When VirFit was at the beginning, they sold a cadence sensor of their own. How much can an accelerometer cost? You can track full body movements with 3-4 accelerometer (2 for foot, 1 for hips), connected through bluetooth to Quest. This is the only way to introduce other types of movements, like martial arts or dancing. How can you introduce a dancing workout if you don't know how I move my hips and my legs? You could use a smartphone (with accelerometer and bluetooth) too, to map the movements of your hips.