@nether
If you weren't going outdoors at all, then you or someone in your household must have been CEV. And even then it was only the first 12 weeks when CEV were told not to go out even for daily exercise.
The local rules orr the venue of the karate club sound appalling, but that's what they were - idiosyncratic local rules - not part of what lockdown required (and of course nothing to stop you walking round outside close to the venue if you wanted to get your paces in during the DC's class)
I did go out, but my body can only take 2 hours of running in a day and not every day. We did have walks and ignored the one a day guidelines and Gove's imaginary time limits, but that still leaves another 8, 9, 10 hours a day of moping around the house avoiding disrupting office life upstairs.
Compare that to walking the DCs to school 2,3,4 times a day depending on activities. The DCs running around at break and lunch time with friends, walking to activities. Going places and walking around shops.
I go running anyway, but the incidental movement is important on top and is hard to substitute.
As to the Karate club, council venues and community centres are still full of box ticking, ineffective measures. Our youth groups still have to wash/ sanitise on entering, contact with parents still limited, still having to risk assess activities to Guiding/ Scouting and in turn Youth Association guidelines and venue guidelines. Still ticking off on the form that we've sprayed all touch points on entering and leaving to satisfy the venue committee.
There is still a huge amount of measures out there that are very culturally difficult to abandon because there is still an obligation to produce "Covid Secure" risk assessments.