Continuous moderate intensity versus discontinuous high intensity treadmill running on anterior cruciate ligament laxity and hamstrings flexibility in eumenorrheic women.

OBJECTIVE: To differentiate running intensity and menstrual phase effects on knee stability before and after exercise.
METHODS: Ten eumenorrheic aerobically trained females were recruited to determine effects of a randomized crossover design of exercise intensity (85%HRR vs 42.5%HRR) on anterior cruciate ligament laxity (APLAX) and hamstrings flexibility (HF). A KT-2000 arthrometer measured APLAX and a 90-90 supine knee extension (MKE) and sit-and-reach test (SRD) measured HF in follicular (FP) and luteal (LP) menstrual cycle phases.
RESULTS: Significant difference pre-exercise was observed for both 90N and 120N APLAX in LP compared to FP. Exercise increased APLAX at 90N and 120N in both FP and LP with LP exhibiting larger changes than FP. MKE and SRD increased significantly following exercise but were not different across menstrual phases or between exercise intensities.
CONCLUSION: APLAX taken together with increased HF post-exercise demonstrates a less stable knee joint in the LP before and following exercise. © JCCA 2020.