hiking poles?

take some glucosumine... everyday during a hunt....advil...

certainly resting/recovering prior to a hunt could also help, not working out right up to the date, let your body recover a bit prior to the hunt, perhaps a week or 2 before.

a lighter pack wouldn't hurt...and/or training with a pack with weight, or losing 10lbs or more before a hunt. less weight/force you can have banging on your joints the better.

good luck!