The Effect of Cycle Phase on the Adolescent Swimmers

In brief: Performance times of six postmen-archeal adolescents who competed on junior and senior national levels were recorded during a 12-week period. The fastest times for the 100-yd freestyle and 100-yd best event occurred during the menstrual phase and the slowest times during the premenstruum. Symptoms were rated biweekly with the Moos Menstrual Distress Questionnaire. Subjects reported feeling better during menstruation than premenstruation, and none reported dysmenorrhea. Based on basal body temperature, five of ten cycles were clearly biphasic, two were monophasic, and three were possibly biphasic with very short luteal phases. These results, albeit from a small sample, suggest that menstrual cycle phase may affect athletic performance as measured by practice times.