Nothing, (physically).
I'm jogging 15+mi./wk. right now....and weight training 3X/wk. I'll be ready....as I haven't been in better physical condition in years.
I actually haven't touched my bow in quite some time....but I'm beginning to feel the urge. The layoff has served me well. I'll be ready, come opening day.
If anything....I need to complete my equipment inventory and get my hunting arrows prepared (which I've already set in motion - Thanks, txjourneyman

).