I won't go that far, because each is very demanding in its own way, but yes, table tennis played at a reasonably high level with a reasonably athletic style is very, very demanding. I play a very active modern defence style of table tennis, kind of like Chen Weixing, covering lots of ground and throwing my body in all directions. After a hard couple hours of practice counter topspins and chopping from far behind the table, my legs and back are aching. Table tennis counter looping uses lots of body turning vs. just arm, and this can be very demanding on many muscle groups.