There are four main ergonomic issues in industry related to weight limitation, posture, time, and metabolic energy. A recommended weight limit (RWL) equation is used to assess lifting tasks based on load weight and multiple factors like horizontal reach, frequency, and posture. Posture is important to avoid strain on the body and is assessed using the OWAS coding system which categorizes postures from normal to those requiring immediate correction. Software tools provide interfaces to calculate the RWL and analyze body posture.

1. Ergonomic Issue in Industry
• There are four ergonomics issue mostly found
are related to:
1. Weight limitation
2. Posture
3. Time
4. Metabolic energy

2. Recommended weight limit
• The recommended weight limit is used to
assess a lifting task and by given the
conditions.
• The equation for RWL is:
RWL = LC x HM x VM x DM x AM x FM x CM
LC, the load constant = 23 kg.

3. The other factors in the equation are:
• HM, the Horizontal Multiplier factor
• VM, the Vertical Multiplier factor
• DM, the Distance Multiplier factor
• FM, the Frequency Multiplier factor
• AM, the Asymmetric Multiplier factor
• CM, the Coupling Multiplier factor

4. Posture
• Working posture.
– The working posture and task should be designed
to avoid strain and damage to any part of the
body such as the tendons, muscles, ligaments, and
especially the back (Dahalan J, 2005)
– knowledge of the context and type of posture is
necessary in order to examine their associations
with health related outcomes (Taylor et al. 2005)

5. OWAS posture code definition
Body parts OWAS code Description of position
Back 1
2
3
4
Back straight
Back bent
Back Twisted
Back bent and twisted
Arm 1
2
3
Both arms below shoulder level
One arm at or above shoulder level
Both arms at or above shoulder level
Leg 1
2
3
4
5
6
7
Sitting
Standing on both straight legs
Standing on one straight legs
Standing or squatting on both feet, knees bent
Standing or squatting on one foot, knee bent
Kneeling on one or both knee
Walking or moving

6. Action category for each individual OWAS classified posture combination

7. The OWAS Action Categories for prevention
Action Category Explanation
1 Normal and natural postures with no harmful effect on the
musculoskeletal system – No action required
2 Posture with some harmful effect on the musculoskeletal
system – Corrective actions required in the near future
3 Postures have a harmful effect on the musculoskeletal system
– Correction actions should be done as soon as possible
4 The load caused by these postures has a very harmful effect
on the musculoskeletal system –Corrective actions for
improvement required immediately.

8. Flow Diagram for the Method of the Study

9. Flowchart of the Calculation RWL

10. USER INTERFACE (RWL)

11. Flowchart of the Calculation Body Posture

12. USER INTERFACE (Body Posture)