They subject themselves to additional regulations and medical screenings to participate in school sports. "Somewhat like adults who choose to participate in a 'closely regulated industry,' students who voluntarily participate in school athletics have reason to expect intrusions upon normal rights and privileges, including privacy."
Participating in school sports requires students to comply with additional regulations and undergo medical screenings. This is comparable to adults who deliberately work in a highly regulated field, suggesting that students participating in school athletics should anticipate some limitations on their personal freedoms.