Well, I decided to work on it 2 1/2 years ago when I decided not to turn 55 fat (205# at 5'8") and out of shape. So I lost 40 pounds by laying off the carbs. I started working out on weights, slowly building up, and did a lot of back, shoulder and upper arm work with plenty of reps and sets to build the ancillary and support muscles, and to focus on the back tension muscles. After I lost the 40# I started running with my dog. She is great running buddy, and keeps me on pace, as she hates to slow down.
Now, 2 1/2 years later, I have my old college body, (but not the hairline). Things hurt more, but I can run 7 miles in an hour, bench press 220#, do 40-50 pushups, 20-30 dips, and pull the 100# right-arm bow-pull on my cable weights.
So, now I can string and shoot my Howard Hill 85# Wesley Special - easily and accurately. The 70# bow is a light bow now.
And, I feel great out hunting.
This is not bragging. Anyone in good health can do it. It's just to show what an old duffer of 57 years can do if you just start making a little progress every week, working on yourself so you can enjoy archery and the rigors of hunting the hard way with the younger guys.