What is the correct posture in a wheelchair?

What is the purpose of a wheelchair? Basically, its function is to provide a user with reduced mobility with greater functionality and mobility in their daily lives, which is why it's so important to be comfortable and maintain good posture .

To ensure that a wheelchair meets all the needs of a person with disabilities, certain components of the chair must be adapted to make it the ideal companion, especially when it will be for permanent rather than temporary use. An inadequate wheelchair can lead to additional disability .

Below, we'll tell you what you should pay attention to when choosing a wheelchair and understand the correct posture to facilitate comfort for frequent users, as well as what factors to consider and/or avoid.

What factors affect the mobility of a wheelchair user?

The weight and construction material are among the factors that most affect a wheelchair's mobility and maneuverability. However, there are other important factors, such as the seat, wheel size, wheelbase, armrests, footrests, whether the chair is foldable or electric, and a number of other factors that will be decisive in optimally meeting the user's needs and experience.

Wheelchair mobility and friction

The greater the friction, the greater the rolling resistance of a wheelchair, so the user will need to exert more energy to move around.

Weight distribution between the front and rear wheels is also important. The greater the weight on the front wheels, the greater the friction, and while the chair will be heavier to move, it will be more stable for the user.

In a standard-class wheelchair, the weight is distributed equally across each wheel, while in an adjustable wheelchair, the weight is distributed 80% across the rear wheel and 20% across the front. In this sense, a standard wheelchair will roll better but will be less stable. However, the terrain you ride on will also impact the wheelchair's performance.

• What is the terrain like where the chair will be used? Soft ground will produce greater friction, and the effort required to propel the chair will be greater. On hard surfaces, however, friction will be less.
• What size and composition should the wheels be? Inflatable wheels are more comfortable and provide better rolling cushioning, but they increase rolling resistance because they are softer. This resistance is reduced with solid wheels.

Regarding proper posture, it is a fact that each individual, within their capabilities, adopts a particular posture when using a wheelchair. This will depend on several factors, such as their degree of disability, skin sensitivity or tolerance, their level of mobility, and also whether they need assistance or will move on their own.

Why is it important to adopt a proper posture in a wheelchair?

• To protect the integrity of the skin as a barrier against possible infections through injuries such as bedsores or pressure ulcers.
• In order to have a correct distribution of body weight.
• To prevent unnecessary muscle contractures and numbness.
• As a method of preventing pressure and friction on the skin when sitting, getting into position, or transferring to bed.

What does proper wheelchair ergonomics entail?

• The knees and hips should be at an equal and correct angle.
• The buttocks should be supported against the back of the seat and centered.
• The pelvis should have a slight forward tilt for greater movement.
• The pelvis should not have lateral inclinations.
• Shoulders should remain relaxed and arms free.
• The head will be straight with the chin tilted slightly downward to allow cervical movement.
• The feet should remain free and parallel to the floor.
• You should try to sit upright and in a symmetrical position.
• It is necessary to achieve maximum functional capacity, but with minimum energy expenditure.
• The pressure on the buttocks and thighs should be kept to a minimum. Specially designed therapeutic cushions for wheelchairs are available.

What size should a wheelchair seat be?

Having a good seat will help relieve pressure and distribute body weight evenly. If the seat is too wide, the user will tend to sit unevenly, and if it's too narrow, they run the risk of developing bedsores.

It should also be noted that if the seat is too short, the thighs will not be supported along their entire length and more pressure will accumulate in the buttocks area.

However, if it's too long, it could cause tension behind your knees. It will also be more difficult to access the proper support of the backrest, as it will tend to slide to avoid tension.

The ideal size for a wheelchair seat should be one that, when the user is properly seated and upright, leaves a distance of approximately two fingers between the inside of the knees and the edge of the seat.

What is the correct seat shape and angle?

When it comes to a wheelchair seat, the most important thing is that it's level and firm. A seat with sagging padding will create an asymmetrical posture and create friction, pressure, and moisture between the thighs and knees, potentially affecting the skin.

To achieve proper posture in a wheelchair during everyday life, you should try (if possible) to maintain a 90-degree angle. The best way to achieve this is to use a cushion that adapts to each person's ergonomics and aligns and accommodates the body naturally.

How to choose a wheelchair cushion?

While there are a wide variety of cushions and pillows to help reduce friction and excess pressure on bony prominences and the skin, the reality is that each style of therapeutic product will depend on each individual and their specific needs. Initially, choosing the most appropriate one will require considering the material it's made of.

Foam cushions

Cushions and pillows made of memory foam have the advantage of being very lightweight and adaptable to any location where they are needed. They feature a breathable fabric covering that prevents excess heat and moisture from accumulating. They last a long time, making them a good investment in comfort.

Air cushions

These types of pillows and cushions are made with small air cavities inside. This helps distribute body weight better compared to memory foam products. The downside is that they are more prone to puncture and will require replacement.

Gel cushions

In addition to being made with a memory foam base, they also contain small gel capsules for better weight distribution, heat reduction, and to prevent pressure sores and moisture.

Consider appropriate foot and arm supports

Once the 90° angle at the hip is achieved, most wheelchair users will feel truly comfortable if their knees are also positioned at a 90° angle. Since it's important for the ankles to maintain this angle, ergonomically speaking, it's recommended that the footrests also be at a 90° angle.

For a sports chair with smaller front wheels, the angle should be approximately 85°. For standard chairs, it should be slightly lower, but still close to 90°.

On the other hand, if you are a long-legged user, the footrest should be angled lower so that these platforms do not hinder your circulation.

Armrests are necessary to provide relief for the arms and neck muscles. They are properly adjusted when the user's forearms are at a 90-degree angle to the elbow.

If the armrests are too high, the shoulders will be forced upward, which could cause muscle pain in the cervical area. Conversely, if the armrests are too low, the user will tend to fall to one side when using them.

As an extra note: A stable seat base or a suitable ergonomic cushion could eliminate the need for adjustable armrests for active users.

What is the ideal height for a wheelchair backrest?

The backrest should be high enough to maintain stability in the user's upper lumbar region. Depending on the specific needs of each user, the backrest height may be higher.

For example, for people with spinal cord injuries, the larger the injury, the higher the backrest should be to provide adequate support to the trunk.

A higher backrest is also often recommended to provide security for a first-time wheelchair user. Once you get used to it, and if your injury allows, you can upgrade to lower backrests that will offer greater freedom of movement for your back.

What shape and angle should the backrest have?

It's proven that most wheelchair users will feel more comfortable if they have a backrest that provides adequate support for the lumbar region, as the shape of the backrest, combined with a proper angle of inclination, will provide better support and greater balance for the upper body.

It is recommended that the backrest be slightly tilted, so that the force of gravity falls on the user's chest and helps them stay stable. If the backrest is completely straight, the force of gravity will fall on their shoulders, causing them to lean forward to compensate.

It is also indicated that a backrest that is too reclined will be uncomfortable as the user's field of vision will be reduced.

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