Crossing the midline

Being able to coordinate body sides and cross the midline is so important for your child’s development, says Liz Senior, occupational therapist and founder of Clamber Club

Why body coordination is so important

Cl i mb ing stairs, cutting with scissors and playing a musical instrument are all skills that children must learn, which all require body coordination. The ability to coordinate both sides of the body is an indication that both sides of the brain are sharing information with each other, which is vital to your child’s development. Body coordination forms the foundation for reading, writing, motor planning, gross and fine motor skills.

WHAT IS CROSSING THE MIDLINE?

Crossing the midline is a skill that is integrally related to body coordination. It refers to a child’s ability to move from one side over to the other side of the body (so, from left to right, for instance) to complete a task. The body has three midlines: the vertical midline (an imaginary line down the centre of the body), the horizontal midline (divides top and bottom halves of the body), and the front/back midline. The vertical midline is usually the one we mean when we refer to midline crossing.

“Midline crossing can be described as the ability to use either hand across the vertical midline of the body. For example, using the right hand to reach across and retrieve a fork placed on the left side of the plate,” explains Liz Senior, an occupational therapist and founder of Clamber Club.

“Many gross and fine motor skills depend on coordination of the two body sides,” she says. “Midline crossing also plays an important role in establishing hand dominance, forms the foundation for writing with pencils and cutting with scissors, and is needed for smooth eye movements when reading and writing, as well as on the sports field.”

HOW DOES IT DEVELOP?

The ability to reach across the midline and pick up an object normally occurs in

babies between eight and 12 months. As a baby enters his second year, the imaginary “wall” dividing right and left begins to crumble, the cooperation of the left and right brain improves and new movements become possible as the two sides of the brain work together.

By the end of the second year, the two sides of the body are able to complete different actions simultaneously – such as opening a jar by holding it with one hand while the other unscrews it.

As even more cooperation between the left and right brain develops at the beginning of the third year, the child can start to coordinate all four limbs. Activities such as jumping and clapping at the same time, or riding a tricycle, then enter the realms of possibility for a child.

WHAT IF MY CHILD DOESN’T CROSS HIS OR HER MIDLINE?

Parents and caregivers should be concerned if a child cannot cross his midline by the age of four. Retaining a midline problem into primary school can interfere with a child’s everyday classroom and physical education activities.

“Effective movement performance on any level requires a supportive relationship between the two sides of the body,” says Liz. “If a child does not cross his midline, and you find that it is affecting his ability to function effectively in the classroom, consult an occupational therapist.”

BODY AWARENESS Body awareness is another important skill which must be mastered in the development of bilateral body coordination. Body awareness refers to the ability to situate your body in a space without necessarily using your eyes – for example, knowing how high to lift your leg when climbing stairs without having to look at each individual one.

“Children who haven’t developed significant body awareness may be cautious with their movements and appear a bit clumsy,” says Liz. “They can also experience difficulty coordinating both sides of their body to complete bilateral tasks such as putting on shoes and socks and catching a ball.”