G'day
I get more aches and pains when I go coin hunting in parks, mainly from the constant kneeling down to locate targets, I try to just stoop over and check for the target but in the thick grass it sometimes is hard to locate the target so I have to either kneel or sit down to do it, detecting for gold is far easier on the back as you don't have to kneel as often and more walking is the best exercise for a bad back, also I would recommend that a knee pad be worn, there are many types available, knelt down one time without a knee pad and straight on to a sharp pointed rock that did some damage to my knee that took some time to come good again.
Always get the usual aches and pains on the first few days of a prospecting trip, leg cramps and muscle aches are normal for me but subside after a couple of days and by the end of the trip when its time to head home I am as fit as a fiddle, unless of course the gout kicks in
but that's a whole different story.
Gardening, mowing the lawns and walking are all good exercises to keep you a bit in trim, also trying to keep your weight down is helpful as well, I always shed some pounds during a bush trip as I purposely don't take any cake, ice cream, other crap that packs it on you when you are home.
cheers
stayyerAU