Thanks for your swift reply.
I understood the metric, but wondered about the power variable. Under sport settings I can choose to tick of "Power", and the explanation given is that power is either recorded or calculated. My impression is that without a recorded power (or more correct as you state a device that estimate power), all metrics and calculation with relation to power gives no results. I have neither a device that record power, and hasn't tested anything else.
Therefor I wondered since the explanation says is either calculated if not recorded.