gms | German Medical Science

54. Jahrestagung der Norddeutschen Orthopädenvereinigung e. V.

Norddeutsche Orthopädenvereinigung

16.06. bis 18.06.2005, Hamburg

What is the association between the menstrual cycle and ACL laxity and muscular stiffness in adolescent athletes?

Meeting Abstract

  • corresponding author E. Eiling - Klinik für Orthopädie, Universitätsklinikum Schleswig-Holstein, Campus Kiel, Kiel
  • A. Bryant - Rockhampton
  • A. Murphy - Sydney
  • W. Petersen - Münster
  • E. Hohmann - Rockhampton

Norddeutsche Orthopädenvereinigung. 54. Jahrestagung der Norddeutschen Orthopädenvereinigung e.V.. Hamburg, 16.-18.06.2005. Düsseldorf, Köln: German Medical Science; 2005. Doc05novP03

The electronic version of this article is the complete one and can be found online at:

Published: June 13, 2005

© 2005 Eiling et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License ( You are free: to Share – to copy, distribute and transmit the work, provided the original author and source are credited.




The high risk of anterior cruciate ligament (ACL) injuries in female athletes may be related to hormonal fluctuations resulting in an increased laxity of ligaments and muscles. This study examined changes in lower limb musculotendinous stiffness (MTS) and knee laxity over the course of the menstrual cycle.


Ten female netball players (16-18 years) who were not using hormonal contraceptives participated in this study. Test sessions took place at menses, mid follicular phase, ovulation and mid luteal phase. ACL laxity was determined at each test session using a KT-2000® knee arthrometer. MTS was assessed prior to, and following a standardised warm-up.


Repeated measures ANOVA revealed significant (p<0.05) main effects of test-session and warm-up on MTS. MTS was found to significantly decrease by 4.2 % following the warm-up intervention. MTS was significantly lower at week 3 (ovulatory phase) in contrast to week's 1 and 2 (8.7 % and 4.5 %, respectively). For knee laxity measures, repeated measures ANOVA revealed no significant (p<0.05) differences across the menstrual-cycle.


A reduction in MTS results in greater reliance on reflexive response from the contractile components of the muscle due to a decreased contribution from passive elastic structures. A reduction in MTS will also increase electromechanical delay (EMD). Given that extreme loads are applied to the knee joint within milliseconds, the contractile components cannot respond quickly enough to counteract these sudden and potentially damaging forces. Lower MTS is proposed to be a contributing factor for the higher incidence of ACL injury at ovulation.