From what we know of charges, they would often ride very close together (knee-to-knee even, though this differs greatly per region or cavalry type, I'm primarily talking about knights) and point their lances forwards for optimal shock effect. When connecting with the enemy, it would be most beneficial if the rider would not stand still and fight in the melee, but ride out as soon as possible in order to charge again. A relatively slow moving man on a large horse is an easy target.

Later (1500-1600) the knight would be very heavily armoured, and able to even resist against longbows and other weapons beside muskets.