Lift Teams—Share the Load:
Missing Pain Instead of Missing Work
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Digital rendering of a bricklayer lifting a block while hooked up to “motion capture sensors.” |
It is well known that masonry is hard work and stressful on the body. Musculoskeletal disorders such as sprains and strains are among the most common injuries to construction workers such as bricklayers. In fact, masonry workers have the highest rate of back injuries causing days away from work among all the trades. The rate is more than one-and-a-half times higher than the average rate for all construction workers, according to
a report by CPWR.*
During a safety and health workshop at the BAC Local Leadership Seminar, Local officers and staff provided researchers with comments on their initial findings from a study of lifting practices, as well as suggestions for changing work practices so that bricklayers are able to enjoy longer and healthier careers.
Research Findings
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Dr. Jennifer Hess of the University of Oregon Labor Education and Research Center discussing options for reducing musculoskeletal disorders during a workshop with BAC Local officers and staff. |
Drs. Dan Anton and Ryan Mizner of the Department of Physical Therapy at Eastern Washington University, and Dr. Jennifer Hess of the University of Oregon Labor Education and Research Center, conducted a multi-year study to evaluate different ergonomic solutions, or “controls,” for making masonry work safer. The first step of this process was to determine what ergonomic solutions were currently being used in the field. Masonry craft workers and contractors throughout the United States completed a survey about the controls used in their respective areas of the country. The various controls were categorized by different tasks and components such as mortar mixing, supply stack height, material handling, grout delivery and rebar placement. Ergonomic controls that could possibly decrease back injuries and other musculoskeletal problems included using H-block with rebar, silos for mixing mortar, adjustable scaffolding, grout delivery systems and using lift teams for heavier block.
Based on the survey results, the research team decided to study the effectiveness of a two-mason lift team for laying heavier CMUs.
Video Games Meet Research
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An apprentice bricklayer ready to begin work wears motion capture sensor markers that will allow researchers to record the position of his back and arms to detect stressful positions as he works. The research was conducted at the BAC/IMI Apprenticeship Training Center in Seattle, Washington. |
To study the lift team, the researchers recruited several apprentice bricklayers from a regional training facility to participate. Each apprentice built a wall six courses high and six blocks wide, one time individually and once in teams. They used 12-inch blocks that weighed about 50 pounds to construct each wall. During construction, the apprentices wore “motion capture sensors” similar to those used in the video gaming and movie industries. The ‘motion’ information captured was used to measure the position of the back and arms of each apprentice to help determine stressful positions. Anton and colleagues also measured how hard the apprentices’ muscles were working using a device called ‘electromyography’ or EMG. EMG sensors were placed on the lower back, upper back and forearms to record the stress to the muscles in those areas during building.
So, did lift teams stand up to the scrutiny of science? Researchers found that, compared to building a wall alone, a lift team reduces low back muscle force—and that could lead to fewer back injuries. They also discovered that the apprentices in a lift team did not have to bend forward as much as when lifting alone, although there was more twisting and side bending. For the shoulder, the results were mixed. When in a lift team, less shoulder stress was found on the side that held the trowel, but there was increased stress on the other shoulder at higher courses. Overall, the apprentices in lift teams spent less time at higher levels of muscle exertion than when working alone. Dr. Anton remarked, “Although the results were not all positive, there is enough evidence to show that lift teams may still be an effective way to reduce back injuries in the masonry profession, especially when lifting around waist level.”
Learning the Technique
The lift team technique is fairly simple and likely takes little time to master. Each bricklayer on a lift team plays a different role. One is in charge of completing the placement of the previously laid unit while the other prepares the next block. When ready, they lift the block and place it on the wall together. When done correctly, there is little to no waiting time for either bricklayer, and the reduced load for each will likely diminish fatigue over the course of the job. In fact, the research trials also revealed that two bricklayers in a lift team built the wall in 37% less time than when one bricklayer built the same size wall.
“We have heard journey-level bricklayers say that during a work week, a lift team is bound to be more productive,” said BAC Executive Vice President Henry Kramer. “A bricklayer working alone gets more and more fatigued by lifting and placing these large CMUs. We know that workers who push themselves when they are tired are more likely to make mistakes or injure themselves from overexertion.”
Since the lift team technique is more easily understood visually, Paul Moraski, a physical therapy doctoral student at Eastern Washington University, created an instructional video. This video can be found at BAC’s website (http://www.bacweb.org/safety_training/sh_video_two_mason.htm).
*References: CPWR – The Center for Construction Research and Training. The Construction Chart Book, 4th edition. Available at: http://www.cpwr.com/rp-chartbook.html.
This article was written by Paul Moraski for the BAC Journal and used findings from research conducted by Drs. Dan Anton and Ryan Mizner of Eastern Washington University, and Dr. Jennifer Hess of the University of Oregon. Their research was funded by CPWR – The Center for Construction Research and Training, using grant U54 OH008307 from the National Institute of Occupational Safety and Health (NIOSH). The contents are solely the responsibility of the authors and do not necessarily represent the official views of NIOSH.
CPWR is a 501(c)(3) nonprofit research and training institution created by the Building and Construction Trades Department, AFL-CIO, and serves as the research arm of the BCTD. For more information, visit www.cpwr.com.
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