RUNNING METRICS: WHAT EXACTLY IS YOUR RUNNING WATCH TELLING YOU?

For this week’s Coach’s corner I wanted to spend a little bit of time covering a few of the interesting and highly useful data that some running watches provide to us these days. This is intended to be a high-level overview of the various running metrics provided by Garmin (and I’m sure some other brands) beyond just your average pace and course elevation, which we are all accustomed to seeing. Next time I plan to dive a little deeper into each one of these metrics.

Heart Rate

This is one of the best indicators of running effort. As we get older, the maximum heart rate (HR) at which we can run goes down, and knowing how you're training relative to your maximum HR can serve you well. Maximum HR is generally thought of as 220 minus your age. In order to keep it simple, HR is typically divided into zones that correspond to the intensity of the workout, and the higher the zone the higher the intensity (see chart below). An easy run, for example, should not be in zone 5 (Z5) because that would mean your effort during the run is higher than necessary. A recovery run however, such as the one below, can lead to elevated HR because you are essentially running on tired legs and working harder than you normally would at that pace.

For my run above, here were the corresponding HR zones and the time spent in each one.

Here's a breakdown of target HR zones for moderate-to-hard-effort workouts (50-85% effort), as well as maximum HR. This is based on averages, so use it as a general guide.

Cadence

Cadence is the frequency at which your feet land on the ground. Garmin has researched many runners of all different levels and in general, more experienced runners tend to have higher cadence. The optimal cadence for a runner is 180 steps/minute, but higher cadences in general are beneficial because they’re associated with shorter ground contact time, which can translate to less risk of injury.

Here’s a chart that shows how your cadence compares to other runners.

Vertical Ratio

This is one of the most unsung metrics to me because it’s not talked about much but it can be very eye-opening. Vertical ratio is a cost-to-benefit ratio where the cost is the vertical oscillation (ground clearance or lift) and the benefit is the distance travelled (stride length). If, as a runner, you spend more time in the air but are not covering a lot of ground, you may not be running as efficiently as you could. The reverse is also true. If your vertical oscillation is low relative to your stride length (and hence a lower vertical ratio) then you are essentially running more efficiently. Garmin’s research shows that the more experienced and faster runners tend to have lower vertical ratios. Please note that vertical ratio is independent of the runner's height, which makes it easy to compare from one runner to the next.

Ground Contact Time Balance

Don’t let the name fool you. Ground contact time (GCT) balance is a fascinating metric! This is a measurement of the percentage of time each foot spends on the ground while running. Many coaches believe that a symmetrical gait is most desirable for performance and injury prevention. Garmin has researched many runners of all different levels to determine typical ground contact time balance ranges. Also interesting to note,  testing has shown that for many runners, GCT Balance tends to deviate further from 50 - 50 (50% L - 50% R) when running up or down hills. Some runners report that injuries are reflected in their GCT balance which can make it a very important metric to pay attention to in an effort to prevent injuries and ensure your running longevity.

Here’s a chart that shows how your GCT balance compares to other runners.

Overlays

It’s also possible to compare two or more metrics together, by overlaying them, to gain even more insight into your running performance. In the example below, I compare my pace during my recovery run to my HR, and it reveals how my pace affected my effort during that run.

As you can see, knowing your numbers can really benefit you. If your watch records these metrics, great, and if not, maybe it's time for a new one. Either way, learn how to make these metrics work for you and you can become an even better runner.

Run Better. Run Smarter. Run For Life.

Coach Mwangi