thatzac

on zombies:
ok, first off, zombiism is caused by a virus that would enter the bloodstream through a cut or something similar on a victim. when the fluids of a zombie enter through this opening, the victim is then infected, and will, within a day's time die and then revive as a zombie.
what the virus does is interesting. it changes how the cells in the brain interact and function, and also makes the brain oxygen independent. meaning the zombie does not have to breathe to survive. the central nervous system of the zombie remains operative, as well as some of the more "automatic" functions. the moan of a zombie is actually air being uselessly pulled into and then expelled again from the lungs. it just so happens that the vocal chords, which are now limp and not of concern to the zombie, since they do not communicate, allow for a sound to be made instead of just a strange wistful zombie-sigh.
another thing that changes is that the zombie becomes dumb. like really dumb. its primary goal is to eat flesh, but that is its only concern. if a mob of zombies saw you and there was, say, a ravine. separating you, the zombies would just continue to walk toward you and fall into the ravine. which is helpful.
but this single-mindedness also makes them dangerous due to the fact that the virus also turns off pain receptors.
while a human combatant could be defeated just through the threat of pain, a zombie will keep coming until it is killed because it has no worries about pain and will just continue on its flesh-eating agenda.
due to this fact a zombie will only truly die if its brain is destroyed. or, it has been around long enough for nature to take its course and the zombie rots. which could take quite some time.
interesting fact about the zombies' appetite for flesh: since their bodies are dead, they require no actual nutrition. this means that their hunger for flesh is due to the virus and not due to the fact that eating is necessary. the flesh that is consumd is in no way processed by the body, it is simply forced down. as a zombie continues to eat flesh, the meat is either finally forced out of the anus, or the zombie's internal organs begin to burst. this, however would not be a deterent since, as i have said before, zombies feel no pain. this might only help to slow a zombie down, as now its body is no longer in its best condition.

on fighting back:
as far as one's physical prowess goes, one should keep up a general exercise regiment. though there are not necessarily zombie outbreaks imminent, one should be prepared for the worst.
i'd say the best kind of physical training you should go for, as long as time and ability do not interfere, would be boxing, swimming, martail arts, or some form of gymnastics, all of which work the body in full. however, and this is a big however, for those that go for the boxer or martial artist's build, DO NOT become overconfident and then think you could fight a zombie in hand-to-hand combat. that should be the absolute last thing on your mind. unless you're a shoalin monk and could just punch through a zombie's head, you're pretty much gonna be up shit creek if it comes down to a physical fight. weaponry is your friend.
firearms are great. you should get them for fighting zombies. but don't go full auto, you'd simply be wasting bullets. you need accuracy, not quantity. also, shotguns may be great for presenting a wall of fire to knock down a number of marauding zombies, but this is only in close quarters. as distance increases, accuracy decreases.
always carry a bladed weapon. remember, blades don't need to be reloaded.

that's all for a starter. if you have specific questions, please feel free to ask.

reprazent.