I'm overweight. I have been for almost 15 years. This last year I've dropped about 30 pounds and still run close to 6 miles a week. This is not too brag but to encourage anyone else on this forum, I've been to meet & greets so you know who you are, that may need some push.
Here's what I've been doing and it's mostly to try and help with USPSA shooting. Either a 5lb kettle bell or dumb bell but hold it in front of you using the same sight position that you would your pistol. Hold it for 10 seconds and back down. Also, the one thing I hate that's helped the most is crunch's. Getting my core strength up has steadied my hands.
I hope this is what you're talking about and I didn't derail.