Menstrual cycle stage and oral contraceptive effects on anterior tibial displacement in collegiate female athletes
Hicks-Little, C.A.; Thatcher, J.R.; Hauth, J.M.; Goldfuss, A.J.; Cordova, M.L.
Journal of Sports Medicine and Physical Fitness 47(2): 255-260
2007
ISSN/ISBN: 0022-4707 PMID: 17557069 Document Number: 611198
The aim of this study was to establish if differences in anterior tibial displacement exists in collegiate female student-athletes at different stages of the menstrual cycle. a 2 x 3 factorial design with repeated measures on the second factor guided this study. The first independent variable was group with 2 levels (control and oral contraceptive) and the second independent variable was menstrual cycle phase with 3 levels (follicular, ovulation, luteal). The single dependent variable was anterior tibial displacement. All data were collected in a research laboratory. 53 female student athletes (control: n=28; oral contraceptive: n=25) with no previous history of knee injury or anomalies with a normal 28-30 day menstrual cycle participated. anterior tibial displacement (mm) measurements were taken on days 1 (follicular phase), 13 (ovulation phase), and 23 (luteal phase) of each subject's menstrual cycle using a KT1000 knee arthrometer. For the entire group, statistically significant increases in anterior tibial laxity were found (F=4.49; df=52.1; P<0.05) between the follicular cycle (0+/-SD =5.14 mm) and ovulation cycle (0+/-SD=5.81 mm); and follicular cycle (0+/-SD=5.14 mm) and luteal cycle (0+/-SD=5.79 mm). A separate analysis of the non-birth control group revealed no significant difference in anterior tibial laxity throughout the stages of the menstrual cycle. The results of this study suggest that: 1) the menstrual cycle does have an influence on laxity of the anterior displacement of the knee; 2) significant increases in anterior displacement are shown during the ovulation and luteal phases of the menstrual cycle; and 3) birth control subjects tend to have increased laxity when compared to those subjects who are not on hormone therapy.