Testosterone May Strengthen ACL


New research by Romani et al. from The John Hopkins University in Baltimore has been published in The Knee and has shown that testosterone levels can have an impact on the strength of the anterior cruciate ligament (ACL). Romani’s previous research has shown that estrogen could reduce ACL strength.

The most recent study was performed on male rats. The ACLs of normal rats were compared to those of castrated rats. The testosterone levels in the castrated rats was close to zero. The researchers concluded that “rats with normal circulating testosterone had higher ACL load-to-failure and ultimate stress, indicating that testosterone may influence ACL strength and the injury rate of the ligament“. The results suggest that testosterone may help to strengthen the ACL. If coupled with the findings that estrogen could weaken the ACL, we can start to understand some of the reasons behind the differences in prevalence of ACL injuries between the sexes. Obviously, this only holds if these findings are the same in humans as well. It would also be interesting to know if these findings apply to other ligaments.

Skiing And Snowboarding Injuries

A study by Suezie Kim et al. published in The American Journal of Sports Medicine has shown that injury rates in snowboarders are slightly higher than injury rates in alpine skiers. Snowboarders more commonly injure their wrists, shoulders and ankles while skiers tend to injure their knees.

In skiers the knee accounts for a third of all injuries but female skiers are twice as likely to injure their knees as men and 3 times as likely to strain their anterior cruciate ligaments (ACL). Gerhard Ruedl et al. found that women “showed a 2-fold higher risk of suffering an ACL rupture of their non-dominant leg”. Men had an equal chance of injuring the right or left knee. Ruedl told Reuters Health that women showed greater discrepancies in strength and proprioception (sense of joint positioning)  between their dominant and non-dominant legs. Most female skiers injured their left (non-dominant) ACLs during right turns when the forces on the left (outside) leg were greatest.