The Relationship between Serum Relaxin Concentrations and Knee Valgus

Abstract

Female athletes are at an elevated risk for tearing their anterior cruciate ligament, compared to their male counterparts. Though injury screening clinical tests and neuromuscular training programs have been widely implemented, injury rates remain high among female athletes. The purpose of this study was to examine the relationship between serum relaxin concentrations and knee valgus during three clinical tests (single leg squat, drop vertical jump, and single leg crossover dropdown). Twenty-two female athletes volunteered. Participants were scheduled for collection during the mid-luteal phase, when serum relaxin concentrations are known to be measurable. Blood samples were collected, and serum relaxin concentrations were quantified. Kinematic data were collected while participants performed the three clinical tests. Regression analyses revealed statistically significant relationships between serum relaxin concentrations and knee valgus throughout all tests. These findings suggest that serum relaxin concentrations and knee valgus are not independent of each other and more holistic approaches may be necessary to truly map out the risk for injury and ultimately reduce the rate of anterior cruciate ligament injuries. Thus, concluding that knee valgus, a highly utilized modifiable biomechanical risk factor, and relaxin, a hormone that has been associated with anterior cruciate ligament injury in female athletes, are related to each other.

The effects of sex hormones during the menstrual cycle on knee kinematics

“…The contradiction is mainly reflected in whether kinematics parameters are different in different phases. At present, the corresponding investigation mainly focuses on testing high-risk actions for non-contact ACL injury (e.g., cutting, landing, jumping, and so on) ( Chaudhari et al, 2007 ; Dedrick et al, 2008 ; Park et al, 2009a ; Park et al, 2009b ; Shultz et al, 2011 ; Shultz et al, 2012 ; Okazaki et al, 2017 ; Gilmer et al, 2020 ; Gilmer and Oliver, 2020 ).…”

“…In studies of jumping, cutting, stopping, and other actions, the conclusions were that knee kinematics parameters were not different in different phases. However, the above studies did not exclude anovulatory and LPD ( Park et al, 2009a ; Park et al, 2009b ; Shultz et al, 2012 ; Okazaki et al, 2017 ; Gilmer et al, 2020 ; Gilmer et al, 2020 ). Therefore, using a standardized menstrual cycle methodology is a prerequisite for conducting such a study in the future ( Hewett et al, 2007 ; Balachandar et al, 2017 ; Somerson et al, 2019 ).…”