From Vegetius, Epitome of Military Science, 23
Recruits and novice soldiers are trained morning and afternoon in types of arms; but veterans and trained soldiers also exercised with their arms once a day without fail. For length of service or number of years does not transmit the art of war, but continual exercise. No matter how many years he has served, an unexercised solder is a raw recruit.
Special drill (armatura), [mock battles. wd] which is displayed on festival days in the Circus [Maximus] is learned not just by the soldiers under the drillmaster, but by all soldiers alike in daily practice. For speed is acquired by bodily exercise itself, and also the skill to strike the enemy while covering oneself, especially in close-quarter sword fighting. What is more, they learn how to keep ranks and follow their ensign through such complicated evolutions in the mock-battle itself. No deviation arises among trained men, however great the confusion of numbers.
It is also very useful for them to exercise with the [sword and striking post] because they learn to go for the flank, feet, or head with the point and with the edge. Let them grow used to executing jumps and blows at the same time, rushing at the shield with a leap and crouching down again, now eagerly darting forward with a bound, now giving ground, jumping back. Let them also practice hitting the same posts from a distance with javelins, to increase their skill at aiming and the strength of the right arm.
Archers and slingers put up bundles of brushwood or straw (scopae), for a target, removing themselves 600 feet from the target, to practice hitting it frequently with arrows, or stones aimed from a sling staff (fustibalis). This enabled them to do without nerves in battle what they had always done in exercises on the training field.
They should also be accustomed to rotating the sling once only about the head, when the stone is discharged from it. All soldiers also practice throwing stones of one pound weight (about 11 ½ ounces) by hand alone. This is considered a readier method because it does not require a sling.
They are also made to thrown javelins and lead-weighted darts in continual and perpetual exercises; so much so, that in winter-time they build riding-schools for the cavalry and a kind of drill hall for the infantry, roofed with tiles or shingles, or, failing these, thatched with reeds, sedge, or straw. In them the army was trained in arms under cover, when the weather was disturbed by wind or rain. But for the rest of the time, even in winter, so soon as snow and rain ceased, they are made to train on the exercise-field, so that no interruption to routine might weaken soldiers’ minds and bodies.
It is advisable that they should very frequently be felling trees, carrying burdens, jumping ditches, swimming in the sea or rivers, marching at full step, or even running with their [weapons], with their packs on, that the habit of daily labor may not then seem arduous in war. Whether they be legion or [auxiliary troops], let them be training constantly. As a well-drilled soldier looks forward to battle, so an untrained one fears it.
Finally, note that technical skill is more useful in battle than strength. If training in arms ceases, there is no difference between a soldier and a civilian.