I recently facilitated a webinar entitled “Ergonomics for Manual Material Handling”. There were a lot of great questions; some of which we didn’t get a chance to answer during the session. For those questions, I thought that it would be helpful to post the answers up here on our blog.
What is “overexertion” and is OSHA record keeping required?
During the webinar, we mentioned the Liberty Mutual Workplace Safety Index. They define “overexertion” as “injuries caused from excessive lifting, pushing, pulling, holding, carrying or throwing”. They get the majority of their statistics from the Bureau of Labor Statistics who in turn gets their information from OSHA and Workers Compensation. The statistics I was quoting were based off of missing six or more days from work by total workers compensation costs.
The information is obtained from the OSHA 300 log which does have a category for both sprains and strains and overexertion. That being said, it is at the discretion of the reporters (ie. Companies) to decide which category they use to classify an injury. For instance, if someone is exerting force by pushing a cart, and they get a shoulder strain, they may enter that injury as a sprain/strain or due to overexertion. In a way the Liberty Mutual WSI is comparing apples and oranges because one is the “root cause” (overexertion) and the other is the type of injury (sprain/strain). Therefore, this data is only as accurate as those who are reporting it and it’s difficult as a reporter to ensure you’re choosing the right category.
What is the NIOSH SLI?
The National Institute of Occupational Safety and Health has recently released an article on a Lifting Index called the Sequential Lifting Index. The intent is to use this type of LI to assess jobs in which a worker moves between workstations where the characteristics vary between the elements. For instance, moving between entirely different workstations and lifting varying loads for various durations and frequencies. But not only that, the SLI investigate the order in which the worker carries out the tasks and the impact that can have.
There is an article that will provide additional information if this is something that you feel your company would benefit from using. However, if the tasks are relatively similar, I would recommend using the worst case scenario or the cumulative lifting index (CLI). It may not be worth the effort to calculate the SLI if the tasks are similar.
You can find the article by clicking here.
Who were the participants in the NIOSH LE studies and the Liberty Mutual studies to come up with this data?
First of all, these studies have been expanding over the years and more and more data keeps getting entered to ensure the most accurate information is being used so the populations considered have been getting better and more representative of who is actually performing these types of tasks.
Initially, the studies started, as most studies do, with student participants who are readily available on campus. Since those initial data collections in the 80’s, the researchers have expanded their participant pool to include industrial workers. In order to get ethics approval, the participants must be considered “healthy” and “working age”. Therefore, the range will be anywhere from 25 to 45 year olds, but the population studied would not be representative of the “aging population”. If you have an older workforce, my suggestion would be to consider designing for 90% of females as opposed to 75% of females to be more conservative with your guidelines and accommodate more individuals.