For the first few days after getting out of the hospital, I did only less strenuous things like arm curls, triceps, pulldowns, walking. The next few days I ramped up and started doing everything except strenuous whole-body stuff at my usual weight, which went well. In week 2, I did everything except ab work, and did less weight and more reps in anything major (like leg presses) that might stress the diaphragm or abs. Saturday I did my first direct work on abs -- Nautilus pullover. My usual weight on that is 230#, so I tried 70# -- like no weight at all. Then tried 160# -- oops, three reps and I could feel a little tug in the area. So backed down to 115# and did 5 sets of 40 reps (usually do 25 or so.)
No untoward effects from that effort, so after two days of other things I returned today to abs and did weighted leg lifts (the "Ab Flexor") -- I usually do 5 sets of 30 at 120#. Since you are lifting your legs as well as the added weight, I thought I'd try 60# -- nope, felt a pull. At 40#, though, I was able to do 6 sets of 20 reps.
The concern here is that excessive stress will tear internal stitches apart. I try to approach this slowly and carefully -- sudden moves greatly increase peak strain -- and back off if there's any sense of stress. So far so good.
I'm back to running at the usual speed and slope, and I no longer feel any pain jogging down the hill.
Since I can't do abs, I'm not doing deadlifts either, since I don't want to have the lower back muscles too strong when the abs can't counteract them. Next week.