Posture system added to the game. Your posture bar is shown below your health bar. Enemy name, health and posture is shown in the top middle part of your screen (below balance of power bar). You lose some posture when you attack, you lose more posture when you defend from enemy attack, perfectly timing of your block / parry significantly reduces posture damage which you receive and causes lot of posture damage to the attacker, blocking into incorrect side with the shield or holding parry for a long time before actual attack will result in more posture damage than perfectly timed block or parry. Posture regenerates over time. When soldiers posture fully depletes he will recieve some adverse effect (read below) and will regen half of his posture back (so you can turn the tide of battle evne if you are loosing at first).
If you attack enemy with shield that dont have enough posture to block he will be either knocked back (if he times his block in correct position properly) or knocked down (if the enemy does not block in correct position). However if you perfect parry / perfect block attacker that has low posture and is carrying a shield, this attacker will be knocked down.
If you attack enemy without shield that dont have enough posture to parry he will be knocked back and will receive crush through. If you perfect parry someone that has low posture, you will knock him down and cause crush through.
Heavier weapons (such as maces) are better at dealing posture damage but receive more posture damage when they parry in comparison to more nimble weapons (such as swords). 2 handed weapons are generally better for parrying thna one handed (they reflect more posture damage when they perfect parry). 2 handed swords are best for dueling.
You character weapon skills and athletics (or riding when on mount) affects you posture damage and posture regen.
You can disable posture system or its GUI in the mod options.

Two handed polearms, two handed axes and two handed maces will stagger enemy when they are parried by melee weapons or blocked by shields from incorrect angle, this should help with their shock capabilities.

Thank you but I read the explaination already at Nexus.
Sorry, perhaps I am blind but I can't find what I need in the text, I also expressed myself a bit unclear.

I don't use a shield and I had 90% of my posture left, plus I parried all blows perfect (not only blocking), but the Bandit Chief with his 1h axe was still able to crush through with every attack, this also decrease my posture a little bit(as it should be).
Very low damage, so no big deal but still wonder why that happens so many times.

Maybe just a bug?
Because when I understand the description correctly it should only happen when you don't have enough posture left, but then when you do a perfect parry you can avoid it and regen your posture.

Crash through or only stagger (ouch animation with no damage)? Because axes will cause stagger when they hit your shield and you dont do perfectly timed block with it but there is no damage associated with it. It is supposed to represent that you can use axe to drag enemy shield to break through his defense while someone else can attack him.

THIS
Thank you very much for your explanation, yeah it is just about axes and I was wrong, the there is no "low damage" there is no damage, it's just this stagger mechanic.

Amazing Mod btw

Another question - why are my posture regenerate very slowly compare to enemy.
Even recruit regenerate posture faster than me. Is there anyway to regain posture other than let it depelete?