Is W sitting bad for my child ?
Yes – Sitting in the W position (shown in the diagram opposite) is likely to be harmful to a child. It is normal for some ‘twist’ to be present in the long bone of the thigh in children. This is called femoral anteversion and naturally unfurls as the child ages. This natural straightening of the leg can be impaired if the hip muscles are stretched excessively. Sitting in the W position involves rotating the thigh inwards, relative to the hip. [Definition – ‘internal rotation’ moves the leg into a pigeon toe orientation. The opposite ‘external rotation’ moves the feet into a duck position like Charlie Chaplain]. For your child to sit in the W position with their bottom on the ground requires around 50 degrees of internal rotation, which is far in excess of what is required to walk. By habitually sitting in this position, the muscles that rotate the thigh inwards get shorter and the ones that rotate it outward get stretched – these are primarily in the buttock and inner thigh to the rear. In the stretched position, these muscles can’t control the leg movements as well as they should. As a rough ‘rule of thumb’ a child’s leg will position itself during walking halfway between how far it can rotate inwards and how far it can go outwards. With this in mind, you can see that a child who’s muscles are stretched to allow a lot of internal rotation will walk in a pigeon toed / knock kneed position. This is bad for a number of reasons:
Firstly, walking and running in this position is very inefficient. If you look at an Olympic standard runner, all of the body motions occur in a straight line to the front. The arms pump back and forwards, not across the body, the foot hits the ground and the knee passes over the top of the foot keeping the pelvis quite steady and facing straight ahead. Watching an in-toeing child run, you will note that the back foot flicks to the outside at it lifts off the ground. There is a lot of rotation occurring in the torso with the shoulders moving swiveling more than usual and the arms crossing the body as they swing.
Often there is a collapse of the pelvis toward the ground on one side as the other foot strikes the ground. This collapse occurs because of the poor angles and inefficient muscular control. A lot of muscular contraction is required to slow, stop and reverse this collapse and pull the pelvis back up ready to take the next step. All of this is very tiring – a child with poor leg position will use a lot more energy running 100m than a mechanically perfect child. It is also very inefficient as only the ‘straight ahead’ components of the motions (the forward vectors) will propel the body forwards. The torsional motions are wasted motions that serve only to pull the errant body parts back into a position where a next step is possible. It is not possible for the child to consciously ‘just straighten up’ without some external support.
There are also some psychosocial aspects to in-toeing. Perhaps a pigeon toed little girl with pigtails might be considered ‘cute’ but can cause embarrassment when it extends into adolescence and adulthood.