title: Tibial acceleration profiles during the menstrual cycle in female athletes.
abstract: OBJECTIVE
  Fluctuating levels of endogenous estrogen are thought to have an adverse effect on lower limb biomechanics, given the observed higher rate of ACL injury at certain phases of the menstrual cycle. The purpose of this study was to investigate the effects of fluctuating endogenous estrogen levels during the menstrual cycle on acceleration transients at the proximal tibia in young physically active females.
  
  
  METHODS
  Eleven females aged 16-18 years participated in this study and were compared to a male control group. Female subjects were tested at each of the four phases of the menstrual cycle: menses, follicular, ovulation and luteal. On each test occasion, acceleration transients at the proximal tibia were measured while subjects performed an abrupt deceleration task (simulated netball landing).
  
  
  RESULTS
  No significant differences were found between the different phases of the menstrual cycle for peak tibial acceleration (PTA; P = 0.57), and time to zero tibial acceleration (TZTA; P = 0.59). However, there was a significant difference for time to peak tibial acceleration (TPTA) between menstruation and follicular (P = 0.04), menstruation and ovulation (P = 0.001), menstruation and luteal phase (P = 0.002), and follicular phase and ovulation (P = 0.007). In the male control group, no significant between-test session differences were observed for PTA (P = 0.48), TZTA (P = 0.08) and TPTA (P = 0.29). While there were no significant between-group differences for PTA (P = 0.21) and TZTA (P = 0.48), significant between-group differences were observed for TPTA (P = 0.001).
  
  
  CONCLUSIONS
  The results of this project strongly suggest that serum estrogen fluctuations have an effect on tibial acceleration profiles in young female athletes during different phases of the menstrual cycle.
authors.affiliation: Musculoskeletal Research Unit, Central Queensland University, PO Box 4045, Rockhampton, QLD, 4700, Australia. ehohmann@optusnet.com.au.
authors.forename: Erik
authors.initials: E
authors.lastname: Hohmann
authors.affiliation: Centre for Health, Exercise and Sports Medicine Physiotherapy, Melbourne School of Health Sciences, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Parkville, VIC, 3010, Australia. albryant@unimelb.edu.au.
authors.forename: Adam L
authors.initials: AL
authors.lastname: Bryant
authors.affiliation: Musculoskeletal Research Unit, Central Queensland University, PO Box 4045, Rockhampton, QLD, 4700, Australia. eli_e@gmx.net.
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Livingstone
authors.affiliation: School of Medical and Applied Sciences, Central Queensland University, Bruce Highway, Rockhampton, QLD, 4702, Australia. p.reaburn@cqu.edu.au.
authors.forename: Peter
authors.initials: P
authors.lastname: Reaburn
authors.affiliation: Department of Orthopaedic Surgery, Royal Brisbane Hospital, Herston, Australia. kevin_tetsworth@health.qld.gov.au.|Division of Surgery, University of Queensland Medical School, Herston, QLD, 4029, Australia. kevin_tetsworth@health.qld.gov.au.
authors.forename: Kevin
authors.initials: K
authors.lastname: Tetsworth
authors.affiliation: Department of Orthopaedic Sportsmedicine, University of Technology, Ismaninger Strasse 69, 81675, Munich, Germany. a.imhoff@lrz.tu-muenchen.de.
authors.forename: Andreas
authors.initials: A
authors.lastname: Imhoff
mesh_terms: D000293:Adolescent; D000070598:Anterior Cruciate Ligament Injuries; D056352:Athletes; D005260:Female; D006801:Humans; D007718:Knee Injuries / Q000209:etiology* / Q000503:physiopathology; D008597:Menstrual Cycle; D013177:Sports / Q000502:physiology*; D013977:Tibia / Q000502:physiology*
keywords: Anterior cruciate ligament injuries; Female athletes; Menstrual cycle; Tibial acceleration profiles