Last summer Peter Manning sent his son Theodore, then 6, to a day camp that turned out to be "too domestic," in the father's view. "They were inside about half the time," Manning said, and Theodore had as much energy when he came home as when he'd left.

This summer the Mannings decided on something a little more demanding. So Theodore trooped off to Valley Mill day camp in Germantown, where the highest honor for a camper is to be judged "hard core," the kind of kid who "sleeps in the prickers in the rain."

These evenings nobody has to rock Theodore to sleep.

"They bring him back in the bus," Peter Manning said. "There's nine kids in there and they all look about the same. They have on two pairs of pants and no shirts, they're covered with mud and scratches. He walks in the house and falls on the floor."

The elder Manning was at Valley Mill last week for boys' parents day, when grownups get a chance to try stuff the kids exhaust themselves on all week. It was funny to watch sophisticated Washingtonians nervously hugging the shore of a two-acre pond in skittish kayaks while their 10-year-olds showed off racing skills and Eskimo rolls, looking as confident as Alaskan hunting guides.

Valley Mill is, according to director Tom McEwan, "an old-fashioned outdoors camp," where the 350 campers get wet when it rains and muddy the next couple of days. There are no Pepsi machines, computers or pool tables. There are plenty of kayaks and canoes, horses, trees, trails, leaky tents and some prodigious stands of poison ivy.

"You should hear some of the phone calls we get when we send home the parental permission slips for our rapids-swimming trips," McEwan said.

The parents can't believe anyone has the nerve to run a crowd of prepubescent city kids through Potomac whitewater in a raft, let alone on their backsides. But that's one of Valley Mill's time-tested adventures.

"We take them down the Maryland chute at Difficult Run," which is halfway between Great Falls and Little Falls, said trip director Andy Bridge, like McEwan a former member of the U.S. whitewater paddling team. "The worst injuries we get is when the kids scrape their legs on the rocks running back to the top to do it again."

The point of rapids swimming, Bridge said, is to acquaint youngsters with whitewater so that later, when they go paddling through rapids, they aren't afraid of falling out of the boat and know what to expect if they do capsize.

It's important, he said, because kids who get good at paddling at Valley Mill may end up at age 13 or 14 tackling demanding rivers like the Youghiogheny at Ohiopyle, Pa., the Cheat in West Virginia or Little Falls in Washington, on supervised weekend trips sponsored by the camp. Advanced paddlers in camp regularly work out in the S-turns and at Rocky Island below Great Falls and some, such as 15-year-old Joe Jacobi and 16-year-old Erik Schumann, already are competing at the national level.

McEwan, 39, brother of 1972 Olympic whitewater bronze medalist Jamie McEwan, said paddling slipped into the program at Valley Mill about 23 years ago when he and his mother, who helped found the camp in 1955, grew interested in the sport.

Although he said whitewater is only a part of the outdoors recreation program, McEwan agreed it makes Valley Mill unique. In addition to its 60 acres of woods just north of Potomac, the camp by virtue of its boating program uses close to 75 miles of Potomac River from above Harper's Ferry, W.Va., to Washington.

McEwan invited me to join a camp paddling trip. Since I have mastered only the first half of the Eskimo roll, the part in which you tip over, I opted for a picnic and canoe voyage up Seneca Creek to Poole's Store with a group of 7- and 8-year-old girls called "the Squirrels."

"Are we there yet?" asked the Squirrels as we pushed off the rocks at the start.

"Are there alligators here?"

The Squirrels don't do much paddling but they were properly fascinated by the turbid brown water that rolled downstream, the product of a previous night's rain, by the green heron and the cardinal that skittered across the water, by locals fishing for catfish from the shaded bank, by teen-agers swinging from tree-ropes and plunging into the deep holes, by the curious sickly bark of sycamore trees and by the fat snake that slid off a branch and plopped in the water as they rounded a bend.

Then at Poole's Store, the Squirrels all jumped in the creek and got properly muddy for the ride home.