Do your kids, same as many others, have a habit of sitting in the W position like shown in the picture below?
If that is so, you need to immediately start teaching them to never sit in that position again. The reason is that this position may cause their hip rotation points to ged damaged or destroyed and therefore lead to serious orthopedic problems later on in life.
How to prevent W-sitting.
The most effective (and easiest) way to prevent a problem with W-sitting is to prevent it from becoming a habit it the first place. Anticipate and catch it before the child even learns to W-sit. Children should be placed and taught to assume alternative sitting positions. If a child discovers W-sitting anyway, help him to move to another sitting position, or say, “Fix your legs.” It’s very important to be as consistent as possible.