Working Posture

WORKING POSTURE AND MUSCLES INJURIES

UPPER LIMB DISORDERS (ULD)

Upper limb disorders (ULDs) are arches, pains, tension, and disorders involving any part of the arm from fingers to shoulder, or the neck include problems with the soft tissues muscles, tendons and ligaments, along   with the circulatory and nerve supply to the limb and are often caused or made worse by work.

UPPER LIMBS

Upper limbs include fingers, hand, arm, shoulders, neck.

TISSUES

Soft tissues, muscles, ligaments, and tendons.

DISORDERS

Effect to tissue, change stiffness, weakness, pain, swelling etc.

RISK FACTORS ASSOCIATED WITH THEM

TASKS

REPETITIVE ACTIONS

• SHOULDER MOVEMENT > 2.5 PER MINUTES
• ELBOW BENDS                 > 10 PER MINUTES
• FOREARM/WRIST BENDS > 10 PER MINUTES
• TRINGGER FINGER         > 200 PER MINUTES
•  

WORK POSTURE :   Increased risk of injury when posture is awkward and / or fixed

FORCE

Force can affect various structures of the musculoskeletal system. Muscles effected are tendons/muscle tears and post exercise soreness. Effects on tendons include over stretching , fraying and shearing synovium. Effects on nerves include friction, stretching and squashing. Hand/wrist forces

Lower force  : 1 kg or less

Moderate  FORCE  : 1-4 kg

High Force  : more than 4 kg 

DURATION OF EXPOSURE

• REST BRAKES – short frequent breaks generally better than long in frequents breaks
• 36 minutes extra : 9 minutes break after every 51 minutes, most acceptable workplace which helps in :-
• Reduced worker discomfort for lower extremities
• Production rates improved in later hours of workday
•  

ENVIRONMENT

Working Environment

Cold

• Reduce blood flow to upper limbs
• Reduce grip
• Increase muscle activity

VIBRATION

• Liters sensation leading to “over Gripping”
• Increase muscle activity
• Increase in carpal tunnel syndrome ( vibration sensing part of brain)

LIGHTING

• Stopping to see and that effect in compromised posture
• Accommodating for glare
• Temperature wind

PSYCHOSOCIAL FACTORS

MACHINE PLACES WORK

Lack of control of pace and lack of participation in tasks design

SOCIAL ENVIRONMENT AT WORK

 Group pressure, negative, social interaction,  poor tasks feedback.

WORK SOCIAL AND OVERTIME

Shift work overtime fatigue work demands

INDIVIDUALS

INDIVIDUAL DIFFERENCES

• New employees
• Competence skill level
• Body size
• Vulnerable groups
• Health status and disability
• Individual attitudes/compliance

Workstation layout

• Achieve better working heights
• Reduce reach distances
• Use of deflectors on conveyors
• Good lighting
• Suitable tools for tasks e.g.  Tools with sufficient power/sharpness and accuracy 

ULD : ERGONOMICS GUIDELINE

ERGONOMIC :

Ergonomic is the relationship of worker with the workplace layout

• Production line speed
• Reduce speed
• Increase number of staff on the production line
• Improve preparation
• Deal with stopping the line
• Control/limit the focus being applied/weights being handled
• Deal with reluctance to stop line