Last updated on May 15th, 2025 at 05:04 pm
Differently abled children, those who have difficulty with sitting balance ( cerebral palsy, a child with abnormal muscle tone). Can be benefited by using a therapy ball (gym ball) in an effective way to develop their sitting balance.
One question that frequently comes to mind for many parents is: “What size exercise ball should I purchase, which can help to develop my child’s sitting balance?”
In this article, we will address this important topic and provide you with research-based guidelines to make the right choice.
The 90-Degree Rule: The Key to Proper Positioning
When we are trying to develop the sitting balance in kids, we have to follow the 90-degree rule. That means the main joints of the hip and lower limb should be at a 90-degree angle. It should not be less than or more than this angle.
So, let me explain what it means.
When we are giving therapy to develop sitting balance on a therapy ball, the ideal position of a child on the therapy ball, to have their ankles, knees, and hips all at 90-degree angles.
This position ensures that when the child is sitting, the child’s centre of gravity falls in front of the child. If it is behind the child, then it negatively impacts the spine, and the child may tend to slide backward and fall.
This positioning creates the optimal foundation for developing core strength and balance.
How to Measure for the Perfect Fit
The process of finding the right ball size is straightforward. Here’s a simple method to determine the ideal diameter:
- Have your child fold their arm straight out from their body as shown in the figure.
- Measure the distance from their sternum (breastbone) to their wrist
- This measurement should equal the diameter of the exercise ball
This measurement technique ensures that when sitting on the ball, your child will naturally achieve those important 90-degree angles at the ankles, knees, and hips.
A Practical Demonstration
Let me share a personal example. If I want to develop my own sitting balance and core strength, I need to follow the same principles.
When I sit on a ball that’s too small or too large, my body can’t maintain those critical 90-degree angles. My ankles, knees, and hips end up at awkward angles that don’t support proper posture or effective balance development.
However, when I sit on a ball of the perfect diameter—where the distance from my sternum to my wrist matches the ball’s size—my body naturally aligns with ankles, knees, and hips all at 90-degree angles.
This position creates the ideal foundation for stability exercises and balance development.
Benefits of Using the Correctly Sized Exercise Ball
Using an appropriately sized exercise ball offers numerous benefits:
- Promotes proper posture from an early age
- Strengthens core muscles as the body works to maintain balance
- Improves proprioception (awareness of body position in space)
- Enhances coordination through gentle, controlled movements
- Makes therapy exercises more engaging for children
Conclusion
Selecting the right size Therapy ball makes a significant difference in the effectiveness of balance training. By following the guidelines shared in this article—ensuring your child’s ankles, knees, and hips form 90-degree angles when seated—you’ll create the optimal environment for developing strong sitting balance.
At Sama Foundation, we’re committed to providing evidence-based guidance for your child’s development. For more information or personalised advice, please reach out to qualified therapists nearby, or you can approach our team of pediatric therapists.
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Dr.Mohd Yoosuf has spent nearly 25 years working with Differently abled children .He is a compassionate,friendly, caring occupational therapist, who love to help these ignited mind to reach their goals within their limitations.
His journey began with a simple wish: to make a real difference. He earned a college degree with a Bachelor's in Occupational Therapy (BOT) from one of the prestigious Central Government institutes, i.e. SVNIRTAR. Then he worked with children with special needs and then got a master's degree(M.O.Th in Pediatrics)from pioneer University(JAMIA HAMDARD). Which gave him the knowledge and skills to understand each child's unique needs.
Dr Mohd Yoosuf never stopped learning. He updates his knowledge on the latest development in Occupational Therapy by attending CMEs, workshops,seminars. He has a degree on special program from the University of Southern California. Presently he is pursuing PhD in Occupational Therapy(Pediatrics)
He has contributed to the society to empower the special population by manufacturing innovative and cost effective sensory integration and Neurodevelopmental therapy equipments.
He has contributed to the RBSK (Haryana Chapter) as Knowledge Partner.
He has written a few articles in Newspaper for the New generation about this novel(Occupational Therapy ) Profession.
He cares deeply for these special children and wants to do more for them. He started a special school named Shama Foundation where children with special needs can learn and grow in a safe and supportive environment. He also helped bring aqua therapy, a fun way to exercise in water to Delhi for the first time, giving children another option for getting stronger.
Because of his dedication, Dr Yoosuf has received award in Neuraxis 2018 and has been asked to join important groups that help make decisions about caring for children with special needs.
Dr Yoosuf is a wonderful example of a dedicated professional. His kindness and innovative ideas have made a big difference in the lives of many differently abled children and families in India.
