Gripping the blade was indeed common practice. It allowed you to strike with the pommel and hand guards, utilising them as a blunt weapon. This was better used for armoured enemies as blunted weapons were more effective than attempting to cut through their steel armour. You would also use the lower end of the cutting edge to strike down on an enemy’s shoulder, using the added momentum from the weight being at the opposite end of the sword you were holding from the blade, to cleave through their flesh. This was called a reverse grip I believe?