Nexus review

What's the best wearable for tracking CrossFit? The answer to that is that there aren't a lot of great options out there from the big wearable tech names right now.

While the likes of Apple, Fitbit and Garmin serve up devices that are able to measure a lot of activities from the wrist really well, CrossFit isn't one of them. The usual approach is to offer basic metrics like workout duration and heart rate. CrossFit though focuses on complex movements that uses measurements like weights, tempo, reps and recovery time.

Nexus is a wearable device that wants to cover those complex tracking bases putting the focus on measuring reps and sets from your session automatically. It then takes that data to offer insights to help you make improvements over time.

I've been putting in the CrossFit hours with the Nexus to find out if this is a dream companion for lovers of the intense fitness regime. I should mention that a number of the promised features were not live at the time of testing, but I'll update my thoughts when they've been rolled out. Here's my verdict on the Nexus.

Nexus: Design and how it works

If you’ve tried to do a CrossFit workout while wearing a smartwatch or a fitness tracker (especially some of the chunkier ones), you’ll know that a lot of the movements are quite difficult to carry out – especially when using kettlebells. Not only does it make you constantly worried that you’re going to break your expensive wearable, but it also means you often end up having to take it off because it’s starting to violently rub against your arm.

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The Push band, which forms the core part of the Nexus kit, is a fairly bulky device when compared to the sensor on a heart rate monitor chest strap. It's about two or three times the size of the sensor on a Myzone or Polar chest monitor. You can wear it using two methods: the first is a compression sleeve worn on one arm, and the second is a velcro strap which tightens around the forearm.

Both are actually very comfortable, and although it appears chunky, the band is actually very light. Once you have it on, it’s barely noticeable. When wearing the compression sleeve the band fits into a small elasticated pocket at the front and I didn't find an exercise where the band really got in the way.

On a purely aesthetic note, there’s a certain level of vanity in wearing the sleeve while working out. You oddly feel as if you look like someone who’s there to train hard. Style, when it comes to CrossFit, is something people can take very seriously and it’s definitely been made with that in mind. In the future, if CrossFit wearables do become increasingly popular I wouldn’t be surprised if it becomes a popular style accessory instead of just a functional tool.

So how exactly does Nexus work? The actual tracking device is an existing piece of tech from a company called Push; a sports performance company that build both hardware and software for strength and conditioning coaches. The Push band contains an accelerometer and a gyroscope to measure movement patterns.

The main measurement used is velocity (the speed something moves in a specific direction). The general concept is that coaches can use the tracking tool to see the level of effort being output by an athlete, based on the fact that velocity is often difficult to measure with the human eye.

Nexus: The CrossFit test

As you would hope from a device that essentially tracks one specific thing, the set-up and usage of it is relatively simple. Once the band links with the Nexus app you can set up workouts using the simple interface. This process means searching through the selection of exercises that exist in the apps database and building your own workout. Currently there are over 140 individual types of movement that can be tracked in the app and turned into a workout. From the fifteen or so workouts I built, there were very few movements I couldn’t find. According to Nexus, more exercises are constantly being added to the setup.

In my time with it, there were two formats of workout available: For Time and an AMRAP (as many reps as possible), which covers a large chunk of what most people will need. The greyed out selections in the app show what they’re planning to release: EMOM, TABATA, Lift, Rest, Pre/Post and Skill. If you want to make it easy and just do a workout from the archives of the CrossFit world (Like Murph or Annie), then these can be selected from a pre-populated set of CrossFit classics. Once you’ve chosen your workout from one of the methods you select it. The button at the top of the band itself will then kick off the timer to start the workout.

The live workout screen in the Nexus App supplies some data once the workout has started, but not a great deal. As well as listing the reps and exercises that you need to do, it also has a timer (depending on if you set one up) along with the round number that you’re currently on, cadence and power.

Initially, during the live workouts the data isn’t particularly useful. However, once you use it more and more for the same style of workouts, you do start to understand a bit more about what sort of cadence and power numbers you should be aiming for. For the most part you generally know how hard you're pushing it during an AMRAP without the live information, but for the more complicated movements, like a snatch, it is a good gauge to see how efficiently you're doing it. Increasing the power means that you’re performing the movement faster, which is a good indicator of improvements as you continue to train.

Nexus: The app

The really impressive insights from the Nexus come after the workout, as you start to delve through the details. Although the data it seems to be pulling through is relatively simple, you suddenly realise how useful it can actually be when visualised in the clear way it's presented inside the companion app.

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At the core of the reporting is the ability to monitor work. This is the force required to move an object by the muscles for a specific distance and gives a result in kilojoules. This work number is used as a measurement to look at the amount of training and the level of that training over time. It’s also used to work out power, the primary recording unit for the Nexus.

As it pulls through the rep count of the exercises in your workout, it also calculates the power of each of those reps and how quickly you did them per set. The result of that is a set by set breakdown of how you performed. The plus point of this is that you can break that down by each exercise over the time period and see where you might have had issues across the full set. So for instance in the screenshots above you can see the cadence dropping significantly for the third set of pistol squats. Over time that might show areas for focus in a training plan, suggesting the points where you’re most likely to fatigue.

An average power chart is also displayed showing the fluctuations throughout the whole workout. For your average person, this may be inconsistent as people stop for water or to catch their breath, but for athletes this could help aim for a consistent power output, similar to the system used on a Watt bike.

Finally, you get a simple yet extremely useful breakdown of work versus rest time, a stat which more often than not gives a surprisingly easy way to use data to push yourself to work harder on the next workout. For the first five workouts the amount I found I was resting was always significantly higher than perceived.

Ultimately, the varied nature of the workouts and the thousands of combinations of exercises will have a massive impact on the reports and what they mean, and there’s a level of effort needed to get the best out if it. As with most tracking tools, the information supplied is there to be interpreted. You may see what happens if you lower your rest, or you could just try to improve your power output. It entirely depends on the individual and how they like to train.

Nexus: Accuracy and battery life

I did have some issues with the tracking accuracy of my workouts on the Nexus. When I first started using it I created quite detailed AMRAPs using a number of exercises. Sometimes this was fine, but other times I’d find that the rep counts were slightly off or the final graphs looked odd. In the example below you can see that the tracker appeared to lump two sets into one, which skewed the rest of the results.

In order to look into this further I broke the workouts into smaller blocks and found that there were a number of factors, which can affect how the reps are counted. Sometimes these can be human errors, e.g. moving your arm at the wrong time (like scratching your nose or picking something off the ground) or just doing the exercises slightly wrong based on how the app thinks the movement should work. The app tries to rectify this by having a granular set of movements available in the app, so it can tell the difference (e.g. ‘arm still’ squat and ‘arm swing’ squat).

Occasionally the tracker would also just miss a rep for some reason, then be out of sync for the rest of the workout. As one of the first trackers of its kind, it’s inevitable that these issues would crop up and there is a feedback email button for the reports so they can look into the incorrect data and work on rectifying for future releases.

On the battery front, the Nexus wearable should give you around 30 hours of tracking, which is a fair amount of CrossFit hours tracked. Based on my time with it, that seems to be pretty much on the money. Thankfully, it doesn't take too long to charge either so you won't be hanging around before heading to the gym to track your next session.