I just wanted to throw up the routine that my personal trainer has me on for you all to take a look at.

1. warm up on the treadmill for 8-10 minutes
2. stretches
3. a mini-circuit with bridges (planks) and cobras, then crunches on a ball (3 sets each)
4. a main circuit of consisting of: either dumb bell presses or dumb bell flies on a ball (chest), lat pull down or back rows (back), shoulder press or scaptions (shoulders), dumb bell curls or hammer curls (biceps), tricep extensions on a ball (triceps)
5. a lower body exercise doing ball squats, lunges, or squats on versa disks
6. cool down on the treadmill

I've been doing this for close to two months now. I'm getting stonger and I do notice some slight muscle definition where there wasn't before. The only thing I need to work on now is ironing out my diet. That's been the toughest so far.

if your goal is gaining muscle then i would drop the ball and use a bench (more load)
if its just general fitness then you can keep it in although IMO its just a pain in the arse.

also i would save the stretches for after the workout,you have done a warm up that should be enough,static stretching a muscle before lifting can sometimes do more harm than good.

The reason why he's got me using the ball is to help with my stabilizers and balance.

Something that instantly jumped out is your lower body work at the end, and the core work at the beginning. Performing that little core circuit is likely to tire your core and inhibit your ability to really kill it during the main circuit.

When i structure circuits, I usually work largest to smallest (IE: Legs, back, chest, shoulders, core). Ask your trainer why he structured it this way, he may have a very real, very legitimate reason.

I agree with what both Buzz and Adler said in that I'm not a fan of performing strength exercises on balls and I'd always put the big money movements first.

However, having said that, he's included a horizontal press and pull and a vertical press and pull along with lower body work like squats so it looks well structured to me

Why don't you guys like working on the ball?

many reasons, you cant use as much weight,if your on your own how do you get the bar into position,there are much easier ways to work your stabaliser muscles,etc

The ball is good! Use the ball occasionly mixed in with your training or for a couple of movements in a session. The ball is a fantastic tool in training and you can still get big on the ball if you are doing the right things.

I'd agree the occasional ball work can be a good suppliment, but I don't agree that you can still get big on one. I've never seen a big guy use one, just the 180lb Mens Health cover model wannabe's who look they could do with a good meal

I guess there's probably a good reason why I'm on the ball so much. Then again, I am only about two months into this. Right now I'm not necessarily worried about getting 'big' as I am with losing weight and getting some definition.

Yeah, your PT can see you in person so can make a more accurate judgement of your needs than anyone here can. It does look like a pretty balanced routine so you should see decent gains

Good luck