title: Relationship of the menstrual cycle phase to anterior cruciate ligament injuries in teenaged female athletes.
abstract: BACKGROUND
  Anterior cruciate ligament (ACL) injuries are more common among female athletes compared to male athletes. Several studies have been reported to explain the gender difference in ACL injury rates and several risk factors underlying gender disparity are believed to exist. Hormonal effects are considered to be one of the etiological factors for female non-contact ACL injuries. The objectives of this study were to determine if ACL injuries occurred randomly or correlated with a specific phase of the female menstrual cycle in teenaged female athletes and then to determine if pre-menstrual and menstrual dysfunctions influenced these ACL injuries.
  
  
  METHODS
  Eighteen of 37 consecutive female athletes, with ACL injuries, met the study criteria: teenage, with regular menstrual cycle, and non-contact injury. The menstrual history, athletic activity, and injury history were collected.
  
  
  RESULTS
  Seventy-two percent of the subjects had premenstrual symptoms and 83% had menstrual symptoms. The subjective activity level at the follicular phase was significantly lowest between the phases. A significant statistical association was found between the phase of the menstrual cycle and ACL injuries (P = 0.0002). There were more injuries in the ovulatory phase than expected, and fewer injuries occurred in the other phases.
  
  
  CONCLUSIONS
  The results showed a significant increase in non-contact ACL injuries in teenage female athletes during the ovulatory phase of the menstrual cycle and the subjective activity level and the premenstrual and menstrual symptoms might not affect the likelihood of the injuries. These findings suggest that sex hormones might play a role in the incidence of female non-contact ACL injuries.
authors.affiliation: Department of Fundamental Nursing, School of Health Sciences, Faculty of Medicine, Tottori University, Yonago, Japan.
authors.forename: Noriko
authors.initials: N
authors.lastname: Adachi
authors.forename: Koji
authors.initials: K
authors.lastname: Nawata
authors.forename: Michio
authors.initials: M
authors.lastname: Maeta
authors.forename: Youichi
authors.initials: Y
authors.lastname: Kurozawa
mesh_terms: D000293:Adolescent; D000070598:Anterior Cruciate Ligament Injuries; D001265:Athletic Injuries / Q000503:physiopathology*; D002648:Child; D005260:Female; D005498:Follicular Phase; D006801:Humans; D008183:Luteal Phase; D008597:Menstrual Cycle; D010060:Ovulation