Every hunter needs to get in shape for the season, but running and the other standard exercises do not adequately develop the specific muscle groups that are called upon in the field.

Or so says Dr. F. Latt Rajectory, a specialist in this long-neglected branch of sports medicine. "Take your deer hunter and your duck hunter, for instance," he said. "They have little in common, truly, although both spend long hours of waiting followed by strenuous activity. I've buried many a hunter because he set himself up all wrong for his particular sport."

Rajectory, a sinewy whippet of a fellow, hunched forward on the executive stool in his office at Sports and Stream magazine. "Terrain!" he ejected. "The difference is in the terrain. A boxer trains in the ring and a runner trains on the track. A hunter should train in the field, with the clothing and equipment he will be using during the actual chase. It's all in my book."

The book is The Healthy Hunter, published by Nature Rifling Association Press ($30.30). The following excerpts are quoted by permission.

DUCKS AND GEESE -- Before sunup, carry a narrow board and two cinderblocks about a mile into a marsh, preferably in a cold rain. Find a spot that's good and gooey and balance the board on the blocks so that it teeters and also almost collapses in the middle when you sit down. Set a tightly wound Big Ben alarm clock to go off in about two hours and place it under the board where it cannot be seen.

Scan the sky thoroughly from horizon to horizon until the neck begins to stiffen. Gradually slow the scanning rate, let your head droop, and doze off until the alarm rings. Jump up and sprint through the marsh until it gets too deep to run in. Press forward until water slops over the top of your waders. When they are full, drop your hat and wade in widening circles until you no longer can see it. Wade in gradually decreasing circles until you find hat. Return to board and repeat until sundown.

DEER -- Go by Southern States and buy a hundred-pound sack of feed corn. Put it in the trunk. At 2 a.m. the following day drive to a thick, hilly patch of woods. During the trip leave your flashlight on until the batteries grow weak. Follow a game trail until the flashlight goes out, choosing the uphill path at each fork. Stumble around until it grows light enough to pick out a tree you can just barely climb.

Climb it and choose a fork you think you can sit in for six hours. Try to do so. Wait until a buck comes along (he will come along, because it is not hunting season). Take a long, careful look at him, because you will never see him again. Then climb down or fall out of the tree and try to find the car.

Take the sack of corn out and drag it to the tree you were sitting in. Rest 10 minutes and then drag it back to the car. Give it to a friend who hunts geese.

DOVES -- Go to a skeet range. When your turn comes at each station, stand with the butt of the shotgun on the ground and a can of beer in your trigger hand. Tell the man to pull when he pleases.

WOODCOCK -- Find a brier patch in boggy ground. Walk into it briskly as far as you can go. Extricate yourself and repeat until your pants become shorts.

QUAIL -- Take your dog into the country and turn him loose. Try to find him.