The widespread preoccupation with physical fitness--which got harder to ignore when running became "jogging" and now results in the promotion of pricey designer "activewear"--has crept into yet another facet of life: corporate conventions.

If Washington Tennis Services has its way, no longer will a golf cart cruise constitute the predominant physical exertion at a typical corporate gathering; executives may be competing in prepackaged tennis tournaments.

Washington Tennis Services was founded 10 years ago by local tennis instructor Gary Henkin to provide more tournament competition for students. Henkin is still president of the company, which has now placed tennis "teaching pros" at about 150 private clubs in 30 states.

Washington Tennis Services' hotel recreation and marketing division is currently promoting the sport as a way of attracting business to hotels. Its marketing plan is aimed at hotels interested in luring tennis buffs and centers around the same concept as that of the parent company, except that its teaching pros are placed at hotels rather than at clubs.

Division executive vice president Fred McNair--who was ranked No. 1 in the world in men's doubles in 1977 and represented the United States in Davis Cup play in 1976, 1977 and 1978--said expansion of the company's tennis services to resorts will succeed because "recreation has become such an integral part of the amenities" offered to a hotel's clientele.

"We provide the personnel and programming--packaged, specially designed clinics for tennis and racquetball, an organized program with lessons and special clinics like doubles tactics and strategy sessions" and conduct tournaments designed to fit the groups attending, McNair said.

WTS trains and certifies its instructors--all of whom have had prior teaching experience--during a 20-hour business seminar at the Linden Hill Hotel in Bethesda. Instructors pay a one-time fee to be schooled in administration, management and public relations, then go on the WTS payroll. Hotels pay WTS for the instructors' services.

Henkin says that this training is the key to his company's success.

"The reason we've been successful is that our pros know how to conduct themselves as businessmen," Henkin said. "The seminars, which are unique to our company, probably touch the weakest area from a tennis pro's standpoint, being able to conduct himself in a business-like fashion from day to day, knowing how to open a pro shop and what to do with the goods, how to promote programs."

Henkin said the company has recently formed a new "racquet sports development" division which provides instruction and management services to commercial courts that are open to the public. He said the division now has "a couple of indoor clients," and has created "substantial interest" among potential clients.

Washington Tennis Services also publishes a newsletter called "Profiles," which McNair said goes out to about 2,000 tennis club managers and owners. This mailing list is an important selling point for the hotel division, he said, because it shows resort owners that Washington Tennis Services has exposure among the people who might be inclined to play tennis during their vacations or conventions.