With muscle mass being considered, I'd expect a six-footer who can fight with a heavy sword to be a 200-pounder. At 21, I was 5'10", 210, into martial arts, and able to do things that most would consider physically impossible... including me at 42. (And the same weight, dammit.)Other then age and weight, drastic variables 120-160 for a 6'3" person, extremely thin(Bean pole) to just thin. BMI chart shows 6'3 158-176 as small framed, 181-207 as large framed-good weight.
Age is not as big a deal, 19 would have less worldly exp then a 25 yr old, but the whole range in the era would be a trained adult warrior.
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