I am not very good at the Plank apparently. Well, I take that back. I can do the normal plank. It's the elbow plank that I suck at.
Before bed, I did 2 of the elbow planks last night and my back hurt on both tries. I don't have a mirror so I can't really tell if I'm sagging or not. And it didn't matter cause if I lifted my back, it still hurt. I could only hold the pose for about 15 seconds. I really pushed it and got 20 seconds on my second try.
Then I went out to my computer looked it up and decided to try the normal plank with my arms extended. I also did this on my bed so that I can look in the window for a slight reflection and see what I was doing. The extended plank was far, far easier (though I had to use my fists since I can't put any weight on my wrists at all). Then I did an elbow plank again... my lower back looks a little curved but I can't flatten it out any. Maybe that's because of my low core strength?
In any case, I did a few more and then I stopped. I already did 50 sit-ups on the ball before trying the plank. Tonight I will try it all over again. And then I'm sure I'll get lazy. *sigh* But the plank and then the side plank are on the workout sheet that I got from the NITRO meeting. Supposed to get up to holding it for 60 seconds. BS. I didn't even try the side plank yet. That'll be for about a month later (if I keep up the sit-ups and plank routine)

Maybe I should start out with just the sit-ups for now...