I just wanted to add a couple of things to Adam and Sean's excellent responses.
I want to give a bit of perspective to your categories of fights.
What you refer to as a schoolyard fight I refer to as
Male Hirearchical Fighting.
This type of fighting includes anything from actual "schoolyard fights", usually involving inmature males, some name calling then the violence.
It also covers the typical "barfight", usually involving some sort of verbal attack preceding the actual clash.
Hierarchical Fighting also covers the more "honorable" subsets of "Dueling", an old custom that uses a violent act to redeem some sort of offense to one person's honor, and "sportfighting" which covers the entire gamut of combat sports.
And, before anyone feels excluded (read fraternity vs fraternity fights, gang fights, rumbles), it includes ANY variation of the above themes.
The common thread in all of the above manners of fighting, and the reason they all fall in the same category, is that the all involve:
A)Consent- Both participants have voluntarily agreed to commit violence against one another. Or both actively participated in the circumstances and chain of events that led to the fight.
1.Someone insults you, you insult them back, then someone says "lets Go!" and violence ensues.
You can use your imagination here, this could happen at a bar, schoolyard, or even with your neighbors.
2. Two professional fighters agree to fight under a certain set of rules.
B) Preparation- There is a certain amount of time between your awareness that violence is coming and the actual violence. This could be as short as the verbal exchange or trading of insults, expletives, or justification, in the case of school or bar fights; or as long as several weeks as in the case of professional fighters.
C)Ego- All Hirearchical fighting is based on establishing dominance or superiority over another human. In a barfight it's about showing who the "alpha male" is. In professional fighting (although there are many positive lessons to be learned from sportive competition) ultimately there is pride, fortune, and fame, all related to ego.
It's important here to note that Hirearchical Fighting can be very dangerous and even result in death. However, it's most important to know that ultimately it is YOUR CHOICES (in barfights usually a lot of bad ones) that lead you to be involved in this kind of fighting.
To avoid this kind of fighting simply involves making better choices.
This is one of the things that will be looked at very seriously by a judge or a jury when deciding if the force you use was justified.
You must deeply introspect on this. Even if you could win the fight or be acquitted in court; how many fights could you avoid simply by doing some proper intelligence and advance work on where you are going to have your next beer. Learning how to read a room and body language to recognize who the "bad people" are and who they are with.
How many fights can you avoid by learning and using proper defusing tactics?
The level of force is not what makes the difference in classification. Its the circumstances precceeding the fight that do.
You can have Hirearchical Fights in a schoolyard, a bar, a ring, or on the street; but remeber, you can also be ambushed there. Prepare accordingly.
Blauer Tactical Systems