It doesn't need any equipment other than an iPhone or iPad running iOS 12 (an Android version will arrive in the next few months), though you might still opt to use a fitness tracker. Once you get into position around seven feet away from your device, the app's AI uses a 16-point system to compare the way you move to optimal movement, looking at factors including the positions and angles of your limbs and joints. The app will tweak the difficulty level and exercises based on your feedback.

Kaia Personal Trainer is available through the App Store. In the US, there's a seven-day trial, then the app costs $29.99 for three months. For the time being, it's free outside of the US.