"Coach," now at a few area theaters, is thin as a wafer yet consistently good-natured.

The screenplay by Stephen Bruce Rose and Nancy Larson attempts to sandwich a lightweight chronicle of a high-school basketball team's turnaround from chumps to champs between equally lightweight layers of feminism and eroticism.

Cathy Lee Crosby is cast as a vibrant woman athlete, a former Olympic sprint champion no less, who is hired to coach a talented but directionless boys' team at a title-hungry suburban institute of learning, sports and horseplay. She comes through with flying colors, despite the minor complications posed by a hostile board member, Keenan Wynn, and a love affair with her best guard, Michael Biehn.

The movie never takes a realistic humorous approach to the idea of a woman coach's inspirational effect on a team of teen-aged boys. For example, the romance between coach and player represents a clear sacrific of the laws of probability to the whims of sex fantasy.

Crosby looks so beautiful and healthy and projects such easygoing yet intoxicating sexual warmth that you realize how much more amusing it would have been to shape the story around the devotion she inspired in every team member and the ways she handled her lovesick proteges. The mildly racy romantic idyll in "Coach," a PG movie, has credibility only because Crosby and Biehn interact and improvise attractively, whatever the excuse, their sexual rapport looks authentic on the screen.

Crosby projects a palsied sort of sexiness that recalls personality attributes that once endeared actresses like Patricia Neal and Angie Dickinson to moviegoers. It's obvious that her wide, brilliant smile and husky, cheering laugh could radiate beyond a trifle like "Coach."

Biehn, whose clean-cut good looks might make him a better candidate for Luke Skywalker than Mark Hamill right now, seems especially amusing and inventive in romantic scenes. He's a playful, enjoyable cagey suitor. When he finally takes the liberty of kissing Crosby and then departs happily exclaiming to himself, "I kissed the coach!" his exaltation is inhesistable.

Movies like "Coach" frequently turn out to be valuable auditions for young performers. Biehn tops a list of unknowns whose looks and skills may eventually make them better known: David Walker, Meredith Baer, et al. Walker, a tall, gangling young actor, becomes the principal source of sporting humor in the story. As the team's center - an unaggressive, unrefined raw talent - he goes around in a daze until being placed in a trance; desperate to exploit his ability, Biehn and fellow guard Clarkson hypnotize Walker into realizing his potential.

One couldn't call Bud Townsend's direction flawless, but it is spirited and resourceful. For example, it appears that about half the footage was shot in the confines of a high-school gym, but Townsend manages to keep a limited number of extras reacting spontaneously and the game situations flowing dramatically. There's a very witty slow-motion payoff at the close of the big game, when Biehn's deciding free throw rolls around and around the rim. For the purposes of movie suspense, it's a highly educated ball.

Personally, I found "Coach" a far more satisfying light entertainment than "Grease," which is essentially a B-movie high-school programmer that happens to be suffering from a Napoleonic complex.

"Coach" is better cast than "Grease" and treats its performers with more respect. They may not be playing major roles in a major enterprise, but their efforts aren't obscured by a bloated, overbearing filmmaking machine. "Grease" draws millions on the new-minted stardom of John Travolta and then butchers the few opportunities he has to make a sustained impression while singing or dancing.

"Coach," of course, never aspires to the same moviemaking or profit-making league, but it shows far more evidence of fundamental moviemaking ability.