yes. but even a superman comic or movie is done in just a way to inspire adventure. So the lamp post never cleves through the villian, but does knock him clear to next week in a full body cast...
True, but those are just the unrealistic aspects of supermans retartedly high strength. Catching a person falling from a building while flying at full speed should snap them in half but never does.
In reality if you try to parry someone who has a baseball bat and he is doing an overhead vertical swing and you try to parry, you need to both have the strength to deflect part of the attack and have your weapon in a good enough angle that his attack slides off it instead of pounding into it, plus you'll need to have some amount of maneuverability incase he compensates and applies more pressure or force to his attack. Basically it means if you don't have the strength or training you can't properly parry someone who is stronger than you or better in combat. If you do try to parry then your opponent will overpower you and both you and your weapon will suffer.
If you want a fairly decent example of how it works since its really hard to explain it by typing and alot easier to explain it with some sort of visual reference, check out the anime Berserk and watch the episodes where Gatsu fights Griffith the 1st time when Griffith says "if you beat me in combat you can go free" and again near the end where Griffith makes the same proposition. Griffith in the beginning is both stronger at the time and more skilled, even when Gatsu is 100% Griffith is still at roughly the same level of strength but is more skilled than him. In the fight near the end of the series Gatsu has bulked up significantly to almost superhuman levels for both his strength and his fighting skill while Griffith hasn't really improved all that much.
1st fight, Griffith easily parries his attacks and repeatedly stabs Gatsu
last fight, Gatsu wins in 1 hit because Griffith is unable to overcome the sheer amount of power that Gatsu is hitting him with.
It's not a question about being able to parry, of course you can, it's being able to hold onto your weapon, and if you are, how tightly are you holding onto it? Too tight to be knocked out but not as tight as your can would prolly result in a broken wrist, as tight as you can(i.e. locking your wrists and bracing yourself) would prolly result in being pushed back a good number of feet.
Grip strength only really applies to your ability to be disarmed both when you attack or someone activly tries to disarm you...bad grip will result in you dropping your weapon or possibly injuring yourself when you attack.
If someone with far greater strength than you hits your weapon and you lock your wrists and brace yourself, the person attacking is going to power right through your defense and a number of things will happen to you.
1) you risk injuring yourself if your unable to withstand and deflect the attack.
2) your weapon will either take the full force of the attack and then be knocked from your hands or it'll take as much punishment as it can before it breaks.
3) the attack simply crushes your defense and hits you with so much force that you can't withstand it and he hits you and your weapon resulting in severe pain and anguish.
The whole knockback thing is for effect...in real life you don't go flying 10 ft if someone like superman hits you with a lamp post...in real life you go splat and get wrapped around the post in a gooey mess while bits of you splatter. When someone hits you they don't stop right when they connect, they keep powering on through, if they were stop the second they hit you then ya you might get some air time depending on how hard they hit.