Abstract
Context:. The prevalence of anterior cruciate ligament (ACL) injuries in female athletes appears to be highest during the late luteal and early follicular phases of the menstrual cycle. There may also be a relationship between decrements in proprioception and the prevalence of ACL injuries. Objective: The primary purpose of this study was to assess joint kinesthesia, joint position sense, and dynamic balance between the phases of the menstrual cycle. Design: Longitudinal. Setting: University Athletic Training Facility. Participants: Nine moderate to highly active females. Intervention: Subjects made nine visits to the research facility over a two month period. During these visits, balance, joint kinesthesia, and knee joint position sense were assessed over two consecutive menstrual cycles during the early follicular (Days 2-4), ovulatory (24-48 hours after LH surge detection), and mid-luteal (7 days after ovulation) phases. Joint position sense was tested using starting angles of 90 degrees when moving into extension and 0 degrees when moving into flexion. Target angles were 30, 50, and 70 degrees moving into flexion, and 20, 40, and 60 degrees moving into extension. Joint kinesthesia was tested moving into flexion and extension at both 15 and 45 degrees. Main Outcome Measures: Joint position sense error, the threshold to detect passive movement (kinesthesia), and the dynamic motion analysis (DMA) scores produced during a dynamic stability test. Results: No significant differences were found between the menstrual cycle phases and the threshold to detect motion, joint reposition sense error, or dynamic motion analysis. Conclusion: The menstrual cycle does not affect joint kinesthesia, joint position sense, or dynamic balance in moderate to highly active females.