Start Date
23-4-2026 12:00 AM
Description
Female participation in sport continues to increase, yet women remain largely underrepresented in research. Due to hormonal differences, additional research is needed to understand how menstrual cycle (MC) phases influence performance and injury risk. Females experience higher incidences of anterior cruciate ligament (ACL) injuries, which may be influenced by hormonal fluctuations. The purpose of this study is to examine how MC phases and changes affect muscular strength and ligament laxity at the knee. Muscular strength and ligament laxity will be tested twice during the MC: once during the early follicular phase (EFP) and the second set are to be collected during the ovulatory phase (OP). Ligament laxity will be measured using arthrometer testing of the ACL at varying forces on both legs to calculate a compliance index. Muscular strength will be evaluated using maximal-effort knee extensions at two velocities using an isokinetic dynamometer to determine peak torque and hamstring-to-quadricep ratios. It is expected that muscular strength and ligament laxity will increase during the OP compared to the EFP. These findings may help identify periods of increased ACL injury risk phases in female athletes.
Research Highlights
The Problem: Female athletes are estimated to be 2 to 10 times more likely to sustain an anterior cruciate ligament (ACL) injury compared to male athletes, yet they remain underrepresented in research regarding how hormonal fluctuations influence injury risk.
The Method: This study utilizes an experimental, repeated-measures design involving 34 eumenorrheic collegiate female athletes to compare knee ligament laxity via a KT-2000 arthrometer and muscular strength via a Biodex System 4 isokinetic dynamometer across the early follicular and ovulatory phases.
Quantitative Finding: The study population consists of 34 athletes with regular menstrual cycles of 26 to 34 days; ligament laxity is measured using tibial displacement at forces of 67 N and 89 N; muscular strength is assessed at velocities of 60°/s and 180°/s.
Finding: Researchers hypothesize that peak estrogen levels during the ovulatory phase will increase both muscular strength and ligament laxity, while the hamstring-to-quadriceps (H:Q) ratio will remain unchanged.Recommended Citation
Johnson, Nicole Waldo, "Effects of Menstrual Cycle Phases on Muscular Strength and Ligament Laxity" (2026). 2026 Student Academic Showcase. 31.
https://digitalcommons.lindenwood.edu/src_2026/Posters/1/31
Included in
Effects of Menstrual Cycle Phases on Muscular Strength and Ligament Laxity
Female participation in sport continues to increase, yet women remain largely underrepresented in research. Due to hormonal differences, additional research is needed to understand how menstrual cycle (MC) phases influence performance and injury risk. Females experience higher incidences of anterior cruciate ligament (ACL) injuries, which may be influenced by hormonal fluctuations. The purpose of this study is to examine how MC phases and changes affect muscular strength and ligament laxity at the knee. Muscular strength and ligament laxity will be tested twice during the MC: once during the early follicular phase (EFP) and the second set are to be collected during the ovulatory phase (OP). Ligament laxity will be measured using arthrometer testing of the ACL at varying forces on both legs to calculate a compliance index. Muscular strength will be evaluated using maximal-effort knee extensions at two velocities using an isokinetic dynamometer to determine peak torque and hamstring-to-quadricep ratios. It is expected that muscular strength and ligament laxity will increase during the OP compared to the EFP. These findings may help identify periods of increased ACL injury risk phases in female athletes.