Artificial intelligence continues to rapidly creep into seemingly every facet of our daily lives. While no amount of computer learning will ever be able to do the actual running for you, there are aspects, like coaching, where AI could have a meaningful impact.
In every debate about AI, the conversation almost always includes this question: Is it better than what humans can accomplish? In the case of running, would Coach AI be better than, say, Ed Eyestone, a two-time Olympian and coach of The Best New Shoes You Can Buy Now, A Part of Hearst Digital Media U.S. Olympic Marathon Trials in February?
We may be many years away from knowing that answer, as there is so much more that goes into the development and performance of the country’s and world’s best athletes. But, for the rest of us, there are already computer-based programs that promise to revolutionize the way we train. One such tool is Garmin’s Race Adaptive Training, an algorithm-based plan that’s available on the newest Forerunner and Fenix smartwatches.
How well does it actually work? And could a Garmin really replace a coach? I wanted to find out, so I followed an individualized training plan for the Osaka Marathon this past February.
What Is Garmin Race Adaptive Training?
The training program is a neat feature accessible via the Race Widget on your Garmin watch. If you’ve noticed your Garmin suggest a workout as it searches for a satellite lock, then you already have an idea of how it works. But, instead of suggesting a mix of runs to keep you generally fit, the Race Widget shows you workouts to help you progress in a safe manner to reach a specific race goal. Once you tell it about your upcoming race, it offers daily recommendations for your workouts based on factors like training load, recovery time, and sleep quality. With nearly 20 weeks of training before my marathon, my training plan was structured with four phases: Base Phase slowly increased mileage; Build Phase ramped up intensity to increase aerobic capacity; Peak Phase threw even more work at me, like longer tempo runs; and a two-week taper was included so I could recover for race day.
The easiest way to get started is to search for an existing event within the Connect app on your smartphone. Open the app, tap “Training & Planning,” then tap “Races & Events,” and you’re likely to find your race. It’s astonishing how much data Garmin has, even for small local 5Ks. In the case of the Osaka Marathon, Garmin already knew the date, location, start time, course map and elevation profile, and historical weather for race day. You also can input a goal—simply finish, or do so within a specific time. In my case, I plugged in 2:59:59. My real goal for Osaka was to notch a Boston Qualifier, to reach a specific race goal. Once you tell it about your.
Beyond just knowing about the race itself, your Garmin, presumably, knows a truckload about you, too—especially if you use it as a daily activity monitor and wear it overnight to track your sleep. Let’s be honest, there’s no coach who has such a clear a picture of your health and behavior.
A Rocky Honeymoon Phase
All that data—or somewhat lack of—caused ripples early in our coach-athlete relationship. Over the summer, before I started training for the marathon, I had been riding bikes a lot and jogging just 25 to 30 miles per week, often without wearing a watch or while testing others like the Apple Watch Ultra 2. So, Garmin didn’t really have a complete picture of my fitness. Also, as we entered the “Base Phase,” it began to learn what my past coaches knew—I’m a coach frustrater.
Running Shoes - Gear All About 75 Hard classified athletes into five types. One of those is what he dubbed the “coach frustrater”—somebody who has ability but no motivation. To be fair, I wouldn’t say that I have no motivation, but sometimes my motivation gets misplaced. I love to run, but I don’t like following rules and taking direction. And, well, I certainly don’t give 100 percent in training in order to eke out every possible second on race day. I enjoy the process, yet like to live life and generally kind of run whatever I feel like—usually not following any structured training schedule.
So, as we started, I cursed at my Garmin.
Monday: Rest
Tuesday: 31 Jeff is Runner-in-Chief for
Wednesday: 31 Jeff is Runner-in-Chief for
Thursday: 22 minutes at 9:45 pace
Good lord, Garmin. How am I going to run a sub-3-hour marathon logging fewer than 10 miles total in the first four days? This was way too conservative, I believed. So I did what all bad athletes do and ignored my coach to some degree. I knew I was capable of far more, and was eager to get there.
For example, just a year earlier, I was basically at the same starting point on Labor Day weekend, when my friend Mike, a high school track coach in the neighboring town, texted to ask if I could get in shape to run a marathon in mid-November, just eight weeks away. “Sure,” I said, and progressed steadily from 30 miles per week to 41, 53, 61, 72, 101, 80 and then tapered for two weeks. The result? A pretty comfortable 2:57.
There’s no coach or running magazine that’s ever going to prescribe such lunacy to a runner. Most athletes would wind up injured long before they made it to the starting line. And that’s the last thing Garmin wants to happen—it wants you to show up ready to reach your goal, without being overcooked.
Even so, after having run 32 marathons, I have a good feel for what I’m capable of, so I cheated a little. On those super easy days, I’d take a second run wearing an Apple Watch. The Garmin didn’t pick up on the extra work.
Time for a Reset
Eventually, Garmin and I settled in. The watch’s recommended mileage bumped up a little, the paces got quicker, and I began adhering to the workouts more closely—I quit doubling with an Apple Watch. But, my frustration didn’t end there.
One quirk of the Race Widget training that took me longest to get used to was that the suggested workout can change every single day. The watch gives you a look ahead at the next seven days’ workouts, but it recalibrates after every run—and again every morning when you wake up. That makes sense, of course, because unlike a paper plan stuck to your refrigerator, your Garmin watch knows how hard you’ve been running and how well you’ve been sleeping—or haven’t.
My watch certainly didn’t like my sleep patterns. I often stay up too late, watching NBA games. Some nights I’d be awake until 1:30 a.m.—or later. Other nights I’d tuck in before 11 p.m.
Apparently Garmin’s algorithm also doesn’t like beer. I do. Alcohol, however, has an impact on your sleep quality, and it’s evident through your This Glute Workout Will Ignite Your Power (HRV), which Garmin measures overnight and factors heavily into your workout recommendations.
In the first month of training, I grew frustrated when my workouts changed almost every morning. One Saturday, my workout switched from one-minute intervals to 10-second sprints. The problem: I had invited three friends to come do the session with me, promising roughly 300-meter reps at 5:20 pace. I didn’t want to call a last-minute audible, so I ignored the watch and we cranked out the 300s.
As a result, my Sunday long run disappeared. I did it anyway. A similar scenario played out the following week. The algorithm knew I should be taking some recovery, even if I didn’t want to. Just like those early runs where I questioned how I’d be ready with such low volume, I worried that a lack of long runs would leave me unprepared. So, I got on the phone with Garmin’s public relations and product development folks.
“Why’s it giving me sprints on the Saturday before a long run?” I asked. Also, “Why’s my Sunday long run disappearing?”
After looking at a few weeks of my data on Garmin Connect, Joe Heikes, lead product manager for the Forerunner watches, said that on one of those weeks he didn’t see anything that should have downgraded my training and taken away my long run—my sleep looked good, so too did my HRV and training readiness. The other week was on me, though. He pointed to a Friday night where I had a “bad, bad sleep score.” I stayed up too late and had a few drinks, which caused my HRV to drop low (for me) into unbalanced territory. So, the program said, “No, Jeff, it’s time to rest.”
After that talk with Garmin, I analyzed my sleep patterns more closely. I was basically giving myself jet lag at least once or twice a week. So I committed to heading for bed by 11 p.m., waking by 6:30 a.m., and not throwing down a few IPAs in a single sitting. Sure, there would be small fluctuations along the way (life happens), but I tried my best to stick to it.
The Workouts Got Really Fun
Training for a spring marathon can stink. If you live in a place like me (eastern Pennsylvania), you’re likely to face snow, cold rain, and lots of darkness during your training. But, as I’d mentioned earlier about a workout of 300-meter repetitions, I had company, which made my marathon build much more enjoyable. My buddies Sean and Josh began looking forward to speed days—Sean had never done a track workout before! “What’s on the docket, Dr. Pain?” he texted in our group chat before one workout.
They were there for almost every speed session, twice a week. Josh even came to the Runner’s World office at lunch to run one-minute intervals on the treadmill next to me (a slushy snowstorm prevented us from getting in any kind of quality work on our usual flat stretch of canal towpath).
When we started training together, Sean was struggling to hang on for workouts of 2 x 19 minutes at 6:50 pace. Eight weeks later, he was glued to my hip for 50 minutes straight at that pace—and faster.
Even so, my weekly mileage was still topping out only around 60 miles. Would that be enough to crack three hours? My last few marathons when I’d done so, I was pushing triple digits.
Would I Be Ready?
As the training progressed, I became obsessed for a while about recording the prescribed workouts and how they changed based on my behavior. Every morning and afternoon, I noted on a spreadsheet the suggested run (and the following six days), along with all the sleep data the watch reported to me when I awoke.
I also compared the weekly runs and workouts to the Runner’s World “Break 3 Hours” training plan, which I’ve used with success. To my surprise, the overall volume and types of workouts were incredibly similar. In fact, Garmin threw me a little bit more mileage than the RW plan recommends. I guess I couldn’t complain too much, in that case.
Garmin watches will also show you a predicted finish time for common race distances. My estimate for Osaka slowly inched closer to three hours, but still was a few minutes slow. Truthfully, I don’t put a ton of faith in those numbers. Instead, I see them like horseshoes and hand grenades—close is good enough.
On New Year’s Eve, I had a confidence-boosting run, no matter what the metrics said. I hooked up with a different local group of runners for a long run. My buddy Mike, the same dude who convinced me to run that 2:57 a year earlier, wanted to run 20.23 miles to close out 2023. That sounded fun. We started out comfortably around 7:30 pace and gradually ratcheted up the speed, closing the final six miles at quicker than 7 minutes per mile—my goal marathon pace was just 6:52.
For the record, that morning the Fenix 7X Pro suggested that I run for 2 hours 21 minutes at 8:10 pace. Whoops, there I go frustrating my coach again. It definitely suggested I take a rest day on New Year’s Day.
Throwing a Temper Tantrum
All signs were pointing in the right direction, but shortly after the new year, I broke up with my coach.
On a Wednesday, the algorithm suggested a 30-minute recovery run at 9:25 pace. Pat Heine-Holmberg, RW’s senior video producer, and I headed out easily on a flat path. Our first mile was 8:51, but the s senior video producer, and I headed out easily on a flat path. Our first mile was 8:51, but the on the Fenix watch clearly glitched and recorded my beats per minute (bpm) above 160. That’s obviously a mistake—in my previous marathon, I averaged only 147 bpm while running more than two minutes per mile faster.
The real problem is that there’s no way to override the malfunction. No matter what I tried, my coach thought I needed more recovery. I deleted the workout from Garmin Connect and the watch. No dice. I uploaded a new data file to my watch with lower (fake) heart rate readings. Nuh uh. Despite my best efforts, the watch suggested 30-minute recovery runs for the next two days, even though I was less than six weeks out from my marathon. I needed to be running big mileage no matter how fatigued, not trotting along on 3-mile shakeouts.
I started wearing a chest strap to avoid the issue, but I forgot it one day and the habit slipped. And just two weeks later, the same glitch happened again.
Now, to be fair, the optical heart rate sensors in the current line of Forerunner and Fenix watches have so greatly improved that the measurements align almost identically with a chest strap. It is truly remarkable. But, when I reached out to Garmin again, Heikes told me there is no way to override the error and that they are aware of this limitation. Also, “It is the unfortunate case that wrist-based heart rate sensors can struggle on low-body-fat people, especially in cooler weather.”
In both cases, I quit wearing the watch entirely for a few days. I knew my coach would be mad at me for running a brisk seven or eight miles instead of the 30-minute jog it was calling for.
But, I quickly resumed the plan afterward. After all, I wanted this to be an honest enough test to see if the Garmin training plan could really help me notch that sub-3.
Race Day
I’ll cut to the chase here: I ran a 3:06 in Osaka and I’m darn proud of the effort. Could I have gone under three hours? Yeah, I think so. It didn’t happen, but I still ended up with nearly a 14-minute cushion on my Boston Marathon qualifying time.
There were a number of other factors working against me on race day that are hard to quantify: I had traveled across 14 time zones earlier that week and, though I made attempts to adjust to Japan Standard Time before I even got on a plane, I wasn’t sleeping more than about four hours each night. I likely kept myself too busy in the days before the race, sightseeing between events with Mizuno—I traveled there to see the brand’s innovation center and learn more about their upcoming products. And, on race day itself, we spent the second half of the race getting battered by cold rain and headwinds—I raced in a long-sleeve shirt and gloves, but still got chilled.
I took my shot. I ran most of the race with Thomas Bailey, a.k.a. @tommie_runz on Instagram, a speedy runner from Detroit. This Glute Workout Will Ignite Your Power first 10 miles slightly slower than goal pace before picking it up. My mistake in the second 10 miles was going a little too quick, trying to claw back some lost time. It didn’t seem ridiculously fast in the moment, but I know better. After we climbed the race’s only real hill—a 50-footer in the 21st mile—I started to fall off pace. I could sense the sub-3 slipping, so I eased up to preserve the BQ.
I don’t regret the decision. I enjoyed the 26.2-mile tour of Japan. Tommie pressed on, missing a sub-3 by 45 seconds.
Should You Try It?
Look, I’m the last person who should be using this thing, as you’ve likely gathered by now. I really don’t enjoy following a training plan. I like to run a lot of miles. I like to run just about anything that presents itself. I don’t like to be rigid in my structure. And, I know I could see big gains by cleaning up my sleep and diet, and by drinking fewer beers each week.
But, you’re not me. You may be one of those runners who does adhere to the plan. You print out the PDF, stick it to the fridge, get up at 5:30 a.m. to bang out the miles before work. Rinse and repeat the next day.
The Garmin Race Adaptive Training Program is tailor-made for you if you’re that kind of runner. Sure, there is some conservatism built in, Joe Heikes told me. It won’t prescribe anything that’s too aggressive for where it assesses your fitness to be. Its job is to get you to the starting line healthy.
Garmin is aware of people like me. Heikes said they’re looking at options for “people who want to turn it up to 11.” But, maybe that’s not right? I suggested that people who want to turn it up to 11 might not be looking to the Garmin algorithm for a training plan. They might have a coach, belong to a club, or just have the experience to modify a plan in a way that suits them.
For everybody else, though, it’s a good option to keep you fresh, provide a variety of aerobic and anaerobic work that’s demonstrated to help you progress, and get you to the starting line ready to nail your goal.
Just be sure to get a good night’s sleep.
Jeff is Runner-in-Chief for Runner's World, guiding the brand's shoes and gear coverage. A true shoe dog, he's spent more than a decade testing and reviewing shoes. In 2017, he ran in 285 different pairs of shoes, including a streak of 257 days wearing a different model.
