So I was wondering, since nowadays soldiers tend to be fit, perhaps not have 6 packs, but usually visible abs since they do a lot of workouts and exercises to stay in shape, for example, the Battle of Grunwald let's say, were the knights in that battle(Teutonic Order vs the Polish) fit, or were they overweight, or did it matter? Did they have any stamina and do any type of training before fighting? How did that "basic training" look like?
I have answered questions about a knight's physique, about the training culture of the late medieval and early modern period; to quickly recap some of the key points: knights are depicted as having very narrow waists in period art, but are otherwise seldom depicted as having a great deal of muscle; and "basic training" was completely non-existent, training culture was more about learning on-the-job, under the tutelage of private instructors, or just by picking things up and doing them when time and circumstance allowed.
U/Knight117 answers a similar question here: https://www.reddit.com/r/AskHistorians/comments/6lhry3/how_did_medieval_knights_stay_fit_for_combat/?utm_source=share&utm_medium=ios_app&utm_name=iossmf Edit: added author username