This study aims to determine the level of flexibility of PNF stretching. Where this research was carried out at public senior high school number 8 Pontianak. The research method used in this study was an experiment using the One Group Pretest-Posttest Design. The sample in this study used PKO students at Tanjungpura University, semester one, as many as eight people. This research was conducted by measuring the sit and reach before and after jogging 2000 m, then giving the PNF stretching treatment; after being given the treatment, the sit and reach measurements were retaken. Data analysis techniques using descriptive and t-tests. The results showed a difference before and after stretching the PNF; the average of the people who tried before stretching the PNF was 11,98 cm, and the average after stretching was 14,70 cm. So it can be concluded that PNF stretching can increase flexibility.