Lisa Jaster is a United States Army Reserve lieutenant colonel and engineer officer who was the first female reserve soldier to graduate from the Army's Ranger School. She completed the training, which as many as 60 percent of students fail within the first four days, after "recycling" through, or retrying, several phases of the multi-locational course. Due to being recycled, she was at the school for six months; the school takes a minimum of 61 days and includes up to 20 hours of training per day alongside a strict diet. She graduated at age 37, while the average trainee age is 23.