If you're using your sports watch just to track your distance and pace, you're missing out on a huge opportunity to improve your running.
Sports watches are packed with sensors and stats that can turn you into a better, faster and less injury-prone runner – it's just a case of understanding the data and using it to your benefit. But knowing how to interpret all that data can be tricky.
Essential reading: Best GPS running watch
Here are nine clever smartwatch stats and what they mean for your PB.
1. Vertical oscillation
Watch any professional runner in action and you'll notice that there's very little movement in their upper body. Their top half glides swan-like while their legs do all the work under the surface. One measure of this optimum running efficiency is called vertical oscillation and shows the degree of 'bounce' in your running motion.
This bounce is measured in centimetres from a fixed point on your body (in the case of GPS running watches this tends to be a sensor built into the heart rate chest-strap. Typical oscillation is between 6 and 13 cm with the Paula Radcliffe's of this world moving at the lower end of that scale.
Best running watch to buy: The Garmin Forerunner 630 offers real-time vertical oscillation stats.
Cadence or foot strike rate is the number of steps per minute (SPM) you take. It's a vital stat for assessing the efficiency of your running form and thankfully is something that's relatively easy to improve once you're aware of it.
Just like vertical oscillation, some running watches will use sensors in a heart rate chest strap to fire a SPM figure to your wrist, while older generations tend to pair up with a shoe pod.
Full verdict: Check out our Polar M400 review
A typical cadence is between 150 - 200 steps per minute but experts put 180 SPM as the sweet spot for optimum running efficiency for reasons best left to the physicists to explain. A great way to work on your cadence is to find a 180BPM soundtrack for a shorter run and use the beats to quicken your strike rate.
Best running watch to buy: Moov Now is worn on the foot to track cadence effectively.
3. HR Max
Maximum heat rate (HR Max) is the highest number of times your dicky ticker will beat in a minute when you're going all out at your most intense work out level. Your HR Max is unique and depends on your genes and how old you are. The longer in the tooth, the lower your HR Max.
Why is it important? Your maximum heart rate dictates the ranges for all the other zones in heart rate training. The more accurately you know your HR Max, the more accurate your sport zones, and accurate sport zones equal more effective workouts.
There are a number of methods for calculating your HR Max. The most accurate is in a lab, another is using the formula 220 – AGE. In most cases you can manually add your stats into your running watch or they'll also estimate your HR Max based on a fitness test or even a recent workout
So can your improve your heart rate max? In a word, no. Training has little or no impact.
Best running watch to buy: The TomTom Spark offers accurate heart rate data straight from the wrist.
4. Basal Metabolic Rate (BMR)
Like a lot of stats your running watch offers up, the best
way to find your Basal Metabolic Rate, or the number of calories your burn by
just being alive, is to get in a lab with a gas exchange masked strapped to
your face. But in lieu of these expensive tests, we're now seeing some watches
offer up estimates based on the vital info you supply at set up, such as age,
weight and height.
Knowing how much energy your body burns in a given day when you're at rest is really useful if you're looking to get lean or just working out how much you need to eat to stay well fuelled for your training regime.
Best running watch to buy: The Polar V800 breaks down your daily calorie burn into how much your burn with BMR, Activity and Training.
5. Heart Rate Zones
Using your HR Max, different running watches break down your heart rate zones or 'sport zones' into segments and make them easy to understand with different names or colour coding.
Different devices give them different labels but they break down like this: Recovery training (60% of MHR), endurance base training (65-70% of MHR), aerobic capacity training (75-82% MHR), anaerobic threshold training (82-89% MHR) and maximum aerobic training (89-94% of MHR).
It's worth noting that everyone burns fat, rather than carbs, as a main fuel source at different heart rate levels but having your heart rate zones estimated gives you a far better shot at getting the workout effect you really want to achieve.
Best running watch to buy: Garmin Forerunner 630, Adidas miCoach SmartRun, TomTom Spark, Polar V800.
6. VO2 Max
VO2 max sounds like some kind of complicated chemical compound from a school chemistry lesson but it's actually the maximum volume of oxygen (in millilitres) you can consume per minute per kilogram of body weight at max performance. In layman's terms it's a measure of your aerobic capability.
Just like HR Max, the most accurate way to find out your VO2 max is under lab conditions using expensive gas exchange equipment but many of the best running watches now use intelligent algorithms to estimate your VO2 max based on your vital stats and recent workout performance.
Unlike your HR Max, you can train to improve your VO2 max.
Best running watch to buy: Garmin Forerunner 630, Polar V800
7. Orthostatic Test
An orthostatic test measures your heart rate for a period while at rest, before doing the same for a period while you're standing up. From this you get peak heart rate, standing heart rate and resting hear results which can be used to benchmark your overall condition and how ready to you are to get back out and train.
If your resting heart rate is 10 or more BPM above your average – a sign of overtraining - then you can consider resting.
Best running watch to buy: Polar V800
8. Ground Contact
Another smart stat you can use to improve your form if you've got a Garmin Forerunner 620 up your sleeve, Ground Contact time is the amount of time during your running that your foot is on the ground rather then flying through the air.
Measured in milliseconds, a typical runner will have a ground contact time that falls somewhere in the 160 — 300 milliseconds range. Talented types like Mo Farrah and the Geoffrey Mutai spend about 190-milliseconds in contact with the ground each step.
Best running watch to buy: Moov Now
9. Excess post-exercice oxygen consumption (EPOC)
Now we're getting deep into the science. Excess Post-exercise Oxygen Consumption, or EPOC, is the measure of the boost in metabolism (calories and fat burning) your body gets after a workout. Sometimes also know as afterburn.
We all know that when we pound the pavements or bench our own bodyweight, we burn calories to fuel our muscles, but when we're done, we keep on burning, firing and flaying more fat than we would normally at rest. It's all down to what our bodies need to recover from the hard work they've just done.
Some Suunto running watches offer predicted EPOC as a great way to measure the training load of high intensity exercise. Keeping an eye on this number in real time helps quantify the exertion of a training session, giving you the option to stop once you hit an EPOC number.
Tracking EPOC over time also lets you build a good picture of which sessions you personally find more demanding and plan your recovery of training accordingly.
Best running watch to buy: Suunto Ambit Sapphire 2
Enjoy that? Check out our guide on using your GPS running watch to become a better, faster runner.