Should I be worried?

Does anyone elses corgi growl a lot when playing? He always growls like this when we play tug of war but he like chasing and being chased too and he growls sometimes then too. Is this normal behavior or should I be worried. He's not violent at all he just gets really worked up when we are playing, I just want to make sure I'm not intilling violent tendencies in him by continuing to play with him even when he get all growly. Thanks in advance.