A therapy ball, often called a stability or exercise ball, is a specialized tool used by occupational and physical therapists to support a child’s development. These inflatable spheres provide an unstable surface that actively engages a child’s postural muscles and sensory systems. The ball is used to enhance core strength, improve balance reactions, and provide necessary sensory input for regulation. Selecting the correct diameter is the most important factor, directly influencing the effectiveness of the therapy and ensuring the child’s physical alignment is maintained during use.
Determining the Correct Ball Size
The primary guideline for selecting the appropriate size is the 90-degree rule, which focuses on achieving optimal seated alignment. When the child is sitting on the ball with their feet flat on the floor, both their hips and knees should be bent at approximately a right angle. This position ensures the child’s pelvis is level and their trunk is vertically aligned, facilitating proper weight-bearing and postural control.
If the ball is too small, the child’s hips will sit lower than their knees, restricting movement and compromising spinal posture. If the ball is too large, the child’s feet cannot rest flat on the floor, reducing stability and trunk control. The correct fit allows for the most beneficial engagement of core musculature during active sitting.
While a therapist is the best resource for precise sizing, a general guide links ball diameter to the child’s height. For most children under four feet tall, a 30-centimeter or 35-centimeter ball is appropriate. Children ranging from four feet to four feet, six inches often use a 45-centimeter ball. Taller children, up to five feet, typically require a 55-centimeter ball to maintain the proper knee and hip angles.
When a child falls between two standard sizes, it is better to select the smaller size to ensure the feet remain firmly planted on the floor for stability. However, for children with a higher weight-to-height ratio, the next larger size may be needed to account for the increased compression of the ball. The ball’s height should be checked to be no higher than the child’s knee when they are standing beside it as a quick initial measure.
Key Uses in Pediatric Therapy
A properly sized therapy ball is a versatile tool that encourages functional movement and better body awareness. One common application is dynamic sitting, where the ball serves as an active seating option requiring constant, small adjustments to maintain balance. This continuous engagement helps develop trunk stability and increase core strength, supporting better posture for tasks like drawing or reading.
The ball is also used for activities in the prone position, where the child lies on their stomach over the ball. Rolling the child gently back and forth provides significant vestibular input, which aids sensory regulation and body organization. Rolling forward onto the hands encourages upper body weight bearing, strengthening the shoulder girdle for fine motor skills.
Rhythmic bouncing while seated is another use, providing organized, repetitive movement that can be either alerting or calming. Fast, short bounces may increase alertness, while slow, gentle rocking often has a soothing effect. This makes bouncing useful for children who seek or need help processing sensory input.
Specialized Balls and Shapes
While the round therapy ball is the standard, specialized shapes exist to accommodate varying needs for stability. The most notable variation is the “peanut ball,” which is elongated with a saddle-like dip in the center. This unique shape provides more stability because it can only roll forward and backward, restricting lateral movement.
The restricted movement of the peanut ball makes it a safer option for children who have severe balance challenges or are new to ball activities. Its design allows a therapist or caregiver to sit comfortably on one end while the child is supported on the other, facilitating close physical support and guidance. This shared surface enhances confidence for the child while still providing the benefits of an unstable surface.
Therapy balls are constructed from durable, burst-resistant material, such as thick PVC, which is a safety feature. This material is designed to deflate slowly if punctured, rather than suddenly bursting, preventing a rapid fall. Some balls also incorporate varied textures on the surface to offer tactile sensory input.
Inflation and Safety Guidelines
Proper inflation is necessary to ensure the ball maintains its intended size and firmness for effective use. A therapy ball should never be over-inflated past its recommended maximum diameter, as this can make the surface too hard and reduce the beneficial “give.” The ball should have a slight amount of compression when pressed, indicating the correct firmness for optimal performance.
The amount of air can be adjusted to modify the activity’s difficulty. A slightly softer, less-inflated ball provides a larger base of support and is more stable. Conversely, a fully inflated ball compresses less, making it firmer and increasing the challenge to the child’s balance reactions. It is also important to check the ball’s weight limit to ensure it can safely support the child’s body weight.
Physical safety requires that the ball is regularly inspected for punctures, tears, or signs of wear before each use. The ball should be cleaned with a disinfectant as needed to maintain hygiene. A child must never be left unattended while using a therapy ball, as close supervision is required to prevent falls and ensure exercises are performed correctly.