Hi all, I'm revisiting my musings on plausibly strengthening the human skeleton to better withstand the stresses of combat, melee in particular. If y'all don't care about background, skip to "The Question" two paragraphs below.
In my setting, space marines (in the sense of soldiers who board space-/star-ships, not the Warhammer kind) have always preferred melee combat during boarding actions. In the early days of space-flight, people were still using kinetic weapons to defend themselves, and this practice remains widespread planetside. Aboard starships, however, it was quickly discovered that the bulkheads separating the warring marines and the Void weren't quite up to the challenge of shards of metal flying at obscene speeds.
Rather than wait for starship manufacturers to catch up to this, many pirate factions switched to melee weapons such as swords, spears and shields. These shields are the key: being made of a MacGuffinite alloy (haven't gotten around to naming it yet), it is able to stop most kinetic small-arms fire with very minimal damage to the user. This lead to guard crews and eventually the Space Marine Corps to adopt similar weapons. Nowadays, an advanced and ancient race of humans from another planet has decided for various reasons to adapt the biology of their marines to this new melee combat, so as to not need the obscenely intricate and finnicky powered armor that other factions have taken to using.
Now, I'm going to address changes to the overall structure (e.g. bone shape, placement, etc.) in another question. For this one, I'm more concerned with the materials, composition, and structure of the bones and ligaments themselves. First off, I've seen somewhere that someone suggested coating the bones in a cartilage membrane. Now, what if we took that to the next level, and interwove that with carbon fiber? Also, could we actually embed a sort of carbon-fiber "rebar" within the bone itself, and potentially even include a core made of more rigid CF (sorta like that stuff new fancy bikes are made of)? This leads to another concern: is it plausible that there are certain enzymes within the cells of the skeletal system that are able to synthesize and lay down this carbon fiber matrix, a sort of carbon-fibrase? As for ligaments, would making them out of pure carbon fiber be better than a mix of carbon fiber and normal cartilage, and would either of those be better than just the cartilage as it was before messing with it?
Alternatively, might another material be preferred over carbon fiber in this context, either for mechanical or chemical reasons? I was thinking carbon fiber because, well, we're carbon based life forms after all, and I reckon that the materials to make it wouldn't exactly be hard to come across in the diet. Plus, my understanding is its strength-to-weight ratio is outstanding compared to bone. Note also, I'm wanting this metahuman to be much stronger than a normal human too, so that's another reason to strengthen his skeleton to better cope with the increased stresses exerted by his musculature.
Thanks in advance for your answers!