Introduction: Gender differences exist with regards to ligament and tendon injuries. Lower collagen synthesis has been observed in exercising females vs. males, and in users of oral contraceptives (OC) vs non-users, but it is unknown if OC will influence tendon biomechanics of females undergoing regular training. Material and Method: 30 female athletes (handball players, 18-30 yrs) were recruited: Fifteen long-term users of OC (7.0±0.6 yrs) and 15 non-users (> 5 yrs). Synchronized values of patellar tendon elongation (obtained by ultrasonography) and tendon force were sampled during ramped isometric knee extensor MVC to estimate mechanical tendon properties. Further, tendon cross-sectional area and length were measured from MRI images, and tendon biopsies were obtained for analysis of tendon fibril characteristics and collagen cross-linking. Results: Overall, no difference in tendon biomechanical properties, tendon fibril characteristics or collagen cross-linking was observed between the OC-users and non-users, or between the different phases of the menstrual cycle. In athletes, tendon CSA in the preferred jumping leg tended to be larger than the contra-lateral leg (p=0.09), and a greater absolute (p=0.01) and normalized tendon stiffness (p=0.02), as well as a lower strain (p=0.04) were observed in the jumping leg compared to the contra-lateral leg. Conclusion: The results indicate that long-term OC use or menstrual phases does not influence structure or mechanical properties of the patellar tendon in female team handball athletes.
Journal of Applied Physiology, 2013, Vol 114, Issue 8, p. 998-1008
Journal Article; Research Support, Non-U.S. Gov't; Adolescent; Adult; Analysis of Variance; Athletes; Biological Markers; Biomechanical Phenomena; Biopsy; Case-Control Studies; Collagen; Contraceptives, Oral; Cross-Sectional Studies; Exercise Test; Extracellular Matrix; Female; Humans; Isometric Contraction; Magnetic Resonance Imaging; Menstrual Cycle; Muscle, Skeletal; Patellar Ligament; Time Factors; Young Adult