Female hormone cycle linked to knee laxity

Recently published research from the University of Calgary has identified a connection between the laxity of a woman’s knee joint and her monthly hormone cycle.

The research project, which was a collaborative effort among researchers in kinesiology, engineering and the health sciences, revealed that not all women experience knee laxity at the same time in their menstrual cycle. The investigators hypothesized that this is likely why scientists largely ignored an association between the hormone cycle and knee injury in previous studies, according to a University of Calgary press release.

In a series of recent papers published in the British Journal of Sports Medicine and The American Journal of Sports Medicine, the researchers reported that while 14 of 26 subjects exhibited the greatest amount of knee laxity during the ovulation phase, 10 others demonstrated the greatest laxity during the follicular phase and 2 subjects experienced it during the luteal phase.

“What this shows us is that the connection between the hormonal cycle and knee laxity is not a cookie-cutter relationship,” co-lead author and kinesiology professor Darren Stefanyshyn, PhD, said in the press release. “Individuals have significant differences, and I think that finding out why these differences occur could go a long way toward helping athletes understand if they are more at risk and perhaps [design] interventions to help prevent injury.”

In the University of Calgary study, 26 women were monitored throughout the course of their monthly cycle. Their knee laxity was measured at each phase and they were asked to perform several athletic movements like quick cuts or sharp jumps.

The researchers found that greater knee laxity led to biomechanical differences that could lead to injury in a game situation, according to the press release.

Female athletes are between two and eight times more likely to injure their ACL knee ligaments than men, the researchers noted.