“You are seeing big differences in right and left legs,” Decker said. “What we are finding is the non-dominant leg has been injured, especially the ACL, much more than the dominant. Females have two times the rate as males of the non-dominant leg.”
Look at the image above left which shows a woman with good postural alignment and balanced leg strength. You can see that both her feet point straight ahead as do her knees and her hips and shoulders are level. This means when she repeatedly squats while skiing, her ankles, knees, and hips will work together as a team distributing workload throughout all the lower body muscles and avoiding excessive strain on any ligaments, cartilage, or other connective tissues in her body. This means she is very unlikely to tear her ACL while skiing.
Now look at the image above on the right. Notice how her feet turn out at different angles. Her knees also point in different directions and her hips and shoulders are not level. Since we know that how we stand is how we move and bad posture equals bad form, there is no way her body will move or ski in a balanced and even way. She will end up overloading her dominate side while collapsing on her non-dominate side. This is a recipe for injury including an ACL tear - whether it happens while she's alpine skiing, playing soccer, returning a tennis serve, or jumping up and down during a bootcamp workout.
Here we see the same woman from above right walking down a flight of stairs. Notice how her right knee is collapsing inward (valgus knee stress, internal femur rotation, foot abduction) and her upper body is offsetting to the right as compensation. The same thing will happen as she skies downhill making turn after turn. As her muscles fatigue they will allow even more collapsing and twisting of her right leg possibly leading to a torn ACL.
I would be happy to offer anyone who is seriously interested in correcting their imbalances to prevent injury a free posture evaluation and consultation. I would also offer the same to anyone who has suffered a torn ACL or other skiing injury and would like help getting back to 100%.