Nature essayist Janovy (Keith County Journal, Yellowlegs) here directs his hard-working (the strain shows at times) sensibilities towards the mysteries of a human activity, sports--specifically, his daughter's athletic prediliction and prowess. A trained biologist, Janovy emphasizes heredity over environment in his quest to discover why daughter Jena--or anyone--plays sports. Beginning with ""Indications,"" he traces Jena's athletic development from age one--""there were indications she would be 'coachable'. . .there were indications she would play at top speed""--to college. The propensity for athletics is, he implies, inborn; in Jena's case, however, also inherited is another ""indication"": that ""she would be small. We called her Peanut. . ."" Jena's seemingly genetically endowed competitive drive (which Janovy looks at via Thomas Kuhn's model of humanity as a puzzle-solving species), intensified by her need to compensate for her small size (a handicap that, in time, prevents her from turning pro), results in a budding athlete ready to be molded by environment. Enter the coaches, to whom Janovy sings a maudlin paean (""Thanks, coach; it's been magnificent"") throughout the book--a not surprising turn since Janovy is a teacher by trade, indulging in magnificence by association when he writes of a coach that ""you must do the hardest thing of all--you must teach."" And teach the coaches do, instructing Jena in one sport after another--volleyball, baseball, basketball--detailed in prose usually clean and swift, but sometimes stumbling as Janovy attempts ""to match the structure of sentences and paragraphs with the timing of a game,"" a well-intentioned experiment often reaping lumpy, awkward results: ""whistle, ref, direct the spherical traffic; I serve; the point is ours. . ."" (volleyball). Janovy offers some fresh insights into sports' biological underpinnings, but he stretches for most of them and for his parallels between athletics and life-at-large. This overreaching, plus his frequent driftings into proud-papa mawkishness, add up to an unusual sports book that deserves a cheer for effort, but fails to win the trophy.