Crossing the midline? A beginner’s guide to what and why…
By the age of 3 or 4 years old, a Child should have mastered the bilateral skill known as “crossing the midline” – which means using both sides of the body together. This is the ability to move one hand, foot, or eye into the space of the other hand, foot or eye. We cross the midline when we scratch an elbow, cross our ankles, and read left to right.
Crossing the midline of your body helps build pathways in the brain and is an important prerequisite skill required for the appropriate development of various motor and cognitive skills. Children who have difficulty crossing the body’s midline often have trouble with skills such as reading, writing, completing self care skills and participating in sports & physical activities. These skills require a type of coordination that comes from experience with “cross-lateral motion,” which is movement involving the left arm and right leg, or the right arm and left leg at the same time.
Establishing a “worker hand” and a “helper hand” is a sign that the brain is maturing and lateralization is occurring, and is strongly correlated with the ability to cross the midline. Both sides of the brain need to talk to each other for the “worker hand” and the “helper hand” to work together and complement each other. Coordinating both sides of the body can be difficult for the Child who avoids crossing the midline. Often, these Children have not yet established a hand preference, sometimes using their left and sometimes using their right to draw, colour, write, eat, and throw.
Furthermore, when a Child has difficulty crossing the midline, it can affect his/her ability to read. While the Child is moving his/her eyes from left to right across the page, the eyes will stop at the midline to blink and refocus; however, when this happens, the Child will very frequently lose his/her place on the line and become confused as to where they left off. It also affects handwriting, as diagonal lines cross the midline, and the Child may need to stop in the middle of the page to switch hands when writing from left to right. Many self care and daily living skills require crossing the midline. For example, perfecting the skill of putting socks or shoes on requires one hand to cross over to the other side of the body.
Children who have difficulty crossing the midline may appear ambidextrous because they are often observed using both hands, but they actually have a hidden neuroprocessing issue. Both sides of their brains are not communicating, resulting in decreased coordination, decreased motor control of movements and difficulties achieving higher level skills. These Children can end up with two unskilled hands.
So, that is why some of the ‘groovy moves’ that are integrated into Phonics Stars™ Disco Dough Gym and the SHIMMI are there to help all the Children to further develop their ability to cross the midline, whether they are in the early stages or already well-developed. As outlined in this piece, the ability to have mastered this skill is essential to a great transition in to School and the ability to progress alongside the most able Children during Key Stage One. If you’d like to try some additional activities at home, here is a useful resource.