHOOP Recovery Score for Runners: What to Do in the Red
A red WHOOP Recovery score is a prompt to look closer, not an order to rest. Here is how a competitive runner can use green, yellow and red days well.
November 3, 2026 · 4 min read
Garmin Training Readiness, Explained for Runners
Garmin Training Readiness blends sleep, recovery time, HRV status, load and stress into a 1 to 100 score. Here is how a runner should actually use it.
November 3, 2026 · 5 min read
Should You Run a Hard Workout on a Low Recovery Day?
A low recovery day need not mean no workout. Use this framework to decide whether to swap the session, shorten it, or keep it with a rep in reserve.
November 3, 2026 · 5 min read
Resting Heart Rate and Overtraining: Warning Signs
What resting heart rate can and cannot tell runners about overtraining, how overreaching differs from overtraining syndrome, and warning signs to watch.
October 4, 2026 · 1 min read
When Do Runners Actually Need Fuel? Gels, Hydration, and Training Your Gut
You do not need a gel on a 40-minute run, but you do need a plan for runs approaching two hours. Here is when fueling actually matters, how to hydrate without overdrinking, and how to train your gut for race day.
October 4, 2026 · 1 min read
Running Cramps Probably Aren't About Salt
Electrolytes are sold as the cure for muscle cramps, but cramping is more closely tied to neuromuscular fatigue. Here is what that means for prevention, and where sodium still matters.
October 4, 2026 · 1 min read
Do Ice Baths Help Runners Recover? When Cold Can Cost You Adaptation
Ice baths feel like recovery, but using them right after training can blunt some of the adaptation you trained for. Here is how to time them, what cooldowns really do, and how to match recovery to the actual problem.
NCAA cross country
The 2026 rankings, how the ratings work, and the young Americans to watch.
November 3, 2026 · 4 min read
NCAA Cross Country Rankings 2026, Explained
Who leads the 2026 NCAA Division I cross country rankings, how the USTFCCCA XCRI ratings work, and the young Americans on HealthAI's own ranking list.
November 3, 2026 · 5 min read
How the XCRI Cross Country Rankings Work, Explained
XCRI gives each NCAA cross country runner one rating adjusted for course and conditions. Here is how the scale, uncertainty, tiers and tie-breaks work.
November 3, 2026 · 5 min read
Best American Freshmen in NCAA Cross Country 2026
The 11 freshmen on HealthAI's 2026 NCAA cross country rankings, led by Indiana's Katy Zang at XCRI #5, with best races and why freshman ratings move.