And now he began to test himself by jumping onto a courser in full armor. At other times he would run or hike for a long way on foot, to train himself not to get out of breath and to endure long efforts. At other times he would strike with an axe or hammer for a long time to be able to hold out well in armor, and so his arms and hands would endure striking for a long time, and train himself to nimbly lift his arms. By these means he trained himself so well that at that time you couldn't find another gentleman in equal physical condition. He would do a somersault armed in all his armor except his bascinet, and dance armed in a mail shirt...
When he was at his lodgings he would never ceased to test himself with the other squires at throwing the lance or other tests of war.Froissart, Jean, Jean Alexandre C. Buchon, and Jean Froissart. Vol. 3 1812. Les chroniques de Sire Jean Froissart... / [Et du] Livre des faits du bon Messire Jean le Maingre, dit Bouciquaut. Paris: Soc. du Panthéon litt. Tr. Will McLean 2014
I should point out that Boucicaut's training was exemplary rather than typical.
I was reminded of Boucicaut when I read this.