Fitness trackers used to just be for step counting and sleep monitoring, but now they're becoming powerful tools for those who spend time in the gym. Like the swim trackers and cycling trackers we've already put through their paces, there are options for people who want more than just basic activity.
So what does it take to be a great gym tracker? In our eyes, something that's built to withstand the rigours of a tough workout is definitely a priority. Then there's making that progress in real time easy to digest, actually making you feel like you are working hard and let's not forget making sure the sensors are serving up reliable data.
Essential reading: A love-hate relationship with gym wearables
We've picked out five of the best trackers available that promise dedicated gym modes and the ability to do more than just measure distance on the treadmill. These are the wearables that want to help you get a sweat on and get the most from your session.
From spinning sessions and bodyweight training to lifting weights, we put these trackers to the test. We also measured the reliability of the heart rate monitors, to see if they really are capturing the intensity of your workout
Here's how they ranked, along with our final verdict on the ones you need to own and avoid.
Under Armour Band – 5th place
I was pretty underwhelmed when reviewing the Under Armour Band the first time around, and things don't get much better when zeroing in on gym time tracking. It's the ugliest of the trackers on this list and has one of the worst resolution screens, making it difficult to quickly see progress.
In terms of gym-centric features, there's not a lot going on here. Yes, there is a dedicated gym mode, but the data recorded is basic at best. The optical heart rate sensor isn't up to the task for high intensity training either and is the reason why Under Armour bundles its UA heart rate chest strap in the UA HealthBox, as a way to make up for its limitations.
Wearing it during a workout isn't a problem. It's light and comfortable and I didn't experience any sort of irritation. The one issue I did have is that it's all too easy to accidentally pause a workout.
The saving grace is the Under Armour Record app, where the data is shared and you can see how much more (or less) you worked out than the previous day along with a graph showing workout trends.
When we spoke to HTC recently it said that buying the Band separately means you lose the essence of what HealthBox and Under Armour's vision of fitness tech is all about. This experience confirmed it and is a let-down of tracker on its own.
Polar A360 – 4th place
Like the Under Armour Band, we had high hopes for the Polar A360, the company's first fitness tracker with an built-in optical heart rate monitor. The truth is that it doesn't really excel in any department, including taking it for a trip to the gym.
What it does have on its side is a bright, vibrant screen that's easy to view along with a comfortable strap. You really do need to make sure that the removable screen is securely snapped into place, though, or it will move about.
In training mode you can track a series of exercises including treadmill running, boxing and swimming in the pool. To add more, you need to go to the Polar Flow website before they can be synced to the A360.
We were most interested in how the Polar's heart rate sensor held up, because this is where the core data comes from. If you're not running, then you're only going to see duration, calories burned and heart rate zones. Against the Polar H7 during a exercise bike session and some circuit training, BPM readings are generally accurate but can quickly become erratic once you pick up the pace.
Unlike the Under Armour's tracker, you're not going to accidentally pause a workout here although data can be very slow to sync back to the Polar Flow smartphone app. It's quite a busy looking place to review workouts, but it gives you a nice breakdown showing a percentage of fat burn, HR average and max scores alongside a heart rate graph.
Polar also includes a fitness test option, but you'll need to pair a compatible heart rate monitor chest strap to get any use out of it.
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TomTom Spark – Bronze medal
The TomTom Spark is built for running and that's where its best features lie, but you do also get a decent cycling and swim tracker as well as activity tracking that seems a bit of an afterthought. The music player deserves a special mention too if you want to leave your phone behind, and it finally works without issues.
For the gym, you've got indoor cycling and treadmill running well catered for, although you'll need a compatible cadence sensor to get the most out of it. Against the Moov Now, treadmill running is accurate and you do have the ability to calibrate if you need to.
You also get freestyle and gym tracking modes, which like the rest of the devices in this test will let you see workout duration and bpm heart rate readings. What it lacks in insight, though, it makes up for in accuracy. Against the Polar H7 heart rate monitor chest strap for circuit training and interval exercise bike sessions it held up well and didn't register any erratic readings.
What let's the TomTom down is what happens with the data once its synced to your phone. It's just not given the same love as its other modes, showing you a pretty basic view of workout sessions.
Fitbit Blaze – Silver medal
The Fitbit Blaze is the most straightforward to use and is a good everyday tracker that offers a dedicated mode for lifting weights, elliptical training and treadmill runs using the built-in accelerometer. Like the Under Armour Band, TomTom Spark and Polar A360 though, you're only getting data here on duration and heart rate, but it's at least information that's easy to digest and make sense of.
Fitbit does include some extra gym-friendly features such as Smart Track to record exercises automatically, as long it lasts for longer than 15 minutes. You can adjust that to 10 minutes from the app though. There's also built in FitStar workouts with a limited amount of routines to choose from for now.
It's comfortable to wear, doesn't budge during a workout and of the five trackers is the nicest to wear all day. The Blaze actually holds up well in a series of bodyweight, dumbbell workouts and some interval training on an exercise bike. Against the Polar H7 heart rate monitor chest strap, accurate readings can take a couple of minutes to kick into gear at times, but after that, it's pretty much on the money. It can be a touch more erratic during FitStar workouts, as we found in our full review, so there are still some question marks over its reliability when you're not running or cycling in the gym.
Read this: Optical HR accuracy: The experts speak
Reviewing the Blaze's data is by far the easiest of the tested trackers. You can scroll down to the logged workout section and see a breakdown of duration, calories burned, average bpm and a percentage of fat burn. It's not a flood of data but it's certainly going to be enough for most.
Atlas Wristband – Gold medal
Out of all the trackers we've tested, the Atlas Wristband is the only one that's geared specifically for gym workouts. It can automatically recognise a catalogue of exercises with or without weights, counting reps so you don't have to in freestyle mode or in coaching mode. There's a heart rate monitor on board, and it's well equipped for most workouts as we found out in our full review. It's also waterproof, with Atlas promising to add swim tracking in the future.
It doesn't have 24/7 activity tracking in the same way that the A360, Blaze, Spark or Under Armour Band do, because it's designed only to be worn when you're in the gym. Aside from the ability to count sit-ups or bicep dumbbell curls, it can also track running and it held up well when we put it up against the Moov Now worn around the ankle and the TomTom Spark's treadmill tracking.
We can't really fault what it promises to do, which is to recognise exercises and reliably count them, sending a vibrating alert (coach mode only) when a set is done. The Atlas app is well designed too, giving you a nice breakdown on your session and showing the parts of the body you've been working on.
What does let it down is the look. Despite being light and comfortable to wear, it just looks ridiculous on the wrist. The jutting out screen makes it look like a Tetris brick and there's nothing discreet or elegant about it.
It's a shame because aside from that, it's the one tracker that really is going to make a difference when you're working out in the gym.
No one device here is the complete article for the gym but the Atlas Wristband is the best gym tracker we've tested. For dedicated training the Atlas comes out on top with its automatic rep counting, but it's let down by that odd design and a lack of insight into correcting form. The Blaze is the most versatile option and unlike the Atlas, is nice to wear 24/7.
The TomTom Spark is my personal running watch of choice and despite the limited data for gym workouts, the heart rate data is reliable. TomTom definitely needs to do a better job presenting that information in the companion app, though.
As we found in our swimming tracker test, the Polar A360 is underwhelming but it's the Under Armour Band that is the most disappointing of the bunch. The design is drab, the screen is hard to read and you need to wear the additional Under Armour heart rate strap to really get any great use out of it. That great software and ecosystem mean nothing if the hardware is not up to scratch.
Got any questions about our big gym test? Let us know in the comments section below.