Crackdown 2

These little sods are a pain in the backside...

It's worth noting that there are different levels of renegade orbs as well, so there's no point in trying to catch a level 6 agility orb if you've only got L2 agility!

They seem to have relatively fixed paths though, so once you've chased them for a little bit, you should start to get an idea of where they'll be going next, and if it's at a corner, that's where you can catch up with it.

For AR orbs, I found that sometimes you could get them to a point where they can't go left or right because you're kinda midway between either point for them... if you can keep yourself on that vector, you can walk right up to it without it even being able to move away (not the best explanation, but when you get them to a corner, you'll see what I mean, you can step left and it'll move right a little, and you step to the right, and it moves back to the left :) )

Also, once you have your agility high enough that you can move faster, sometimes jumping over it's path and doing a ground-strike allows you to drop down on it before it can move out the way...

With DR orbs, use the supercar so you have a chance of catching it, and remember that while it follows a fix path, you're free to roam over the surrounding area, cutting corners (and civillians) to cut it off...

These orbs travel in a set path. It helps to have your agility up to where you can jump 25 feet to attempt to get the moving agility orbs. You will be fast enough to catch up with one and you will jump high enough to get some of them in the beginning.

You will find a Renegade Agility Orb in the docks area in the beginning of the game. The announcer will tell you to catch it. Simply follow it around see if you can memorize its path, then cut it off to acquire it. You will get a good deal of Agility points and the achievement.