Reports of musculoskeletal discomfort are prevalent among professional drivers – truck drivers, machine operators, couriers etc – and the risk of low back pain is known to be higher than average. Drivers generally experience several musculoskeletal disorder risk factors including exposure to whole-body vibration, sedentary work and awkward sitting postures. Underlying these physical risk exposures may be industrial issues, psychosocial factors and personal preferences which can motivate workers to raise concerns about particular work vehicles. This multifactorial problem can create significant challenges for safety and health professionals when trying to assess risk, manage injury and provide solutions.
Determining which of these factors needs to be addressed in the management of a worker with low back pain can be incredibly difficult. Establishing the presence or absence of vehicle-related physical risk factors such as poor ergonomics, is a relatively simple and objective process compared with the complexity of addressing psychosocial risk factors. This paper focusses on the occupational environment and provides safety and health professionals with awareness of the factors that may be implicated in back pain reports among drivers and what support or ergonomic improvements may be offered.
The prevalence of LBP among industrial drivers is considered to be higher than the population average. [i] [ii] [iii] [iv] While there is ample evidence to show an association between industrial driving and back pain, it is difficult to establish causation. What is it about driving that increases the likelihood of developing LBP?
Causative factors implicated in the development of musculoskeletal disorders are widely known to include exposure to:
- Repetitive or sustained force, [v]
- High or sudden force,
- Repetitive movement,
- Sustained or awkward posture,
Industrial drivers may experience several risk factors including significant duration of exposure to sustained sitting, awkward sitting postures and whole-body vibration (WBV). [vi] They may also experience exposure to risk factors outside of their driving time, particularly with materials handling[vii] as might be the case for a courier driver or forklift operator.
Establishing the presence or absence of risk factors in driving is essential in determining whether there is an occupational risk, and if so, to ensure appropriate risk controls are implemented. So, to establish the presence or absence of occupational risk for industrial drivers, three questions arise:
- How much WBV is too much?
- What constitutes an awkward driving posture?
- What duration of sustained sitting for driving is too much?
Whole body vibration
Until 2015, the only way to establish whether a vehicle or fleet of vehicles exposed workers to potentially harmful levels of WBV was to engage a specialist vibration engineer to conduct time-consuming and expensive testing; testing that was typically conducted sporadically and in an ad hoc manner. Burgess-Limerick and Lynas[i], with support from the Minerals Industry Safety & Health Centre, developed an iOS app to measure WBV exposure. With the wide availability of smart phones equipped with an accelerometer, access is supported for frequent and cost-effective WBV measurement.
Findings from WBV assessment of different machines and vehicles is dependent on a multitude of factors including driving speed, terrain, tyre pressure, vehicle loading and more. Table 2 shows WBV measures from an audit conducted for a Queensland construction company across a range of machines. Graphs indicate exposure extrapolated for driving durations of 4 hours, 8 hours and 10 hours depending on the typical work requirements.
The findings from this audit resulted in the employer changing their procurement processes. There were noteworthy differences in quality of vibration dampening as well as cabin ergonomics between vehicle models. Interestingly, the more expensive machines were not necessarily associated with superior ergonomics. The employer arranged for task rotation among workers and planned for multi-skilling workers to further encourage rotation. Some machines underwent maintenance that improved the vibration dampening. Training was offered to workers in the use of seating adjustment and optimal ergonomics. Training was also offered by the in-house fitter mechanics and this involved teaching machine operators about how to improve machine settings and timing to reduce vibration. Finally, the employer also committed to include ergonomic assessment as part of future vehicle procurement.
Should action be required, the implementation of risk controls should be considered as part of the broader manual tasks risk assessment and the hierarchy of risk controls applies.
- Reducing or eliminating WBV at the source is preferable.
- Engineering options may be directed at vehicle suspension, seating suspension, vehicle maintenance, and procurement specifications.
- Administrative controls may include reduction of driving duration, training drivers in seating adjustments, setting of speed limits, and driving to conditions.
For further information and answers to questions 2 and 3, click on the conference paper presented by Back On Track’s Principal Consultant, Leanne Loch. Visions Conference Vehicle Ergonomics Paper
[i] McGlothlin J, Burgess-Limerick R, Lynas D (2015) An iOS application for evaluating whole-body vibration within a workplace risk management process. Journal of Occupational and Environmental Hygiene 12(7):D137-142
[i] Bovenzi M, Rui F, Negro C, D’Agostin F, Angotzi G, Bianchi S, Bramanti L, Festa G, Gatti S, Pinto I, Rondina L, Stacchini N (2006) An epidemiological study of low back pain in professional drivers. Journal of Sound and Vibration 298: 514-539
[ii] Okunribido OO, Magnusson M, Pope M (2006) Delivery drivers and low-back pain: A study of the exposures to posture demands, manual materials handling and whole-body vibration. International Journal of Industrial Ergonomics 36(3): 265-273
[iii] Joy J, Mabarak N, Nelson S, Sweerts de Landas M, Magnusson M, Okunribido O, Pope M (2005) Whole body vibration and posture as risk factors for low back pain among forklift truck drivers. Journal of Sound and Vibration 284: 933-946
[iv] Okunribido OO, Shimbles SJ, Magnusson M, Pope M (2007) City bus driving and low back pain: A study of the exposures to posture demands, manual materials handling and whole-body vibration. Applied Ergonomics 38(1): 29-38
[v] Safe Work Australia (2016) Hazardous Manual Tasks Code of Practice
[vi] Okunribido OO, Magnuson M, Pope MH (2006) Low back pain in drivers: The relative role of whole-body vibration, posture and manual materials handling. Journal of Sound and Vibration 298:540-555
[vii] Okunribido OO, Magnuson M, Pope MH (2006) Low back pain in drivers: The relative role of whole-body vibration, posture and manual materials handling. Journal of Sound and Vibration 298:540-555
[viii] Videman T, Battie M (1999) The influence of occupation on lumbar degeneration. Spine 24(11): 1164-1168
[ix] Govindu N, Babski-Reeves K (2014) Effects of personal, psychosocial and occupational factors on low back pain severity in workers. International Journal of Industrial Ergonomics 44: 335-341
Full conference paper: Visions Conference Vehicle Ergonomics Paper