Unless it was a TR typo, the study says "sitting for more than six hours during their leisure time"
Leisure time. Not work.
So, elevators, fire drills, activities at the work place, tools monitoring computer behavior, the authors choice of occupation are not related to this study at all.
Seems the author of this article didn't really read what the study says before writing this so I guess it's not surprising that no one else commenting did either.