Quote Originally Posted by Tevo77777 View Post
Granted, plate armor is different, but that's plate armor. I don't think the training to carry a mail shirt is that much different than training to hike while carrying approximately the same weight.
In real life, a mail shirt wouldn't affect how you move significantly more than a backpack of the same weight.

In real life, a mail shirt would also be near useless as armor.

The only thing mail does is stop cutting, or slashing if you want a D&D term, but due to still being just one layer of supple clothes it only diminishes the power of blows a little, meaning the slashing blows get turned into blunt ones, and blunt and piercing impacts are not really affected.

Furthermore, the shirt only protect the torso efficiently, which is not as good as one may think since all your other important fleshy parts like the neck are basically a death sentence if hurt in a combat situation, and if you're likely to survive your less-important fleshy parts like the limbs getting struck initially you'll be enormously hindered.

Historically, mail armor isn't a shirt most of the time, it's a mail long dress with long flowing sleeves (to protect legs and arms), worm above a padded gambeson (to absorb impact), with various pieces of metal or leather to protect the head, neck, hands and feat, plus a thick midsection belt to avoid having allof this weight resting solely on your back. It is actually harder to move in that outfit than in battlefield-ready plate armor, as the weight moves around much more freely.

D&D characters don't have to worry about most of those concerns, but still it means that the fiction it represents consider that significant mail armor = issues for the non-trained.