Comment by zdragnar
Muscles atrophy without consistent activity. VR can't replace that for someone with a broken hip / leg / spine. The whole cardiopulmonary system weakens with age, as does the immune system and healing takes longer, so an injury from a fall is much harder on the body than an equivalent injury to a younger person.
The comparison is between active VR participation (not simply watching TV in VR) and passive activities like crosswords during the recovery period of reduced mobility.