Sportsmen who engage in sports in open natural settings are not always coherent in their behaviors towards environment; in fact, they seldom are. From survey made on a sport event the "Grand Raid 2010", a foot race in mountains of R�union Island, the authors discover that these sportsmen are not the good activists fighting for a green planet that they imagine they are. The authors try to explain the disparity between the perception that they have of themselves and the reality of their practices.