Remember when your mother used to nag you, when you were a child, to sit up straight? Turns out she may have been onto something. When kids constantly slouch, it may indicate a more serious underlying issue. “When we slump over, we can't learn about the world as well,” says Carol Stock Kranowitz, author of The Out-of-Sync Child: Recognizing and Coping with Sensory Processing Disorder (Peregrine Trade, 2006).

Often, posture problems signal that the vestibular sense may not be communicating well with the central nervous system. The vestibular system refers to our sense of balance—it tells us where our heads and bodies are in relationship to the ground. “This system takes in sensory messages about balance and movement from the neck, eyes and body; sends these messages to the central nervous system for processing; and then helps generate muscle tone that allows us to move smoothly and efficiently,” Kranowitz writes in The Out of Sync Child.

Recognizing the red flags

For a child whose vestibular sense has been compromised, he may always have struggled with the postural adjustments needed to stay upright. He may have skipped crawling or been a late walker. He may slump when he sits, sprawl on the floor and lean on his hands when he's at the table. His muscle tone is low—and perhaps his affect is too—as the brain isn't giving the muscles the energizing messages they require. “There's no oomph—it's like they have novocaine in their limbs,” says Kranowitz. 

When the muscles are weak, motor planning, or praxis, can seem enormously challenging. Praxis, the ability to organize and execute a complex sequence of unfamiliar movements, comes into play whenever we need to learn a new physical skill set, such as how to ride a bike or ice skate. If you don't really know where the body is in space, motor planning proves tricky. Children who struggle with physical activities often struggle with low self-esteem as well. They tend to give up easily and avoid trying new things. 

Children who are off-kilter physically may have corresponding emotional issues. “Kids with poor posture, whose spines slump, subdue their sympathetic and parasympathetic nervous system responses,” says Avigail Roberg, founder of Daisy Organization of Interdisciplinary Therapies. “They usually have problems regulating their moods and transitioning from one activity to the next.”

Pinpointing the causes

Like with many neurodevelopmental disorders, the exact cause of sensory integration issues has not been identified, but their prevalence may surprise you. According to a study published in the January 2009 issue of the Journal of Abnormal Child Psychology, one in every six children experiences sensory symptoms significant enough to impact daily life. Many occupational therapists speculate that part of the problem, which may also be genetic, could be a lack of free play from infancy up through adolescence. 

“What we have now are 'containerized' kids,” says Kranowitz. “They spend their days in car seats, in cribs, in strollers—bucket babies. We don't take enough time to let our children be free and on their tummies, which is critical for future posture. We need to get kids out of their strollers and get them involved in physical work.” 

Therese Sullivan, an occupational therapist based in South Bend, Ind., agrees that sedentary lifestyles from an early age compound the problem. “Free physical play from an early age is enormously beneficial, as physical development occurs through experience. This can't be overstated,” Sullivan says. “Young kids need space to run, jump and play.”

The pattern emerges

If you suspect that your child doesn't show age-appropriate interest in movement, trust your instincts. “Parents are great detectives,” says Kranowitz. “Rather than let it slide, ask yourself if your kid’s behavior is a little unusual.” Use this abbreviated checklist from The Out-of-Sync Child to gauge whether your child's behavior may be part of a larger pattern of sensory challenges. The child who has problems with posture, movement and balance may:

• Easily lose her balance
• Move in an uncoordinated, awkward way
• Have a loose and floppy body
• Fatigue easily
• Sit on the floor in a “W,” i.e., with her knees bent and her feet extended out to the sides to stabilize her body
• Have difficulty turning doorknobs and handles that require pressure

To assist your child, there are plenty of ways to be a part of the solution. “Don't underestimate the value of child-sized furniture,” says Sullivan. “Tables and chairs that adjust to your child's height support their posture and allow for good muscular feedback.” 

You can help your child gain more mastery of his body by emphasizing bicycling, climbing or even hiking on uneven terrain. “Devising games, such as obstacle courses, can let your child develop better economy of motion—while having plenty of fun,” says Kranowitz. 

Getting your child an occupational therapy evaluation and further treatment if recommended will make, if not a crucial difference, a welcome one. “Good sensory processing feeds the brain: motor planning, focus, executive function, social skills,” says Sullivan. “We live in a physical world, and to find our comfort level in the world, we have to be comfortable in our skin."