Adolescents' sleep and next day effort was studied in 18 female competitive adolescent athletes. A subjective assessment of the previous night's sleep, their perception of the difficulty of the choices offered and the difficulty of tasks selected was completed before routine lessons. Sleep amount was related to the perception of the difficulty of the task, while awakenings were related to an avoidance of the least preferred maneuvers. Individuals who experienced the greatest number of awakenings and most time awake at night were more likely to select the least difficult of these tasks. Sleep disturbance in adolescence may magnify the challenges they experience and cause them to underestimate their ability to meet those challenges.