These young athletes were bound for stardom until a mysterious condition derailed their running careers

They were two exceptionally promising athletes, seemingly bound for track and field stardom, when their careers were derailed by a condition that doctors and researchers say they are only now beginning to understand.

They were two exceptionally promising athletes, seemingly bound for track and field stardom, when their careers were derailed by a condition that doctors and researchers say they are only now beginning to understand. Their experiences highlight the damaging expectations that can surround athletes, blurring the thin line between the discipline that allows athletes to achieve superhuman feats and the disordered patterns of behavior that can harm their health, as they push themselves, and are pushed by their coaches and trainers.   Mary Cain was the youngest ever US track and field athlete to make the World Championships team, a teenage phenomenon who held several national age-group records in middle-distance running. Pippa Woolven was one of the UK’s best steeplechase athletes, winning British university championships, competing in the 2012 World Junior Championships and earning an athletic scholarship to Florida State University. Then, as both women edged closer to the pinnacle of athletics, they developed Relative Energy Deficiency in Sport (REDs). The syndrome occurs when someone of any gender has overtrained and/or undereaten for a prolonged period in an attempt to improve their athletic performance, often without knowing the dangers of failing to compensate for the energy they expend in training, racing and their daily lives.