Well honestly, it's perhaps not a good advert for the class I am promoting. The picture is just a stock image you can buy over the Internet so apologies to the woman in the picture (if you should ever read this article and if you suffer knee pain I will very happily help you out).
The exercise she is doing is one that we do in the 'Knee, Hip & Balance Class'however if you are one of the class participants you would soon be given some coaching to correct the leg alignment. From this picture alone I know that when this lady walks she doesn't walk properly but instead uses her lower back muscles to hitch her hip up and then swings her leg around the outside of her body-line. If (and that is a big 'if')she doesn't currently have knee pain she has very likely had knee or hip pain previously and will again in the future.
The faulty movement patterns described can be fairly easily resolved with regular practice of a number of exercises whilst focusing on a few key points. This also applies to many other knee and hip problems which would generally demonstrate different imbalances on the exercise shown in the picture.
Participation in my Knee, Hip and Balance Class will teach you the skills you need, with the supervision you need to point out the weaknesses and imbalances you demonstrate and how to correct them.
If you wish to gain a better understanding of the basic principles then you can read the following two articles.