The roman developed a really good fighting technique to beat their enemies:
At their time, the roman army was the best army in the world.
The roman soldiers had a really hard training, They were taught to do lots of things but the first thing that they were taught was to march because it had a big importance in their civilization.
The roman soldiers also had a really hard physical training.Lots of running, carrying heavy packs, swimming the summer...
They had a training to use their weapon such as fighting with heavy wooden swords.
Training is the major reason of why the roman army was so good.