Just cycling workouts on the 530 (morning HRV on Apple Watch). Another ftp estimate at the end of ride - 265 - which was surprising given the grab bag of short efforts.
Others may not see the same results, it’s using HRV/HR/power, but this 530 and Garmin dual HRM is working well with my training. Nothing earth shattering, just reinforced I need to get more sleep after staying up too late a few times this week. Didn’t need a computer to tell me that, not wanting to push out upper endurance after 2 hours was a good enough signal.