It is not what it seems
Having watched it on the TV, some of them can have the idea that to run in front of the bulls is quite easy, but, of course, it is not; ask the runners who have been running for years. You have to be very careful and keep an eye all the time, if you don't want to be badly injured; to run in front of bulls of 500 and 600 kgs of weight it's not a joke. Be sure that you will never feel the same sensation, but think twice before you run. If it's your first time, be aware of some details.
Advice
First of all, be sure that you really want to take part in the running of the bulls, don't do it just for fun or to appear in the TV. You will be thinking all the time about how will you appear on the News, or if your friends can see you, more than in the run.
If you have been drinking all the night and you are totally drunk, quite normal, don't run; it will be dangerous not only for you, but also for the rest of the people. You will think that you have all under control, but you won't; it is not that easy. If you have any problem you won't be able to react in the best way, because your reflexes won't be the same. So take it easy.
Usually the runners choose the same section to run and after been running for a while, they try to get out of the route without disturbing other runners or the bulls (which is quite difficult). You have to watch out for the run, it lasts only about 2 minutes.
Possible injuries
Most of the people who are injured during the running of the bulls, are because of falls while they are running or the blows they received trying to be as near as possible from the horns of the bulls. To nudge or beat the other runners is quite normal during the run. Some people say that most of the times it is because of the "divinos" (the people who prepare the run during the year), but other people say it is for the big quantity of people and the inexperience of most of them. It is true that there is a lot of people running, so is easy to understand that there will be fights, specially in some parts of the route; in Mercaderes and Estafeta, for example.
Sometimes, unfortunately, people die, nearly always because they don't know what to do, they don't know which are the rules of the run (that is what happened to the young American Mathew Peter Tassio, who died the 13th of July in 1995 ).
It is very important to know these rules to avoid these tragic accidents, as well as the route where the bulls run. If you have time, it would be a good idea to have a look in the section about the running of the bulls of this guide. You will find there the route of the run and the most dangerous parts of it. Be aware, you can be in danger anywhere, even if there are parts of the route more dangerous than others; Santo Domingo slope, Plaza del Ayuntamiento (there is no place to take refuge), Telefonica street and the Callejón (the narrow corral leading down to the entrance to the bullring), where there is a risk with the pile-up (not very frequently, the last one was in 1977- one person died and 35 were injured-)
Conclusion
Anyway, if you have decided that you will take part in the run, you could have a look in our "how to do the run" section, where you will find the basic rules of the running of the bulls. If you don't have time to read them, keep in mind, at least, this one: if you fall down don't get up, don't move and cover your head with your arms.
It will be better for you to run during the week, at the weekend there is a big quantity of people and it's more difficult to find a good place to run, and it is more dangerous as well.
Good luck!!!