The purpose of this study was to examine the growth pattern and sexual maturation rate of identical triplets, one of whom was a highly ranked competitive gymnast who subsequently retired from the sport 8 months into the study. Baseline measurements were conducted when the sisters were 11.5 years of age. They were then repeated 18 and 24 months later. The gymnast had been in training and competition for 5 years at the time of the initial measurements. At the time of baseline measurements on the three girls, the gymnast's height fell between that of her two sisters, but at the 18‐month measurement, which was 10 months after she retired, she had grown 10.2 cm, compared with 4.9 and 5.8 cm for her sisters. Likewise, during this same time frame, she gained 13.6 kg, while sister 1 gained 10.9 kg and sister 2 gained 5.9 kg. At baseline, the gymnast was at the 68th percentile of weight for age, and her sisters were at the 83rd and 95th percentiles, respectively. Eighteen months later, the gymnast had increased to the 83rd percentile, while sister 2 decreased to the 70th and sister 3 remained at the 95th. Furthermore, during this time, the body fat of the gymnast increased from 13.6 to 18%, and her waist to hip ratio decreased by 0.07, indicating an increase in fat deposition in the hip region. Onset of menarche occurred at 12 years, 10 months in the gymnast, and at 11 years, 3 months and 11 years 9 months in sisters 1 and2, respectively. Taken together, these data indicate that the gymnast may have undergone mild growth retardation during her years in training and competition, followed by catch‐up growth in the 10 months after she retired from the sport.