No cadence without chest strap?

I know that you cannot get the "advance gen 2" running dynamics without the HRM Run strap but why cant we get a simple thing like cadence? I just did a run and the cadence is 0. Any ideas?

0 gasteropod over 8 years ago

I get cadence with the 5X without a chest strap or foot pod.

https://connect.garmin.com/modern/activity/1634571311

0 RDM01 over 8 years ago

I'm getting cadence data and I'm using a generic Ant+ HR belt. The cadence is coming from the F5 itself.