This Critical Comparative Content Analysis employs theories of poststructuralist feminism to examine two versions of a nonfiction fitness text for young adult readers, one written for females and one for males. The analysis reveals the persistent naming of gendered assumptions about the appropriateness of particular sports to particular athletes, purposes of fitness, understandings of the ideal athlete, and emotional capacity of young adult readers. These assumptions result in regular and repeated performances of gender that have the potential to suggest to readers that there are certain expectations around fitness that depend upon whether an athlete is a girl or a boy. Taken together, they reflect a particular positioning of athletes and expectations around performance, suggesting to readers that how bodies are shaped and how bodies perform are normative and distinctly gendered, a finding that holds particular resonance when we consider the authoritative nature of informational texts.