Bilateral Coordination and Crossing Midline

What is bilateral coordination?

Bilateral means “both sides” Bilateral coordination refers to the ability to coordinate both sides of the body at the same time in a controlled and organized manner. Simply put, bilateral coordination is using both sides of the body together in an activity; for example, stabilizing paper with one hand while writing or cutting with the other.

Bilateral coordination development includes three stages: symmetrical, alternating, and use of a dominant side together with a stabilizing side. Bilateral coordination develops sequentially; meaning that first, your child should master symmetrical coordination, then alternating coordination, followed by a coordination of a dominant hand and supporting hand (once hand dominance is established). Examples of symmetrical bilateral coordination include: pulling socks or pants up your leg/foot, squeezing a bottle of paint at the midline, jumping jacks, catching a ball with two hands, and using a rolling pin.

Examples of alternating bilateral coordination include: climbing, hopscotch, riding a bike, swimming and animal walks. Examples of using a dominant side and stabilizing side together include: cutting with scissors while stabilizing the paper on the other hand, writing and coloring, manipulating fasteners (tying shoes, buttoning, etc.), opening containers, and cutting food with a fork and knife.

Why is bilateral coordination important?

Being able to coordinate both side of the body together to complete an activity is an integral part of completing everyday tasks. Most self-care, motor, and play activities require age-appropriate bilateral coordination skills. Children who have difficulty coordinating both sides of their body can have difficulty completing activities of daily living (getting dressed, tying shoes, etc.), fine motor activities (banging blocks together, stringing beads, buttoning, etc.), visual motor tasks (drawing, writing, cutting, catching/ throwing, etc.), and gross motor activities (crawling, walking, climbing stairs, riding a bike, etc.). A child who lacks adequate bilateral coordination skills, may struggle to complete daily activities, such as the ones listed above.

How can I help my child improve bilateral coordination skills at home?

If you suspect your child has difficulties with bilateral coordination, always bring this up with your child’s OT! Chances are, your child’s OT is already incorporating bilateral coordination activities into their weekly treatment sessions. Additionally, there are tons of easy, accessible, and fun ways to incorporate bilateral coordination activities into your child’s play to improve these skills.

Some examples of bilateral coordination activities to complete at home include:

Cooking play/exploration (i.e. frosting cookies with a butter knife, spreading peanut
butter/jelly on toast, pouring water, opening/closing jars, mixing batter, etc.)

Tearing/crumbling tissue paper, cotton balls, etc. to create a craft Stringing large blocks, small beads, uncooked pasta, etc. onto pipe cleaner, yarn, string

Snipping/cutting with scissors Stencils, drawing, coloring, or painting on a vertical surface (secure paper with one hand and draw with opposing hand) Folding paper airplanes

    Lacing activities (i.e. use a hold punch to create holes and have child lace string or yarn through holes)
 Popping bubbles with both hands
 Connecting/separating Legos, magnetic blocks, pop-beads, mega blocks, etc.
 Pulling apart Play-Doh to find hidden objects; using Play-Doh tools
 Playing with Mr. Potato Head
 Tape a “track” onto a wall and push a ball or large car (holding with both hands) along the track
 Catching/throwing with both hands
 Rock climbing, ascending/descending stairs
 Animal walks

What is crossing midline?

Crossing midline is an important skill related to bilateral coordination. When OTs and other
professionals talk about “crossing midline”, the midline they are referring to is an imaginary line
drawn from the head to the feet that separates the left and the right halves of the body. Crossing
midline refers to the ability to spontaneously cross over the midline of the body during motor or
functional tasks, moving one hand, foot, or eye into the space of the other hand, foot, or eye (i.e.
sitting with legs crossed, scratching the opposite elbow, successfully intersecting lines to draw a
cross, reading left to right, etc.). 

Babies and toddlers may use both hands equally and pick up or interact with an object with whichever hand is closer (i.e. if the item is on the left side of the table they will likely use the left hand, and vise versa). Around 2 years of age, crossing midline can happen spontaneously; however, by 3-4 years of age a child should typically have refined the skill of crossing midline, with this skill improving through ages 4-9.

Why is crossing midline important?

Crossing the midline affects fine and gross motor development, as well as higher academic
skills such as reading. Crossing midline is vital to the development of using both sides of the
body together (bilateral coordination) during daily tasks, such as putting on shoes and socks,
writing and cutting. A child who avoids crossing midline may have difficulty establishing hand
dominance, and alternate hand use when coloring, writing, eating or throwing.

Additionally, crossing midline strengthens the neural connections between the left side of the brain (language and logic) and right side of the brain (emotions and creativity), allowing the whole brain to work
together. When the brain functions as a strong unit, the child can better use language (left brain) to express their feelings (right brain), leading to improved emotional regulation!

How can I help my child practice crossing midline at home?

 Washing tables or windows (encourage large arm movements and use of only one arm at a time)
 Erasing a large whiteboard or chalkboard
 Sitting back-to-back with a partner and passing a ball back and forth from the waist level
 Place stickers on one side of the body and have your child remove them with their opposite hand
 Draw figure-8 patterns on paper, in the air, in sand with hands or feet, etc.
 Playing games such as Twister or Simon Says
 Drawing a large rainbow on paper, with chalk on the ground, etc.
   (picture your child seated crisscross and drawing the large rainbow in front of them using only one hand)
 Windmill exercise


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