I'm curious since fighting with a spear one-handed seems to be rather awkward, especially if it has a heavy head (as I understand it, heavy counter-weights like the ancient Greeks used were not very common). Conversely, a heavy throwing spear would theoretically have far more penetration potential than either an arrow or a sword thrust, and if used as a shock weapon during a charge it wouldn't particularly need much range or accuracy.
There would often be a differentiation between a javelin and a spear at this point with a javelin being shorter and carried in groups of people armed similarly. The spear would have been used one handed, whilst the head is heavy its length means that it is balanced well. Also the fact that people would regularly train with them means that they can be used effectively, especially in formation. Spear over sword any day for me!