Video: Shaking things up

Uncovering clues to alleviate bodily stress from heavy equipment vehicles

Jay Kim

Assistant Professor Jay Kim works in his lab

Last summer, a machine resembling an intergalactic metal spider made its home in the Women’s Building basement on Oregon State’s campus. Since January, the machine ­– which scientists call the Six Degree of Freedom (6-DOF) motion platform – has been busy shaking and jerking about.

As its platform rattles, the 6-DOF motion platform collects valuable data that is helping CPHHS Assistant Professor Jay Kim and his research team gather information that will reduce whole body vibrations (WBV) in heavy equipment operators. WBV is the measure of vibration that drivers experience through their seat or feet by workplace vehicles.

“The 6-DOF motion platform allows us to replicate the exact vibrations felt in the field in the lab, such as the working conditions mine workers experience” Jay says. “By using this system, we can now look at underlying injury mechanisms associated with WBV exposures by examining biomarkers and joint torques measured by a 3-D optional motion capture system. There are eight cameras collecting information that shows whether there is an increase in risk for spinal injuries and how much biomechanical loading is being applied to the musculoskeletal system.”

Industries shaken for years

Musculoskeletal disorders have plagued the construction, mining, transportation and agriculture industries for years. According to the United States Department of Labor’s Bureau of Labor Statistics, there were 6,190 nonfatal musculoskeletal occupational injuries or illnesses involving absences from work in Oregon in 2015 in the private industry and 660 in local government. Of the private industry injuries, 2,830 affected the back and 1,410 were specific to the lumbar region.

WBV is a leading risk factor for musculoskeletal disorders, especially low back disorders,” Jay says. “These disorders are the cause of 40 to 60 percent of all workers’ compensation claims in the nation, and the annual cost ranges from $20-$60 billion, which is almost the same as cancer.”

Unfortunately, the United States places no legal regulations on WBV exposure levels. Workers in European Union countries are protected by Directive 2002/44/EC of the European Parliament, which sets exposure limits and includes employer obligations to determine and assess risk. In British Columbia, Canada, if a heavy equipment operator experiences lower back pain, their doctor can prescribe a special WBV reducing chair developed by Bose to reduce exposure to vibrations.

Jay says that many drivers spend up to 70 hours per week in the driver’s seat. If you multiply that number by the typical 30-year career span, with a two-week vacation taken into account, the number of hours drivers could spend at the wheel is about 105,000, or 13,125 working days.

Examining biomarkers

“Up to this point, a lot of the research on WBV has been through epidemiological and field-based studies, and those studies have only shown the association between WBV and adverse outcomes,” Jay says. “But we don’t know the exact underlying injury mechanisms and etiology.”

Jay Kim

Jay’s prototype chair reduces features multi-axial vibration reduction

Jay and his team are looking to change that and have been using biomarkers in the blood – inflammatory responses and other stress indicators – to look at the exact relationships between the vibration and the physiological response from our bodies. This will make it possible to delineate the injury mechanism from WBV and low back pain and other musculoskeletal disorders. 

Looking toward the future

Nearly 75 percent of workers who operate heavy machinery suffer from low back pain. Jay hopes his research will have a significant impact on an industry that has been suffering for decades and that his studies provide the justification needed for improved seating for professional heavy equipment vehicle operators.

His most exciting discovery to date is a driver’s seat that would reduce WBV both vertically and laterally. There is currently a WBV reducing chair on the market called the Bose Ride® system. This “first-generation” chair reduces vibrations a driver feels on a single axis (up and down) by 50 percent.

Jay is currently testing what he calls the “second-generation” chair, which features multi-axial vibration reduction. Instead of simply moving up and down, this prototype also actively cancel lateral movements. This is especially significant for off-road vehicle drivers such as mining vehicles because these off-road vehicles have significant lateral vibration in addition to the vertical movements.

“The results are very promising,” he says. “It’s different from a conventional suspension system, which only has vertical suspension. This one also addresses lateral movement, and semi-trucks and off-road heavy equipment vehicles have a lot of rolling motion, so a multi-axial suspension system will greatly reduce the total dose of WBV exposures. By showing that engineering interventions can save drivers’ backs, more seat and truck manufacturers can start building more accessible and affordable seating technology to reduce such significant occupational hazard.”

Get involved

Jay currently has three externally funded research projects under way and is actively seeking study participants. If you’d like the opportunity to be involved in Jay’s research to help shape the future of the heavy equipment industry, contact him at jay.kim@oregonstate.edu or call 541-737-2166.

Jay Kim

Jay hopes to see accessible and affordable seating technology on the market in the future