How prolonged driving impacts posture?
Poor posture and driving ergonomics can lead to discomfort after a lengthy car ride, but in the long-term, its effects on the body are even more demanding. Over a period of driving for prolonged hours, there is a big chance of developing postural distortions or compensatory body patterning. These can then lead to musculoskeletal injuries such as upper body dysfunction, lower extremity dysfunction and lumbo pelvic hip complex dysfunction, each of which can manifest in the constant driving. Other than musculoskeletal injuries, disc related issues in the lower back and neck can also develop due to constant pressure placed at these body parts. Keeping the disc(s) in flexion position for long periods of time causes the spine to curve which can lead to chronic pain and, ultimately, injury/damage if not treated immediately.
Another factor that can cause postural concern is the setting of the vehicle’s seating in a position that is not ideal for the driver’s body. For example, the low position of a vehicle seat as well as an inclined back rest may prevent the angles of the hips and knees from being in line. This concern has been noted as early as the 90’s when researchers started to notice that the vehicle’s seat design and driver’s sitting posture significantly affect the driver’s comfort. Specifically, ergonomically unfit seating positions exposed truck drivers to numerous health problems.
Similarly, a study conducted by Wilder et al, 2016 postulated the theory that the ergonomic design of truck driver’s seat is an important issue for the vehicle design engineers, as truck drivers usually spend over 2,400 hours on the road in a year. In addition, the seat dimensions and anthropometric measurements for nearly all truck brands and the existing seat dimensions were found to be inappropriate for truck drivers (in Bangladesh) and causing health problems. A study stated that seat discomfort was highly associated with low back pain. Drivers who reported uncomfortable seats exhibited 8 times higher risk for developing low back pain than those reporting comfortable sitting positions. Likewise, drivers who complained about the positions of their steering wheels had higher incidences of low back pain than those not reporting uncomfortable steering wheels.
Finally, changing gears in both manual (primarily) and automatic cars can also affect musculoskeletal issues in the shoulder and neck, resulting from the gear stick position on a single side. To accommodate this problem, the driver needs to adjust the chair to the ideal position in order to the gear stick in a neutral position – neither reaching to a straight arm, nor bending beyond 90 degrees.
Is sitting in a car seat the same as sitting in a chair?
It is important to note that sitting ergonomics in a car and sitting on a normal chair are fundamentally different, in particular due to the activities taking place. When seated in a car, the hands and arms are typically higher than when working at a desk. To operate the brake and accelerator pedals, the driver’s legs are farther forward. In some cases, one foot may be flat on the floor and the other at an angle to operate the accelerator and brake pedals, whereas for manual transmission, the other foot is on the clutch and one arm and hand is needed to operate the gear shift.
In addition to this, vibrations coming from the moving vehicle contribute stress to the lower back coming from the moving vehicle on an uneven or bumpy road surface and the body moves sideways when taking on corners. Depending on how fast the vehicle is accelerating or decelerating, there is a variable force that is exerted on the driver’s body. Of course, these moving forces are not present when working at a desk, causing very different challenges for the body.
Ergonomics risk factors associated with low back pain
Ergonomists around the world have identified some of ergonomic risk factors related to musculoskeletal disorders (MSDs) such as repetitive work, work in extreme pressure conditions and postures, vibration, and work with forceful movements. For driving ergonomics, the most common musculoskeletal disorders seen is low back pain. Worldwide, 37% of the incidence of low back pain is attributed to work-related or occupation-based causes. There is evidence by many researchers that MSDs and, especially low back pain, affect in particular driver occupational workers. A study stated that professional drivers have been found to be at high risk of developing low back pain and the prevalence of low back pain was more than 50% in developed and developing countries. As mentioned above, the physical factors experienced by drivers such as prolonged sitting, whole body vibration, the ergonomic mismatch between anthropometric sizes of the driver and their physical environment, and even the type of vehicle seat increase the risk of developing low back pain.
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It was found that 81% of American bus drivers and 49% of Swedish bus drivers had reported low back pain. In Malaysia, a study showed a high prevalence of low back pain among bus drivers of 60.4%. Total working time has also been found to be correlated to the occurrence of low back pain due the effect on the prolonged sitting. It is believed that when the drivers are passively sitting, the lumbar spine is poorly supported and may actually expose them to sudden injuries. The long working periods without adequate rest directly contribute to the low back pain. It has been found that driving more than twenty hours a week has a significant contribution to the high prevalence of low back pain and also to medical leave. The risk of low back pain is higher when drivers work about 30-50 hours per week compared with drivers who work less than 30 hours. In fact, the risks are up to five times greater for those drivers who work more than 50 hours per week. This is particularly interesting given that other findings discovered that even driving more than 20 hours in a week has the possibility to lead to low back pain. It further showed that awkward bending and prolonged static posture has been reported to cause low back pain, as the static compression of the cells in the disks is linked to an increase in cell death.
In a survey conducted by Rehamed Therapy amongst it’s patients, we found that although almost one of every three people (29.7%) suffered from discomfort during driving, less than half (14.3%) of these ever sought treatment for such injury. Interestingly, about 35% of respondents mentioned that they were aware of driving ergonomics, although it may be that a significant portion of these learnt about it following their injuries.
With regards to their driving behaviour, approximately 85% of those surveyed mentioned they drive at least every second day, of which 51% drive every single day. However, most people (about two thirds) drove less than an hour per day on average which corresponds with the probability of driving pain-free, supporting the results that driving injury is proportional to total driving time. Finally, almost 90% of the patients surveyed mentioned they were physically active, which might be surprising given the relatively high discomfort rate (30%). This clearly further highlights the importance of driving ergonomics on overall health.
Ways to Minimise the Risk
- Seat Height
- Raise the seat to ensure the driver has maximum vision of the road.
- Ensure there is adequate clearance from the roof.
- Lower Limb Position
- Knees should be bent, in order to comfortably operate the accelerator/clutch and brake.
- The steering wheel should not come into contact with the top of the legs.
- Seat Pan
- Thighs supported along the length of the cushion.
- Avoid pressure behind the knees.
- Back Rest
- Adjust the backrest so it provides continued support along the length of the back. Shoulders slightly behind the hips.
- Lumbar Support
- The lumbar support whether adjustable or not, should provide comfort with no pressure points or gaps between the spine and car seat.
- A S-shape spine is a safe shape.
- Steering Wheel
- All objects and controls should be in easy reach to prevent unnecessary reaching.
- Elbows and shoulders should be in a relaxed position with hands positioned below shoulder level.
- Check for clearance of thighs and knees (allow 2-4cm)
- Ensure display panel is in full view and not obstructed.
- A good test is to put your arms straight in front (above the top of steering wheel), the top of the wheel should sit at approximately wrist level.
- The neck should be in a neutral position, with the headrest positioned centrally behind the head.
- Adjust the rear view and side mirrors to ensure adequate vision of surrounding areas.
Musculosketal Disorders (MSD’s)
- During breaks (15 minutes every 2 hours) incorporate postural variation e.g. stretches, walking around car etc.
- Make small adjustments to driving posture every 30-60 minutes.
- Practice correct manual handling techniques when taking items in/out of the vehicle.
- Ensure you get a 7-8 hour quality sleep the night before driving.
- Aim to not travel more than 8 hour per day.
- Take a 15 minute break every 2 hours.
- Where possible, alternate driving with your colleagues or with non-driving tasks.
- Heat can increase feelings of fatigue, therefore fresh cool air and music act as a short-term strategy in improving alertness.
- Vibration forces can be decreased with thick, firm foam car seats, which can absorb some vibration as it passes through.
- If possible, it is important to alternate driving tasks with non-driving tasks, to reduce the vibration exposure.
- Maintain a neutral spine; your spine is better able to observe shock when the lumbar curve is being maintained in a neutral position, compare to a flexed lumbar spine position sit up straight.
- Ensure tyre and suspension systems are maintained.
Do not make the mistake of taking Google’s word as scripture, consult a therapist now. If you want to know more about Driving Ergonomics, feel free to give us a call at 03-50315946 or send us a Whatsapp or Make an Appointment. We at Rehamed Therapy are always here to help!