GymKit tested: Everything you need to know about Apple GymKit

watchOS 4 landed on the Apple Watch and with it came something called GymKit. This brand new fitness-focused feature is all about taking your Apple Watch, whether that's a Series 2 or the new Apple Watch Series 3 and making it work with equipment in the gym.

Using NFC, you can tap your Apple Watch to compatible pieces of gym equipment, and start sharing a whole bunch of information between the two devices, which will supercharge the detail recorded from accurate look at your workouts.

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So what equipment will it work on at the gym? When will gyms receive these equipment? What information is being shared? Come, my gym-loving friends, let's find out together as we tell you what Apple GymKit is all about.

GymKit explained

So this is how GymKit is going to work: cardio equipment inside gyms and fitness clubs will start being equipped with NFC readers and GymKit software, which will enable them to pair with Apple Watch.

When you tap your Apple Watch to the NFC reader on the machine, the two will start syncing data, with the aim to provide a better, more complete set of data.

So why's that good? Well, in isolation gym equipment and the Apple Watch used for indoors can be a little incomplete. The watch is good for heart rate, but distance, accuracy and elevation on a treadmill is impossible. Likewise, no-one actually calibrates their treadmill in the gym, so even if you do use a chest strap (no-one does) calorie burn is normally way off.

Using GymKit - how it works

Wareable was invited to a test of GymKit at the UK's first location in London – Virgin Active Mansion House – which has just upgraded its TechoGym equipment to support GymKit. You can see that pictured above.

With the GymKit support built into watchOS 4, everything is contained within the Workout app – so if your smartwatch is up to date you're good to go. However, you don't even need to touch your watch to get started. Once on the treadmill, we just tapped our Watch against the sensor. This automatically opens the Workout app, and a quick confirmation that we were ready to begin was enough. The treadmill then fired into life, and we started our workout as normal.

Heart rate is measured on the watch, but displayed on the TechnoGym treadmill's massive screen. They were never more than a second out of sync at any given time, and you could barely discern any difference between the two sets of data.

GymKit is also designed that you don't have to pair the two before your workout. If you start a session and forget to pair your device, you can then tap at any point, and the data will sync up. You'll get full credit for the session on your Apple Watch and in the Workout app.

It's much like using Apple Pay and works as seamlessly. Tap and the data is there. Stop the workout and it stops on your Apple Watch. It's really as simple as that.

As you'd expect from Apple, it's not massively data rich – and it's hardly breaking down the barriers of running experiences. However, from a run you're able to see calories, distance, time, average pace, elevation gain, average heart rate and recovery heart rate. And from a treadmill run, that's actually a staggering amount of data. You'd be hard pressed to find that level of detail anywhere else from an indoor workout.

Cyclists will also be pleased. In addition to that same data you'll get power wattage and RPM from the bike, which is data that even outdoor cyclists struggle to capture. And if you're into the stepper, you'll get floors climbed too, which would previously have been impossible to measure from just the Apple Watch.

With the arrival of watchOS 5 later this year, Apple has revealed more features that are on the way for GymKit. The headline features are a new yoga tracking mode that is based largely on heart rate, a hiking mode that takes into consideration elevation and new running metrics including cadence, pace alerts. So GymKit is going to get a little better better a tracking your workouts.

GymKit compatible tech

Apple has managed to wrangle up the biggest gym equipment manufacturers in the world to support GymKit.

Life Fitness, Matrix Fitness and TechnoGym are the major players involved. In addition to Life Fitness and Core Health and Fitness, who include well-known brands like Cybex, SCIFIT, StairMaster, Star Trac, Schwinn and Nautilus in their portfolios. Between these brands they ship 80% of the equipment used in gyms, so there's plenty of support. And Virgin Active gyms are starting the rollout in the UK, and Equinox/YMCA in the US.

But the GymKit rollout isn't going to mean your watch will connect to every piece of equipment in the gym. It's limited to treadmills, elliptical (crosstrainer) machines, bikes (although not spinning bikes yet) and steppers. Resistance machines and other equipment don't get the GymKit love.

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Life Fitness will be rolling out compatibility with its Elevation Series cardio line, which includes ellipticals, treadmills, stair machines, and cycles. Specifically, it'll come with the Discover SE3 HD consoles. Only the Life Fitness-branded machines will be GymKit compatible at the start. Other machines in the brand, like those from Cybex and SCIFIT, will arrive in the future.

Matrix Fitness will add Apple Watch compatibility to its 7xi and 7xe consoles, which are used for treadmills, ascent trainers, ellipticals, climb mills, and upright, recumbent and hybrid exercise bikes. TechnoGym, on the other hand, says it'll roll out compatibility to "favorite equipment", which'll include treadmills, ellipticals, indoor bikes and stair steppers.

When will it roll out to your gym?

The first GymKit-compatible equipment has already started rolling out. Virgin Active gyms in the UK have already started upgrading their TechoGym cardio machines. Core Health and Fitness says it'll add GymKit compatibly to its OpenHub series of cardio consoles for its Star Trac, StairMaster machines, as well as its Schwinn cycling equipment.

But like many of Apple's best ideas, this isn't new – it's just a simple and convenient addition. Life Fitness and TechnoGym, for example, have the apps that allow you to sync your iPhone or Android to their gym equipment. You'll get all your workout information, and you can even combine it with outdoor workouts if you'd like. Apple's just improved the set up – and the company confirmed that for most equipment, only a small upgrade of the NFC sensor and a software update is required.

And the fact that some old equipment can be upgraded should vastly speed up the rollout of GymKit tech, in addition to it coming as standard on new gear.

An Equinox representative, for instance, told Wareable, the gym is aware of the technology and plans to utilize it in the "near future." Other major gym chains in the US, like Planet Fitness and LA Fitness, have not yet responded as to when users can expect new equipment rollouts to begin. Gyms typically change up cardio equipment every couple of years, but it's unclear whether they would break their cycle for Apple and gym manufacturers itching to get Watch users in the habit of syncing their workouts.