The stations started at the foot/ankle complex and we are working our way up the chain. The knees are the next stop and they are a popular area when it comes to skiing/riding and even more popular (unfortunately) when it comes to aches and pains.
The knee joint is classified as a hinge joint. By definition, a hinge will swing open and closed...much like a door that only moves along one plane and on it's axis. However, in function, the knee is capable of much more - being involved in motions that require the knee to move in the other two planes (frontal and trasverse), sideways and rotations. These other (and dare I say more important) motions can be illustrated by standing up and rolling the arches of your feet up and down to the floor. "Looking down the barrel" you will note that your shin bones are twisting and this motion is carried further up the leg all the way up to your thigh bones causing your butt muscles to start firing up. This vital motion is referred to as pronation and supination. In the past, these terms have been applied to just the foot/ankle complex. According to Gary Gray, every joint in the body is capable of pronation/supination. In some ways it can be viewed as a more general way to look at how the human body goes through the loading/unloading of groups of muscles together to result in human movement.
All that being said, we are all familiar with the knee flexing and extending (bending and straightening). Sounds simple, but when other joints are not working properly (let's say the foot/ankle becomes restricted which is very common), then the knees will become more of a mobile joint instead of an area of stability. Now all the sudden the knees become less stable (wobbly knees) and over time this gets expressed as various "ouches."
Very often, with "cranky knees" we have found we have matching hips and feet/ankles that are working sub-par. As a result of restrictions in both the hips and feet/ankles, the knees have no choice but to become less stable to perform the tasks at hand by moving more.
On the slopes, your suspension is all thrown off! The inability to flex or absorb the terrain changes with your knees (especially you bump lovers), forces your body to use the next best thing which is usually less than optimal. So, if the knees are becoming more mobile due to a foot/ankle AND/OR hip complex that has become more stable (which is LESS mobile)... now I'm the guy who's knees are not too happy as I look down a field of moguls!
So, the take home message is - if you are the cranky knee guy or girl, you might have to look above and below the joint to see what is going on at your hips and at your feet/ankles.
Next on the list are the hips! We will talk about them a little later....