Assignment Instructions and Questions
In module 2 you learned how to use the ruler method to measure body dimension.
In this module you are going to use the ruler method as well as an excel sheet to calculate the lumbar spine compression force for two lifting activities.
The video file named “compression force calculation sheet” posted under materials file section of this order demonstrates how you can use the excel sheet to calculate the spine compression force.
Part A:
- Watch the video.
- Did you learn the whole process?
- Now Watch the 4 videos below:
- The lifting positions start from standing (let’s call it A), bending to lift the load (B), touching to lift the load (C), Standing to lift the load (D), and dropping the load (E), and standing with no load in hand (F).
- Download the two squat and stoop images (this is provided in the material file section of this order as squat and stoop posture images respectively) as example that shows A-E conditions for another lifting case. This example is used show you how the next excel file is used to estimate spinal loading.
- Download the excel file, (this is provided in the material file section of this order). Using the instruction in the video in line 1, learn how the spine compression force is calculated and graphed.
- Now, use the ruler method to find the distance of the load from the body for conditions A to F in line 4. Determine the trunk angle using a protractor. Then, for each condition/posture enter the values in to the spread sheet as described in the video line 1. Once you find the ratio of your body height by the ruler, you can use this ratio to determine the load distances on the spine in the image. Remember that the downloaded images in line 5 is just for demonstration and used as an example (how to find the hand distance from the spine horizontally). The images are not used for calculation.
- The load weight is always 20Kg when it is in hands and obviously 0 Kg when is on the floor.
- At this point you should have been able to find the compression force for all 4 videos in line 3 and you have been able to make the graph that shows the lifting trend from condition A to condition F for each video.
- Compare the compression force for all conditions and discuss your results. For example, how is the spine compression force of the stoop versus the other 3. How do you compare squat with centre of gravity?
- Your report for part A should include: an introduction about stoop and squat lifting, a methodology that explains how you determined the spine compression force, results (only the excel graph and the trend from A-F in a paragraph), conclusion and discussion. Please discuss the knees compression force even though it is not part of this study.
Part B:
What you did in Part A was only comparison of the compression force without considering the time and frequency of the activity, coupling factors, etc. Let’s compare the two postures this time for the following conditions using NIOSH equation:
- Load weight:20kg
- Duration: 5 hrs
- Lifting frequency: 4 lifts/min
- Good coupling
- Symmetrical lift
- Download NIOSH Job analysis form (this is provided in the material file section of this order as Job Analysis Worksheet).
- Insert the variables found above in to the form to determine RWL and LI in the Origin (condition C) and the Destination (condition E) of stoop and squat postures. Insert the forms (one for squat and one for stoop) into the report (after the discussion of the previous report).
- In one paragraph (after the two forms), compare the RWLs for both conditions. Which variable is affecting the RWL the most?
Part C:
Make a video of yourself demonstrating a correct AND incorrect lifting from the ground to your elbow height Similar to the video in part 1. No talking, no introduction, no comparison, no training, very short and comfortable lifting. The size, weight of the load is not important. Just a simple, easy, smooth lift that convinces your ergonomist friend that you know what you are talking about when it comes to proper lifting. The video is worth of 30%. The correct lifting must apply less load to the spine and the knees than the incorrect lifting. I will use the method you utilized above to compare your correct/incorrect lifting methods. If the correct lifting method applies equal or more spinal loading, you will receive zero out of 30%.
What you submit is: one report and one/two very very short video!
