Get in (Mid)Line

There are two sides to every story. The same applies to the human body.

Practically any movement we do, big or small, requires the left and right side to work together to stabilize and/or execute a motion. Even reading this post relies on such teamwork. Bilateral coordination (also known as bilateral integration) is the ability to simultaneously use both sides of the body. Like all developmental skills, this ability is gained through our own body awareness, experiences, and practice.

Learn as they Go

Bilateral coordination develops as babies learn to move their torso and limbs. As they’re placed in various positions (like their side, tummy, and back), they discover different ways move their bodies. This exploratory movement not only provides awareness of what their body parts can do, but also builds muscle strength and coordination.

As your little one grows, their coordinated movements become more refined and efficient. The stages of bilateral coordinated movement are:

  • Symmetrical Bilateral Coordination. This is when the movements of both sides of the body are like a mirror-image of one another. Think of when your baby putting both hands to their face at the same time during peek-a-boo or clapping their hands together. Later, they’ll use this skill for jumping with both feet.

  • Reciprocal Bilateral Coordination. One side of the body does the exact opposite movement of the other side of the body, following a rhythm. You’ll see this with crawling, walking, and eventually, peddling a bike.

  • Asymmetrical Bilateral Coordination. When each side of the body learns to perform a different and separate task to accomplish an activity. The dominant hand will complete the main task while the non-dominant hand stabilizes the action. Most of our daily activities rely on this particular form of coordination. This is seen when your child is cutting paper with scissors, using utensils when eating, or tying their shoes.

  • Crossing Midline. Your midline refers to the where the two sides of your body meet. Your nose, tongue, mouth, and belly button are all at your midline. Your baby rolling over from their back to belly or reaching for a toy that’s slightly off to one side are examples of crossing midline. As their movements mature, they’ll cross midline spontaneously when completing actions like brushing teeth, combing hair, or even when reading and writing. Additionally, midline crossing promotes laterality (hand dominance).

Like motor planning, bilateral coordination takes body awareness and practice. The more your child engages with their environment, the more refined their movements will be. With that said, here’s some variables that affect coordination:

  • Too much time in baby positioners and seats
  • Too much passive screen time
  • Limited interaction with their surroundings
  • Limited opportunities to move both sides of their body, rotate their trunk, or cross midline
  • Presence of primitive reflexes

Clumsy and Uncoordinated

Children who have trouble executing bilateral coordinated movements face many challenges completing activities. They may:

  • Have difficulties completing smooth, rhythmic, and sequenced actions like cutting or folding paper
  • Have trouble copying or imitating the correct sequence of actions to complete a task like washing hands or shoe tying
  • Have poor oral-motor skills affecting speech, eating, and facial expressions
  • Have poor body awareness, impacting tasks where vision is obstructed or focused elsewhere, like putting on a pullover shirt or touch-typing
  • Have poor hand-eye coordination, resulting in illegible handwriting or trouble catching a ball
  • Not have a hand dominance
  • Have trouble with math and/or reading
  • Have difficulties sitting extensive periods of time

Here are some strategies for improving/building bilateral coordination:

  • Build up that body awareness. To coordinate movement, you must know where your extremities are and how they move. That means activating your child’s proprioceptive and vestibular systems. A quick way to do this is a trip to the playground. Don’t have that? Try doing basic PE warmups: modified jumping jacks, squat jumps, stretches and bends, toe-touches, lunges, etc.
  • Look Ma, both hands. Have your child help you around the house with chores that require using both hands. Have them carry groceries into the house or move their play furniture around so you can vacuum/sweep the floor. This engages the two sides of their body to communicate in an action and promotes muscle strength/stability needed for more refined tasks.

  • Rhythm and rhyme. Coordination has rhythm. Look at the many bilateral movements we do as examples: walking, clapping, even writing has a flow to it. You can work on rhythm by using alternating movements. You can have your child grab some wooden spoons and pretend to be Travis Barker by imitating a beat sequence (right-left, right-right-left). You can have them march in place while maintaining a steady pace for 1 minute with the help of a metronome (no speeding up or slowing down). For more of a challenge, put on a music video and try to learn the dance moves. This matches body movement with their favorite songs.

Bilateral Integration: Stages of Bilateral Integration for Reading, Tracking, Writing and Crossing the Midline – Integrated Learning Strategies (
All About Crossing The Midline (
Kranowitz, C. (2003). The Out-of-Sync Child Has Fun: Activities for Kids with Sensory Processing Disorder.  New York, NY: A Perigee Book.
Bodison, S.C. (2010). The Sensory Integration and Praxis Tests Illuminating Struggles and Strengths in Participation at School.


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