There are a couple really important things to understand here:
1. When people say “full plate armor” what exactly are they talking about? Plate armors have been used for centuries and even the “Middle ages” of Europe were several centuries long- in that time many styles and variants and advancements came. Many countries and even makers had their own styles- and in the same period you would usually see multiple types of “plate armor.” The armor most professional knights wore to battle would not be the same as heavy armors used for predictable sports with rules like the Joust.
2. The second thing you must understand and question whenever people debate what can be done in “plus armor” is that the armor itself is just metal. Wearing a bulletproof vest, you can die even if the bullet doesn’t penetrate the vest- the force is still transferred to the wearer to degrees. Mauls, Maces, Hammers, Clubs, Heavy axed etc are excellent weapons to injure or kill an armored combatant- even if you don’t pierce the armor.
For this reason as well as the weight and potential for the armor itself to act as a “weapon” against the wearer of an edge of plate or such “digs in”- usually lots of padding was worn underneath. This padding could be a major restrictive to mobility. Wrap you arm in a large and thick blanket and you might get some idea of it doesn’t make sense to you. So if you’re ONLY wearing the plate and not any of the padding- your mobility will increase but that’s not necessarily the configuration they would have worn in the period.
Also note that often times modern reproductions are made of modern alloys that may not have been known or may have been extremely prohibitive to the point anything similar would be VERY rare if you could find it at all. Modern reproduction armors also often substitute other modern materials or fastening systems as improvements to the designs of the time. So we do have to question when looking at any example of “plate armor” how authentic it is to the period as well as if the wearer is using other period correct accessories etc.
3. Mobility is... relative. So- we already talked about how the design and purpose of the armor would affect mobility or not. Generally after a point of spending money for the “best” the time had to offer- you’re going to be sacrificing protection for mobility, or protection against one type of threat for a wider range of lesser protections. This is even true today of armor- the “Armor” you need for a space walk to protect against radiation and temperature and vacuum is much different than the “armor” you’d drop into a modern fire fight in, and that’s much different than “armor” to protect against NBC threats.
Modern soldiers have had armor protection since at least WW2. We went from large and heavy metal plates for Flack protection and some small arms, to lighter but still heavy plates and carriers like you’d see in early gulf engagements. Modern soldiers armor is much lighter and generally more effective- but it’s still heavy and far from perfect.
A soldier can easily be carrying 60lbs or more of gear including armor. This effects mobility. Weapons slings can effect mobility, backpacks etc. and that’s with 500+ years of ergonomics and materials science. But one thing is very true-
You can’t likely run very long in most “ full plate armor” and you’ll be pretty gassed after. Even with all the ergonomics and much better breathability and load distribution and support- modern soldiers get tired out. With a set of “full plate” it’s entirely possible a user could run, jump, and if so designed- have a pretty full range of motion and relatively decent vision of their surroundings.
But it all depends. If you are Calvary or such- mainly fighting on horse back- heavier armor still may tire your horse or slow it down- but it’s much easier to manage and if you aren’t traveling far- you may want the extra protection. A purpose built armor such as for the joust would often have one or more large pauldrons, and you wouldn’t need to run or jump or move your arms much if at all above the shoulder or move freely at the elbow. To the contrary- for your protection and to prevent injury you’d likely want armor which prevented links from moving too much.
So often times the idea of “full plate” making you a lumbering blind tank, comes from jousting armor of certain periods or other such “heavy armors” or from “wall hanger” type reproduction armors used in display and made of poor alloys and poor design to look attractive and not be worn- or especially not be worn in combat.
But with that said- we can’t ever say “plate armor does this” or “plate armor does that” because there are a lot of variables. There was plate armor that was pretty light, easy to wear relatively, and well designed. There was plate armor that wasn’t. There was plate armor designed specifically to restrict mobility. A well to do professional armored soldier would likely either have multiple armors or for the most part stick to what their armor is made for- or in a pinch use it for something it could probably still be ok at.
The same is true to day. Explosive ordinance technicians wear very heavy, very restrictive armor for their protection. It can be hard to wear for long periods and seriously restrict mobility. But if we were in the future talking about “soldier armor” we couldn’t base our ideas on the body armor police use and the body armor a general infantryman uses and so forth, just off one type of armor. We certainly shouldn’t base it on a soldier cosplay.
Just like modern military and police have different types of armor and different types of units and specialists and tools and weapons- it wasn’t so different in that way in the “Middle Ages.” They already had the concept of the specialist down, perhaps not as refined, but they knew what specialization was and how it could give tactical advantage or disadvantage. War is a constantly evolving doctrine. Some times old strategies or weapons and tactics or doctrine come back, sometimes they have their moment and then are gone to history of war.
“Full plate armor” was an effective tool. It wouldn’t have been used for so long if it wasn’t. But it was a tool that fit a certain doctrine and a certain time. Asides from cost and upkeep and the specialized skills of making and maintaining and even using it- we can view it much as the protection systems we have used since into the modern day. A soldiers helmet won’t stop every bullet, and if our body armor was so effective we’d have less dead and wounded soldiers. But it’s protection against weapons and tactics today is greater in most general situations than the draw backs.
“Full plate armor” met a cross roads where the protection offered started to be less than the draw backs, and doctrines changed. People debate endlessly if guns are effective or not against “full plate.” Asides the previously listed differences between sets of armor that would effect that- remember that bullets back then were much different as were guns. While early riffles didn’t have the accuracy or ease of effective range and consistency of newer weapons- they are quite effective or rlse we would t have kept perfecting the technology. They were also generally bigger. A standard” bucket would be about the size of a modern .50 cal round but a ball. It’s big danger would t likely be penetrating the armor- but the fact that the blunt force of impact would be transferred to the squishy human inside.
This is a problem we even have today- getting shot even with a Kevlar vest will generally hurt and could kill you from the force of impact. If a modern small caliber hand gun bullet can break your ribs- imagine what a .50 cal ball might do.
Plate just isn’t effective in modern doctrine. You may be able to run and jump- but try crawling through a swamp or jumping from a plane or squeezing through narrow spaces of an urban battle ground in it. Try standing in the Afghan sun for a patrol in a giant oven. If it were so effective- who wouldn’t some military somewhere combine “full plate” with Kevlar and create a modern super armor?
Tl:dr and conclusion- ever see the infomercial where they cut through a can with a knife to show you that it will? How long, how many cans you think you can cut with that knife? They only need it to cut one, once. “Full plate” is a wide spectrum of armors from a wide spectrum of countries and time periods and purposes. It worked in its heyday. It generally isn’t like wearing a dumpster- but the reality of 50-100+lbs of metal strapped to you is going to take its toll. You may be fine for a minute of running or an hour of wearing. Wear it everyday for hours. “The weight is distributed...” really? Because backpacks and even just have boobs can give people trouble and even long term disability. The fact that you CAN run with weights strapped to your body doesn’t mean you should, or that it’s sustainable.
Lol. I’ve been working on something. But the missus (and her very prominent chest-friends) haven’t liked most of my prototypes using modern tech to solve the problem. The fundamental problem is distributing the load somewhere besides the shoulders. My leading solutions were:
Drones with “slings” more or less, hovering around “sky lifting” the girls. She found this ridiculous- although it is technically sound so long as one remembers to charge their bra.
The other was a system adapted from a DAPRA design to allow soldiers to carry more gear. It uses a system of pulleys and cables which attach to the shoes and allows the weight of the breasts to be carried spread out- and mostly in the legs. I didn’t even get to prototype demo that one as the idea of a full body rig was a hard no- and she’s my focus group so that killed that. When I have time and am not on another project I turn my mind to it.
It’s a very serious problem afflicting hundreds of millions, and along with “pockets in dresses/clothes” is a plight I am highly passionate about. The fact that our breast-centric society has been content to gawk and objectify breast’s for centuries while barely developing means to aid women in their peaceable enjoyment of their lives is sad. Breasts shouldn’t be a burden, wether that is being objectified or having to take the stairs, or just having to stand long periods. We can make a suit to allow humans to walk amongst the cosmos, but we can’t strap the girls down for a run without it ending up in medieval torture or a black eye? My inner scientist is offended by this.
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(TITLE FROM REDDIT r/gifs)
1. When people say “full plate armor” what exactly are they talking about? Plate armors have been used for centuries and even the “Middle ages” of Europe were several centuries long- in that time many styles and variants and advancements came. Many countries and even makers had their own styles- and in the same period you would usually see multiple types of “plate armor.” The armor most professional knights wore to battle would not be the same as heavy armors used for predictable sports with rules like the Joust.
Drones with “slings” more or less, hovering around “sky lifting” the girls. She found this ridiculous- although it is technically sound so long as one remembers to charge their bra.
The other was a system adapted from a DAPRA design to allow soldiers to carry more gear. It uses a system of pulleys and cables which attach to the shoes and allows the weight of the breasts to be carried spread out- and mostly in the legs. I didn’t even get to prototype demo that one as the idea of a full body rig was a hard no- and she’s my focus group so that killed that. When I have time and am not on another project I turn my mind to it.