Drawing on feminist, critical, and poststructural theories, the purpose of this research was: (a) to understand fifth-grade mestizas self-identified barriers to physical activity, and (b) to work with them to develop strategies for challenging these barriers. Data were collected over the 2005-06 school year. Our interpretations are divided into three sections: (a) the barriers the girls identified to their physical activity participation; (b) how we worked with them to study their primary self-identified barrier to physical activity--"the boy's won't let us play;" and (c) how we refocused our research to help the girls publicize their barrier to challenge the inequities in physical activity at their school. (Contains 3 figures.)