Boucicaut.

This is coolbert:

From the outstanding Internet website isegoria.org December 23rd, 2022. 

"Boucicaut’s Workout du Jour"

 "Jean le Maingre, called Boucicaut, (1366-1421) was a French knight known for his rigorous physical training"

[....]

"I was reminded of this when Ben Espen recently shared this video, demonstrating that plate armor was not especially cumbersome"

See the YouTube video a demonstration of a knight of the period of the period wearing plate armor his training regimen of physical fitness. Ability to mount a horse without assistance a must.

"Plate armor is a historical type of personal body armor made from bronze, iron, or steel plates, culminating in the iconic suit of armor entirely encasing the wearer. Full plate steel armor developed in Europe during the Late Middle Ages, especially in the context of the Hundred Years' War, from the coat of plates worn over mail suits during the 14th century."

I readily admit I was wrong. Knights during the Middle Ages were able to fight afoot while wearing plate armor and not confined strictly to mounted combat. Combatants during the naval battle Sluys for instance boarding an enemy vessel would have been effective in a way I had thought not possible.

coolbert.