Why is crossing the midline so important?

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This article will help you to find out why crossing the midline is so important, and then you can try some easy activities to help your child! These fun activities are easy to do at home and come with lots of photos to show you just what to do!

crossing the midline spontaneously



Crossing the midline means that one hand spontaneously moves over to the other side of the body to work there.

Before this ability is established, you may have noticed that your young child tends to use the left hand on the left side of the body and the right hand on the right side of the body.

Why is midline crossing so important?

When your child spontaneously crosses the midline with the dominant hand, then the dominant hand is going to get the practice that it needs to develop good fine motor skills.

If your child avoids crossing the midline, then both hands will tend to get equal practice at developing skills, and your child’s true handedness may be apparently delayed.

So, in order for your child to do well at learning to write, there has to be a dominant, strong hand that becomes specialised at doing the job of controlling the pencil.

If both hands are being used, then your child may well end up with 2 mediocre hands rather than one strong, specialised hand. And mediocre hands do not produce great handwriting!

Some children with poor midline crossing skills go to school having developed a dominant hand, but have some discreet – or not! - “compensatory mechanisms” that make writing really awkward for them.
avoids crossing the midline


This girl has turned the paper sideways so she can write from bottom to top, instead of reaching over to her left side with her right hand to write from left to right.



crossing the midline avoidance






And this boy has shifted his body way over to the left, so his right hand does not have to reach over to work on his left side!

How does crossing the midline develop?

Midline crossing emerges as your child develops bilateral coordination skills. As your child learns to coordinate a strong hand which is doing something skilled (eg cutting) and an assistant hand which is helping (eg holding the paper), the ability to spontaneously cross the midline develops. Find out more about this process of developing handedness and see how midline crossing fits into your child’s development.

However, there is another vital factor in crossing the midline, and that is trunk rotation. If your child tends to have poor core stability, or holds him or her self “stiffly”, moving the body as a unit, then this may affect crossing the midline.
throwing a ball across the midline

Look at this picture of a girl throwing a ball to a target with her dominant hand. The child’s upper body has turned around (rotated), while the lower body (hips and legs) remains facing forward. There is some trunk rotation and the child is crossing the midline with the dominant hand.

poor trunk rotation means no midline crossing



Now look at this picture. The child has turned the lower body WITH the upper body, so the shoulders and the hips have both turned. There is no trunk rotation, and no midline crossing!

So, if there is poor core stability and a lack of good trunk rotation, then midline crossing will be affected.

What can I do to help my child develop midline crossing skills?

  • As the child gets better at getting both hands to work together in a complementary way, the ability to cross the midline begins to emerge. So if your child’s bilateral coordination skills are poor, then do some fun bilateral coordination activities at home.

  • Incorporate some of these midline crossing activities into your daily life!

  • And if your child needs to work on core stability and trunk rotation, try these simple core exercises for kids.

If you are concerned about your child’s handedness, then read this article about hand dominance to find out more.

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bilateral coordination activities for kids