A big part of improving your running, and nailing a new PB, comes from your heart — your willingness to embrace the joy, disappointments, and thrills of training. But your head also factors in when you’re aiming to get faster, and paying attention to qualitative stats about your running performance can pay off.

New running smartwatches can help supply those stats. Many gather all kinds of numbers each time you go for an outdoor jog. The latest update to Apple Watch takes measurements like ground contact time and vertical oscillation; running watches from Garmin track these and widgets like Training Status, which combine metrics to give you a glimpse at your overall fitness and whether you’re improving.

“Runners can use many of these objective, data-based features to keep themselves honest,” says Joe Heikes, a runner and product engineer at Garmin. “We all can fool ourselves sometimes if we’re just listening to our bodies and not looking at the numbers; even that being said, stressing about some of the metrics might not be productive, as not every metric has an ideal number to hit.”

“Many of the running mechanics – related metrics are going to be very individual, so there really isn’t an optimal number to target and focusing on ‘improving’ them could actually increase injury risk,” says Jeff Gaudette, owner and head coach at RunnersConnect. Rather than directly trying to improve each metric during your runs, he recommends tracking your stats and noting how they evolve and improve throughout your training.

Here are eight running metrics that new settings on many smartwatches have made easy to track. Read on for more about what they mean and how they may affect your performance.

Understand These 8 Key Running Metrics

Ground Contact Time
This stat is a measure of the amount of time your foot is in contact with the ground with each stride, and it naturally lowers the faster you run. Running with a midfoot strike (rather than landing on your heel) tends to improve this metric by lowering the contact time.

Changing up your form to strike with your forefoot rather than your heel is tricky and not always advised. But, doing exercises that strengthen your glutes and hamstrings can produce more powerful strides and, in turn, improve your ground contact time, says Gaudette.

Ground Contact Time Balance
Ground contact time balance is a comparison of your ground contact times between your left and right foot. It’s usually displayed as a percentage and can help determine if you favour one side of your body over the other or have a limp.

To improve it, add some unilateral strength moves to your routine to work on any strength or flexibility weaknesses that might be causing the disparity.

Stride Length
This straightforward stat measures the distance you cover with each step of your run. “Your stride length will naturally change with pace — getting shorter when you run slower, longer when you run faster,” says Gaudette.

He warns that this isn’t a metric you should try to improve; pushing your stride length could cause you to overstride, which ups your chances of injury. The goal is actually to limit overstriding, keeping your feet more under your centre of mass.

Cadence
If you’re going to use any metric to adjust your running, this would probably be it. Cadence is the number of steps you take in one minute — and unlike most other metrics, this one does have some general numbers that apply to most runners. “Your cadence will change based on your pace, but having too slow of a cadence typically increases your risk of injury,” says Gaudette.

A lower cadence could signal you’re overstriding. If your cadence is lower than 165 steps per minute, try to pick it up. Listening to songs with a higher bpm or practising your arm swing to the beat may help increase your cadence.

Vertical Oscillation
This metric describes how much your torso shifts up and down (in centimetres) with each step while you’re running. Sound random? It is, a little — but it gives you a window into your running efficiency. “Too high of a bounce is inefficient, while too low an oscillation usually means you’re not generating enough power,” explains Gaudette.

While an extreme in one direction or the other isn’t ideal, don’t go changing your form to try to hit a sweet spot for this metric. Instead, Gaudette recommends working some running drills like skips, hops and plyometrics into your weekly routine — they’ll help you improve oscillation and become a more efficient runner.

Vertical Ratio
This number compares your stride length and your vertical oscillation. Generally, the longer your stride, the higher you’re bouncing in the air. The same drills and strength exercises for oscillation should improve this number, too.

Lactate Threshold
You might need to wear a heart-rate monitor along with your watch to track this stat, which measures how efficiently your body can clear lactate while running. Once you know your number, many runners like to use it to dial into the correct heart rate to hit various training goals, says Heikes.

To work on improving your lactate threshold, Gaudette advises adding some tempo workouts to your routine.

VO2 max
Some watches combine several running metrics (like heart rate and pace) to provide this measurement, which tells you the maximum amount of oxygen you’re able to use when running. VO2 max — or as Apple calls it “cardio fitness” — is basically the number-one marker of your overall fitness level. The higher it becomes, the easier your typical workouts feel.

To improve your VO2 max, Gaudette recommends speed workouts like 8×400 metres at your one-kay to 5K pace with one to two minutes rest between.

The Bottom Line on Running Metrics
Even though new watches make it easy to tap a few buttons and tune into all these metrics, keeping tabs on them can be a little overwhelming — especially if you’re not used to it.

“Don’t try to drink the ocean in one gulp,” says Heikes. “Maybe just start by keeping an eye on that VO2 max number as you start getting into shape. If you keep at it and make progress, that number will go up, and that can be quite satisfying.”

At the end of the day, remember that the numbers are just a snapshot of one run or even only a section of that run. “Don’t get too caught up in the numbers,” says Gaudette. “Ninety-five percent of your improvement as a runner is going to come just from running easy, running more, having fun and staying healthy.”

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