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Nelson & Associates :: Manual Lifting & Materials Handling :: 3D SSPP

Analysis of Manual Lifting and Carrying Task Using
3D Static Strength Prediction Program™


The 3D Static Strength Prediction Program™ (3D SSPP) is based on over 30+ years of research at the Center for Ergonomics at the University of Michigan regarding the biomechanical and static strength capabilities of the worker in relation to the physical demands of the work environment. Based on input data including posture information, force parameters, and human anthropometry, the software provides output results including the percentage of men and women who have the strength to perform the task, spinal compression forces, and data comparisons to NIOSH guidelines.

Torso muscle moment arms and muscle orientation data for the L4/L5 lumbar level have been studied more extensively that at any other lumber level. Thus, the 3D Static Strength Prediction Program reports its findings relative to the strain on L4/L5, the disc immediately above L5/S1 (the disc of focus regarding the NIOSH Revised Equation). However, in reality, this difference must be considered unremarkable as both L4/L5 and L5/S1 possess a common disc structure and damage level associated with 770 pounds compression force as the lower limit of prime significance (being the upper limit of intrinsic safety, above which the risk of damage requires that action be taken to redesign the lifting task), and 1430 pounds compression force, being the upper limit of tolerance (beyond which should be viewed as extremely hazardous to nearly all industrial workers, even to those who are healthy and accustomed to physical labor). The 3D Static Strength Prediction Program refers to these two critical disc compression levels as the Strength Design Limit (SDL), and the Strength Upper Limit (SUL).

For more information on this dynamic prediction program, go to the Center for Ergonomics Website of the University of Michigan College of Engineering using the following links:

From the 3DSSPP website:

"3D SSPP software predicts static strength requirements for tasks such as lifts, presses, pushes, and pulls. The program provides an approximate job simulation that includes posture data, force parameters and male/ female anthropometry. Output includes the percentage of men and women who have the strength to perform the described job, spinal compression forces, and data comparisons to NIOSH guidelines. The user can analyze torso twists and bends and make complex hand force entries. Analysis is aided by an automatic posture generation feature and three dimensional human graphic illustrations."

© Nelson & Associates, 2010