I really want to gain strength in my upper body, and get more toned, but I have a problem with tendonitis from my elbows to my wrists. I'm doing some strengthening of my forearms to try to help, but is there any way that I can work my upper body without stressing my wrists? Thanks!

You can try using wrist staps....http://www.bodytrends.com/miscimages/rrprostp.jpg
With time you will get stronger though....