CrossFit Teens Portage CrossFit Is super excited to offer CrossFit Teens In Portage. CrossFit Teens is intended for teens ages 13-18. Class will last anywhere from 45 to 60 minutes. This session Will last four weeks and meet three days per week. CrossFit Teens is a core-strength and conditioning program designed for the teenage athlete. No two workouts are the same, and all workouts are scalable.