The Role of Fitness in Historical Fencing describes the truly old-school fitness regimen recommended by Jean Le Meingre (Boucicaut), the marshal of France during the reign of Charles VI:
Now cased in armour, he would practise leaping on to the back of a horse; anon, to accustom himself to become long-winded and enduring, he would walk and run long distances on foot, or he would practise striking numerous and forcible blows with a battle-axe or mallet. In order to accustom himself to the weight of his armour, he would turn somersaults whilst clad in a complete suit of mail, with the exception of his helmet, or would dance vigorously in a shirt of steel; he would place one hand on the saddle-bow of a tall charger, and the other on his neck, and vault over him…He would climb up between two perpendicular walls that stood four or five feet asunder by the mere pressure of his arms and legs, and would thus reach the top, even if it were as high as a tower, without resting either in the ascent or descent…
When he was at home, he would practise with the other young esquires at lance-throwing and other warlike exercises, and this continually.