We also spend a lot more time stationary, doing exercises that stretch us or strengthen our cores:
"Right, on your hands and toes, bring your left knee up to your left elbow, then swap. Government guidance says you gotta do it for one minute!" (It does not.)
At least kata is still possible, always my favourite bit anyway:
"Once more to your own timing, then I'll pick on you each in turn. Normally I'd have a quiet word but that's not possible right now."