Strength exercises for a cameraman

Hey guys I'm just curious exactly which muscles are being used when holding weight on one shoulder?

This is what I do for a job:

http://1.bp.blogspot.com/-7hs0tw2uk1Q/TjU6cuUERJI/AAAAAAAABFw/i67pPkGV7qo/s1600/shoulder_cam.png

I don't do a lot of shoulder shooting at the moment, but I will do in the future, and I'm wondering what I can do to build up strength and stability before I have to do it "for real".

A typical TV camera weighs between 8 and 12kg. Right now it takes a good while before my shoulder and back start to burn. However it is exaggerated when I have to get in a position less comfortable than standing up straight (crouching, half crouching, leaning forward/back, shooting at high/low angles etc). I already do a lot of core work outs but I'm hoping someone can suggest specific back/core exercises that will help out with endurance and stability. I'm new to strength training and only do basic stuff now, and I don't know anatomy well enough to identify exactly which muscles are being used.

Thanks in advance for any help you can offer

barbell row, dumbell shoulder, french press, lat machine.

i guess you need to train the very upper body so these exercises might help to build strength

Do you switch up shoulders? I would assume long time camera men run into some issues if they use the same shoulder all the time. I would not only work arms and shoulders I would also work on back muscles and core. You probably would be best of doing full body workouts or trading off days of upper body and lower body. If you're on your feet all day you're going to want to keep your legs in shape as well. Its funny to say but sometimes its easy to forget all of the body is connected and working together.