Your assignment, Runner, is to do your long run w/ an imaginary 13-year-old named Tristan. (Note to coaches: the persona of Tristan can be adapted to whatever level is appropriate for your athlete’s current fitness or understanding of training) Tristan is a middle school cross country runner in their first season. Talented for a 13-year-old, with natural endurance and enthusiasm for running. Tristan can hang with you, the more advanced/seasoned runner, on your very easy runs.