James E. Strates Shows, a modern carnival, has a dozen or more machines designed expressly for the improvement of the human condition.

The machines--the Pirate, the Enterprise, the Loop Looper, the Tri-Star, the Sky Diver among them--have the sole purpose of turning a person upside down and inside out.

Carnivalphiles now recognize this as a necessary aspect of the scheduled summer maintenance of humans: carnival therapy. During the winter months of inactivity, they reason, all the little inside parts that make us go--bones, joints, tubes and such--settle down like Cheerios to the bottom of the box. When your feet swell up in summer, it is because of this phenomenon, and a carnival is indicated.

Recommended treatments of the James E. Strates Shows:

* The Enterprise. A new machine built in Germany, composed of a circular base from which pods invitingly dangle. When the pods are loaded with humans, the whole circle rises on its side and hurls them around and around. Better than tetracycline for incipient or lingering malaise.

* The Pirate. This ride costs $550,000 and is a new addition to the Strates midway. It seats 53 persons in what appears to be a large boat. Just when everyone is relaxed, steel restraining bars snap over your lap and the boat commences to swing like a pendulum through 180 degrees. The gratifying sense of weightlessness at the apogee may or may not cure baldness, but it does make whatever hair you have left stand on end.

* The Tri-Star. A three-pronged assembly with seven pods dangling from each prong end. At speed, the entire affair rises up, stirring the human Cheerios in their boxes and bringing to the lips of unbelievers testimony of new beginnings.

* The Loop Looper. This appears to be a large wheel standing free in the middle of the carnival. Inside it rides a single large car. When loaded with people, the car rolls back and forth like a loose ball bearing until it finally achieves the momentum to reach the top, at which point it stops, for five seconds, to allow the riders to dangle upside down from their seat belts. This is very good for your stomach, and also relieves the pressure on the bottom of your socks, which is, after all, what wears them out so quickly.

The Sky Diver. Although newer rides have snazzier artworks and can seat more patrons, many carnival-goers recognize the Sky Diver as the ultimate form of therapy. It stands vertical, like a Ferris wheel, but has cabs that are enclosed with wire and are free to swivel on a fore-and-aft axis. The swivel is controlled by a steering wheel. By skillful use of said wheel, the rider, with practice, can not only go straight down while upside down and reversed against the centrifugal force, but continue upside down through the loading gate area.

The James E. Strates carnival, which requires that its employes have short hair and no beards and is freshly painted to make a good impression because "first impressions are important," is run by E. James Strates, 52, an ex-Marine whose father, James E. Strates, founded it.

The show, which wends from Orlando, Fla., to Connecticut, has 43 different rides and sideshows, and will be at the RFK Stadium area off Benning Road through June 19. It is making money. Last year its gross was up $400,000, despite the recession, and as a result E. James Strates drives a brand-new Mercedes-Benz. His business theory is "Entertain the people," and his motto is "This is the Good Carnival," and his nickname is "Boss," which comes naturally to his employes, he explained, because he is, indeed, the boss.

E. James Strates' son, James E. Strates, 21, is a Marine aviator candidate who has just begun training at Pensacola, Fla.

"They took him up last week and he flew upside down," his father reported. "He called me to say he loves it."