IS there any criteria to decide whether to fight your rival from distance (by using kicks for instance) or to close distance and to fight back with short punches for instance? Does it relate to differences in size between you or any other difference?
Ranging in self defense is actually very different than sparring or competition fighting.
Start with this: what range are you at when you realize you're being attacked? (and don't have an option to get away?)
Are you 20 feet away, with them running and yelling at you? Did someone tackle you from behind and you're on the ground? See, the first problem is that you don't necessarily get to choose the range when you're assaulted.
The second question is: what is the terrain like?
You can't play a distance game if you're attacked in the elevator, or when you're halfway in your car.
Those two questions make a lot of the decision for you. If you get any option beyond that, then the questions are: what is open and where do you feel comfortable in your techniques/methods? What is going to make you safer given your options?
You can find video of folks holding off knife attackers by putting their shoes on their hands, and holding them off long enough the attackers decide to leave before the cops show up. You can find video of women doing great judo throws of guys who outweigh them and leaving the guy completely knocked out from the throw. People defend themselves successfully at all ranges, and it has to do more with their ability to adapt to the range they find themselves in and the training they've had.
This is why a lot of self defense training ends up having you train many scenarios from different ranges and starting points of disadvantage. It's not like a match where you see your opponent, you know what they're armed with, you know there's no other people about to run in and attack from behind, and you don't have to worry about tripping or falling down stairs or anything.
- I would say it depends on the attacks of your opponent. As I assume that you would not attack anyone.
- It depends on the size of your opponent (if he is much bigger, it doesn´t make sense to kick and use the distance game)
- It depends on the surroundings (Bar, Open Range, Wet, Swimming pool, Train etc.)
- It depends on if your opponent has any weapon (Knife, bat, Chair, Stone)
The best advice i can give you is to use the right tool for the right distance. by that I mean if you are in Leg-range simply use your legs first (attention that on the streets high-kicks can be contrary productive), if the opponent comes closer in punching range use the fists. If still coming closer use elbows, headbutts, knees what not... If on the ground, use grappling skills like arm bars, locks, chokes, from eye gouging to biting.
This depends on many factors. If you are super athletic but not very strong, and you are under attack from a human tank, then your best bet is to keep your distance and wear them down (actually your best bet is to just run, but I'm assuming in your hypothetical scenario that's not an option). On the other hand, getting in very close makes it easier to to use throws and takedowns, and if you know what you're doing, there are some awesome strikes available at close quarters.
I don't think there is a single right answer. It depends entirely on the situation, and you. I'm quite big and strong. But I burn out quickly. So my general preference is to close the opponent down, moving in close and fast. When I was young, I was light and weak but very fit and fast, so I'd stay out of the way and choose my moment.
All that said, I think there is argument for both ranges for anyone. I prefer very close, but if my opponent makes a mistake while at the longer range, and I think I can take advantage of that with a jumping kick or step in kick of any kind, I will take it.