I used to throw the javelin in High School and as an athletic sport it is completely different, a run up and a throw for distance. In ancient times it was used to throw into massed ranks of empty troops, not at particular individuals. I imagine skilled throwers could have done it with some accuracy.

Using a javelin for hunting is very different and requires a flatter throw with more accuracy. The elbow needs to be more bent or cocked than a long distance throw where the arm is fully extended at the point of beginning the throw.