Nikon d5100 sport pictures?

So I have a horse show this weekend and wanted some good pictures. I have the nikon d5100. I'll be doing fast paced events like roping, barrel racing, flags, stuff like that. I want my horse and I to be in focus and it doesn't matter about the background. What setting should I put it on and what stuff should I adjust? I would obvisouly put it on sport but should I change like the ISO? Or anything else? I know someone's going to say read the manual and I have. I haven't had the camera that long so I haven't had the chance to play with it at rodeos or anything. Thank you!

Added (1). Thanks guys. We're going to be inside with dimish lighting. I'm going to play around with different settings and what not for poles while I take pictures of my friend. I'm going to be having my mom take the pictures while I'm running so that's another reason I wanted to find a good setting because she's not 'camera smart.' although I'm not either. I don't run super fast patterns since my horse is older but I still do decent times, enough where there's a blur.

Hi
I have the same camera for like a year now!

I prefer go to Manual mode "M"
Now you can Optimize Everything and The Shutter Speed!
if you use Lower shutter speed you get Blurry shot
and if you use high number of Shutter speed you Can Freeze the Action!

Set the Aperture by holding the button that is behind of Shutter Release (Right One)
hold it and use Dial to set it to 7.1 or 8!

you can set the shutter speed just by dial and you get what to use in Experience!

in manual mode you should check the meter of light or Light-meter (it's like a ruler)
when the moving object is in the middle your shot will be exposed well so by Controlling the Shutter speed and ISO you'll get a Exposed shot!

Now Push the " i " Button in Right side of View Finder
First One: If you edit pictures in photoshop use Raw but if you don't Jpeg or JPG is enough

So Set it on Fine!
Second One: Set it on Large if you want more details when you're zooming the picture!

WB: set it on Auto White Balance (it's enough for now)
ISO: you get it in Experience

and the important one is this one: Set it on Continuous (you can hold the Shutter button and camera does the shots as long as you hold it!

I think now you can get the Shot you're looking for
sorry if it was this long i didn't know you Knowledge in photography so i explained everything!