What Is Crossing the Midline, and Why Do 3-to-5-Year-Olds Practice It?

Crossing the midline means reaching a hand, foot or eye across the middle of your body to the other side, like touching your right hand to your left knee. At Flow Academy BJJ Riverside, our Little Ninjas class for ages 3 to 5 turns it into games, Mondays and Wednesdays from 3:45 to 4:30 PM, at 10081 Indiana Ave, Suite A-1 once our new home opens in mid-November 2026.

The afternoons are getting shorter and more play moves indoors, which makes this a good time to notice something we watch for on the mat every week.

What the Midline Actually Is

Picture a line running from the top of your head down between your feet. Everything on one side is “left,” everything on the other side is “right.” Crossing the midline is any move that goes over that line: a right hand picking up a toy on the left, a left foot stepping toward the right, eyes following a ball from one side to the other.

What You Might Notice at Home

Plenty of kids this age grab with whichever hand is closest. A four-year-old reaching for a cup on her left side with her left hand, even when the right hand would be easier, isn’t doing anything wrong. Crossing over is a skill, and at this age skills come with play, not lectures. So we make it a game.

How We Turn It Into Play on the Mat

Our coaches run a bear crawl where the opposite hand and knee move together, so every step crosses the middle a little. They set out cones and ask for a touch with the opposite hand. They pass a beanbag around the waist, or ask for a high five with the “wrong” hand, which gets a laugh every time. Nobody is scored, and nobody is told they got it wrong. Each game is short, because the whole class is only 45 minutes.

A Word on Development

We’re a martial arts school, not therapists, and we never assess a child. If you have questions about how your child is moving or learning, the CDC’s “Learn the Signs. Act Early.” program offers free milestone checklists for parents to follow along with, and its guidance is to talk with your child’s doctor about any concerns. Your pediatrician is the right person to ask.

Try This at Home in Ten Minutes

• Clear a space, then do a slow bear crawl across the room, moving opposite hand and knee together.
• Stick a sticker on your child’s left knee and ask for a touch with the right hand. Then switch sides.
• Sit back to back and pass a stuffed animal around the waist, one way and then the other.

Keep it silly, and stop when it stops being fun.

Questions Parents Ask

What does crossing the midline mean for a preschooler?

It means reaching a hand, foot or eye across the middle of the body to the other side. Our Little Ninjas games, for ages 3 to 5, use bear crawls, cone touches and beanbag passes to practice it as play.

When is the Little Ninjas class at Flow Academy BJJ Riverside?

Mondays and Wednesdays from 3:45 to 4:30 PM, for ages 3 to 5. Classes begin once our new home opens in mid-November 2026.

What does my child wear to the first class?

Comfortable athletic clothes and a water bottle. The first class is free, and kids train barefoot on the mat. A gi comes later, if you decide to continue.

Our new Riverside home at 10081 Indiana Ave, Suite A-1 opens in mid-November 2026. Classes are paused during the remodel. Call or text (951) 337-3781, or join the Riverside interest list to hear from us first. If your family can’t wait, our Indio academy is running classes normally.