Athens exposed.

The Olympics return to Greece in almost all their glory on Friday, August 13. Spectators pining for prolonged peeks at nude physiques will have better luck visualizing The Naked Olympics (Random House, $12.95), in which Tony Perrottet reveals the ancient naked truths;

* The Greeks themselves were unsure how their habit of naked exercise began. Some thought it started when an athlete tripped on his loincloth; others thought it began when a sprinter found he could run faster naked. Although the habit probably originated with initiation rites, it suited the vanity of Greek athletes--Narcissuses all, who paraded themselves like peacocks for the crowds in the Olympic Stadium.

* Only men and boys could enter the ancient Olympic Games; women athletes had a separate festival dedicated to the goddess Hera, where young virgins raced Amazon-style, in short, tunics with the right breast exposed. (This reflected the legend that Amazons cauterized one breast so as not to interfere with their javelin throws.)

* While athletes were waiting in the tunnel to enter the stadium, they would scratch lewd graffiti message to one another on the stone walls, probably with the tips of javelins. Examples survive at Nemea: "Akrotos is beautiful", writes one. "Says who?" asks another. "Look up Moschos in Philippi--he's cute."

* Many Greek trainers railed against the debilitating effects of sex during the Olympics. In the sole surviving training manual--Handbook for a Sports Coach by Philostratus--the author indicates that athletes should sleep with flattened leather plates over their loins and suggests special workouts for those plagued by "habitual nightly emissions."