Last week, my new Garmin Forerunner 970 alerted me that I likely shouldn’t run as I was nearing my weekly running capacity. Instead, I experienced firsthand the consequences of disregarding Garmin’s algorithm.
I spent May in a slight running slump, with my mileage dropping around 40 miles from my monthly average. Therefore, I decided to bounce back in June with increased steps and miles. I began with a half marathon while wearing Ray-Ban Metas on June 1, and then I opted to join a local running group for another challenging, hilly run on Global Running Day.
By the completion of my 7-mile run, I had fallen behind the group and felt physically drained with a tight right hamstring. Later, I checked my watch and discovered I was just above my body’s running capacity.
Desperate to revitalize my fitness routine, I went for a low-aerobic jog a few days later once my training readiness score had improved a bit. This turned out to be a mistake: although my heart and lungs felt fine, my hamstring nearly gave out on me. I ended up limping home. After a week of recovery and a busy travel week at an XR convention, I found myself back where I began.
This experience taught me two things: Garmin’s running capacity estimate is valid, and I sincerely hope it doesn’t remain exclusive to Garmin’s $750 running watch like other “premium” features.
How Garmin Running Capacity functions
Garmin states that Running Capacity assists you in “identifying potentially risky training patterns” and “intelligently managing the effects of running on your body as you aim to build and sustain mileage.”
It builds on acute load, which refers to the training load’s effect on your body from the last seven days of workouts, which most Garmin Forerunner models monitor. However, this metric emphasizes excess post-exercise oxygen consumption (EPOC), instead of biomechanical load.
This is where Running Capacity alters the approach. For each run, it considers your weight, speed, intensity, ground contact time, cadence, and significant inclines and declines, among other factors.
The aim is to measure the “force exerted by the ground on your body.” A rapid downhill run, for instance, might be “three times more strenuous than an easy run on flat terrain.” You might not typically notice this since the run felt easy on your lungs.
Garmin then evaluates your acute impact load miles against your running capacity, based on your recent running background. It alerts you if you’ve entered a “cautionary state” where you should be careful of potential injury or burnout.
This is distinct from Garmin’s standard post-run recovery estimate, as it takes more than just your cardiovascular system into consideration. This context is crucial for runners!
Naturally, most semi-serious runners will display better self-control than I did and halt when their body signals to stop. Nonetheless, running capacity remains essential context for anyone aiming to elevate their training.
Beginner runners require this more than veterans
Garmin’s entire wearable strategy involves locking software features, such as how the Forerunner 970 provides offline maps but the 570 doesn’t, or how the Forerunner 165 utilizes training load data in the background to suggest daily workouts but restricts you from viewing the widget. It requires additional payment for the best tools.
And fine, if Garmin wants to restrict maps, real-time stamina, Strava Live Segments, and endurance scores to premium models like the 970 and Fenix 8, we just have to accept it.
However, running capacity is intended to prevent injuries by warning individuals who are unaware of their limits. I would argue that it’s especially crucial for couch-to-5K runners or casual runners who could seriously injure themselves to understand how the impact of a run may not correspond directly to the number of miles they’ve run.
Are casual runners likely to spend $750 on a running watch? No, and they shouldn’t! Not until they’re proficient enough to fully utilize the features. But running capacity doesn’t seem “advanced” to me; it feels essential.
I shouldn’t have disregarded my running capacity data, but at least I was warned in advance. Other Garmin watch users lack that context. So while I find it improbable based on Garmin’s history, I’m hopeful that Garmin’s running capacity will eventually extend to more watches and assist people in avoiding injuries!
