I walk a lot. No running -- aggravates an old C2 neck injury. I might consider running again after this current round of physical therapy for the neck, back and shoulder injuries.
I stand fairly often to pedal, especially on climbs. I'd be surprised if that doesn't qualify as weight bearing. It's sure harder than sitting and spinning uphill. Feels about as hard as stair climbing exercises.
But if only impact type running counts as weight bearing to satisfy the current theories about bone health, I'm out.