"The further the your hands are away from the L5/S1 during manual lifting the more strenuous the lift."
In the 1980's the University of Michigan was commissioned by the NASA space program to develop a computer model that would calculate stress placed on the human body during manual lifting.
The Center for Ergonomics at U of M was also working on the NIOSH Guide for Manual lifting at this time.
The researchers determined one of the major points of stress during lifting was the lower back L5/S1.
Liberty Mutual Insurance Company reported that 80% of the one billion dollars in workers compensation benefits spent in a year were related to low back injuries on the job.
Isometric strength testing studies were performed by the researchers at the Center for Ergonomics for United Airlines, Alcoa Aluminum and Firestone Tire and Rubber. All the material handling jobs for these companies were analyzed and given a job description. From these job descriptions, six critical lifts were identified. And at least one of these lifts could be found in each job description.
These six lifting positions can now be found in the NIOSH lifting manual.
Today these lifts are used in pre-employment testing. The idea is to place the stronger workers on the more strenuous jobs.
The present isometric testing system sold by Arcon is an updated version of the system used in these studies.
The reason the researchers used isometric strength testing over other methods of strength testing was for the following reasons:
Safe to Administer.
Reliable and repeatable.
Related to job requirements.
Predictive of risk of future injury.
A list of some companies who purcahsed our isometric strength system are as follows:
United Airlines - Iowa Beef Packing - General Tire &Rubber - Busch Entertainment -
Exxon Mobil -Cargill - Western Electric - ALDI, Inc. - Michigan Consolidated Gas -
US Army - US Department of Navy -Marathon Oil company - Wierton Steel -
Supervalue Stores - Phoenix Fire Department -State Electrical Commission Australia -
Ohio Industrial Commission - General Motors Institute -Seaboard System Railroad -
Kerr-McGee Coal Corporation - NIOSH - Department of Health Australia -