Project: Advancing Whole-Body Vibration (WBV) Exposure Control in Agriculture
Project Dates: 2022-2027
Research type: Basic/etiologic
Investigators and Students:
Nathan Fethke, PhD, CPE, Professor of Occupational and Environmental Health and GPCAH Deputy Director
Salam Rahmatalla, PhD, Professor of Civil and Environmental Engineering
Geb Thomas, PhD, Professor of Industrial & Systems Engineering
David Wilder, PhD, CPE, Professor Emeritus of Biomedical Engineering
Adam Ramker, MS student, Industrial & Systems Engineering
Arunabha Batabyal, PhD student, Industrial & Systems Engineering
Ethan Manuell, undergraduate student, Biomedical Engineering
Back pain is a major contributor to lost productive time among farmers engaged in mechanized agriculture, for which exposure to whole-body vibration (WBV) while operating machinery is among the strongest risk factors. A properly functioning seat suspension can minimize transmission of vibration from a machine chassis to the seated operator. When not functioning properly, a seat suspension may not adequately reduce (and instead may actually exacerbate) vibration levels.
This project will help to answer critical questions related to musculoskeletal illnesses experienced by farmers (low back pain) from WBV exposures during agricultural machine operation. Our team, comprised of recognized experts in the area of the human response to vibration and occupational exposure science, will develop and evaluate a low-cost sensor system to deploy for prolonged sampling in the field among a large number and variety of machines. Ultimately, one of the most important questions we want to address is “when does a seat need to be replaced?” The complexity of vibration measurements, combined with the influence of operator posture and operation parameters (terrain, speed, equipment) on WBV levels and seat performance, first requires basic investigation to create a method and metrics to assess seat performance in the field or at equipment suppliers/maintenance sites.
Specific Aim 1: Develop and validate a low-cost instrumentation system for measurement of WBV exposure levels and seat vibration attenuation performance.
Our prototype low-cost (<$300/unit) WBV measurement system will be refined and validated relative to ISO 8041-1 technical requirements. Our working hypothesis is that we will observe excellent agreement between measures of WBV exposure levels and seat vibration attenuation performance obtained with our system and those from reference instruments.
Specific Aim 2: Characterize the variability of agricultural machine seat vibration attenuation performance.
We will instrument 40 agricultural machines across 10 farm operations of ≥500 planted acres of row crops. Our goal is to record data from each machine each time it is used during the major phases of crop production. We will quantify between-day, between-operator, and within-operator contributions to the total variance observed in seat vibration attenuation performance. We will also observe the extent to which existing machine seats fail to attenuate vibration during agricultural production and identify which mechanical and biomechanical factors contribute the most to the variability in seat vibration attenuation performance over time.
Specific Aim 3: Estimate the effect of data sampling duration on the bias and precision of WBV exposure and seat vibration attenuation performance measures.
The data from Aim 2 will be used to simulate WBV sampling strategies of varying durations. Analyses will characterize the expected uncertainty in variables of WBV exposure levels and seat vibration attenuation performance as a consequence of sampling duration. Results will inform decision-making regarding WBV sampling duration in future research.
This project addresses Musculoskeletal Health cross-sector priorities for Agriculture, Forestry, and Fishing in the current NIOSH strategic plan. The predominance of mechanized agriculture in the GPCAH region enhances project alignment with regional needs and the Center’s mission. Ultimately, the methods developed and results from this project can be used to (i) design a field-based testing protocol for assessing seat vibration attenuation performance, (ii) inform modifications/amendments to ISO’s WBV standards, and (iii) make routine monitoring of WBV exposure levels and seat vibration attenuation performance more accessible to agricultural safety and health stakeholders for the purpose of preventing back problems among this high-risk occupational group.
While the WBV project is new, it builds naturally upon the 2011-2016 GPCAH study “Musculoskeletal Symptoms among Agricultural Workers,” which was also led by Dr. Fethke. That study included a substantial effort to characterize exposure to WBV and other physical risk factors using direct technical measurements during actual agricultural production. Key observations leading to the 2022-2027 study include (i) consistently high levels of WBV exposures measured during use of a variety of agricultural machines and (ii) a lack of data-driven approaches for owners, operators, or other stakeholders to assess the vibration attenuation characteristics of their machine seats. The 2022-2027 project will address this important gap, and brings together a team of internationally recognized experts in the measurement and evaluation of WBV and in the development of low-cost instrumentation systems.
Publications from the 2022-2027 WBV Study
When the project is further along and we have results to share, we’ll post information here about publications and presentations.
Related Publications using Data from our 2011-2016 GPCAH Study
Roeder SK, Wilder DG, Fethke NB. Novel methods to detect impacts within whole-body vibration time series data. Ergonomics (2022); 65:1609-1620. doi:10.1080/00140139.2022.2041735. PMID: 35148664.
Fethke NB, Schall Jr MC, Chen H, Branch CA, Merlino LA. Biomechanical factors during common agricultural activities: Results of on-farm exposure assessments using direct measurement methods. J Occ Environ Hyg. 2020;17(2-3):85- 96. doi:10.1080/15459624.2020.1717502. PMCID: PMC8328096.
Fethke NB, Schall MC, Merlino LA, Chen H, Branch CA, Ramaswamy M. Whole-body vibration and trunk posture during operation of agricultural machinery. Ann Work Expo Health. (2018);62(9):1123-1133. doi:10.1093/annweh/wxy076. PMCID: PMC8328096.
Related Presentations using Data from our 2011-2016 GPCAH Study (*presenting author, if other than 1st author)
Fethke NB, Gerr F, Merlino L, Branch C, Schall Jr MC*. Exposure to physical risk factors for musculoskeletal health outcomes during common agricultural activities. International Society of Agricultural Safety and Health Conference. Omaha, NE. June 22-26, 2014.
Fethke N. Associations between exposure to physical risk factors and musculoskeletal pain among agricultural workers. Occupational Hygiene in Agriculture – Roundtable Session. 2015 AIHce. Salt Lake City, UT. May 30 – June 4.
Schall Jr MC, Fethke NB, Ramaswamy M, Chen H, Branch C, Merlino L, Watabe J, Gerr F. Whole-body vibration among agricultural workers performing common agricultural activities. International Society of Agricultural Safety and Health Annual Conference. Bloomington-Normal, IL. June 21-24, 2015.
Related Press Releases/Media Stories/Podcasts
Gibbs J, Fethke N and Snee T:  Press release: With longer hours spent on farm equipment, whole body vibration and lower back pain is a concern to some farmers.
Fethke N:  Iowa: Operating Agricultural Equipment May Have Hidden Physical Consequences for Farmers. ASPPH Member Research and Reports. Aug 24. Available at https://www.aspph.org/iowa-operatingagricultural-equipment-may-have-hidden-physical-consequences-for-farmers/.