I do both. its always good to work the muscle in different ways
also you have red and white fibers. white get worked when you go heavy and low rep. red is the opposite. its good to do both if you are a gym rat or bodybuilder, powerlifters will work on their whites primarily .. a PLer who has been doing that for years would struggle to do 1 plate for many reps cause they are all white and barely any red.
also genetics play a roll too. some guys just are born with a bias to one or the other ... some guys are 50/50.. some are 90/10. just depends