4 Steps to Determine the Right Size for Your Electric Wheelchair

4 Steps to Determine the Right Size for Your Electric Wheelchair

When selecting an electric wheelchair, understanding its main dimensions is crucial for ensuring both safety and comfort. Key measurements include seat height, width, depth, seat inclination, backrest height, armrest height, and pedal height. Let’s explore how to determine the ideal size parameters for an electric wheelchair.

1. Seat Height, Width, and Depth

Seat Height: This is the distance from the upper support surface of the seat cushion to the ground at the wheel’s contact point. A higher seat can shift the wheelchair’s center of gravity, potentially causing instability and making it prone to tipping backward, forward, or sideways. For stability and comfort, the seat height should prevent thigh muscle compression and allow the calves to rest naturally on the footrests.

Seat Width: The width is determined by the hip and elbow measurements of a seated person. If the seat is too wide, the user’s elbows may extend outward, causing discomfort and shoulder fatigue. Conversely, a narrow seat can squeeze the body, compromising comfort and stability. An optimal width of around 445mm strikes a balance between support and maneuverability.

Seat Depth: Depth is measured to ensure a stable sitting posture and proper lumbar support, leaving a small gap between the back of the calf and the front edge of the seat. A short seat depth can concentrate pressure on the buttocks, causing discomfort, while excessive depth can strain the lumbar spine. A standard seat depth of 440mm, adjusted for body size, provides adequate support.

2. Seat Inclination

The inclination angle of the seat, measured relative to the horizontal plane, impacts user comfort during prolonged sitting. A slight tilt (between 4° and 8°) helps prevent sliding and supports the lower back. However, excessive inclination can cause lumbar strain and abdominal compression. A moderate tilt angle ensures proper posture and reduces injury risk.

3. Backrest Height, Width, and Inclination

Backrest Height: To accommodate varying needs, an adjustable backrest is ideal. The height, based on human body dimensions, must adhere to regulations, with the total wheelchair height not exceeding 1090mm. The backrest’s adjustable range typically spans from 460mm to 540mm.

Backrest Width: This dimension corresponds to the maximum shoulder width of the 95th percentile of women, with an adjustment for comfort, totaling 440mm.

Backrest Inclination: The angle formed between the backrest and the horizontal plane typically ranges from 95° to 120°. Research indicates that a 115° angle allows for optimal spinal comfort. For safety, a backrest inclination of 105° is recommended, creating an overall angle of 109° between the seat and backrest when the seat surface is tilted at 4°.

4. Armrest Height and Spacing

Armrest Height: This measures from the armrest’s surface to the seat base and is crucial for supporting arm weight and enhancing body stability. The ideal armrest height, calculated using the elbow height of a seated person, is set at 225mm to ensure ergonomic support.

Armrest Spacing: Comfort also depends on the distance between the armrests. The width is based on the 95th percentile elbow width of women, adjusted to 525mm for ease of use and maneuverability.

By understanding these essential size parameters, you can select an electric wheelchair that offers both safety and maximum comfort. If you need more assistance or wish to explore our range of products, feel free to visit www.jj-mobility.com.