Ergonomics

Ergonomics Essentials - Body & Work Harmony

• Definition: Science of fitting the job to the worker, enhancing well-being and system performance.
• Aims: Optimize: efficiency, safety, comfort, health. Prevent: musculoskeletal disorders (MSDs).
• Components:
  • Physical: Body's interaction with tasks (posture, force, repetition).
  • Cognitive: Mental processes (perception, memory, workload).
  • Organizational: Work system design (job structure, teamwork).
• Key Principles: Maintain neutral postures; reduce excessive force & motions; keep items in easy reach; work at proper heights; minimize fatigue & static load; encourage movement; comfortable environment.

⭐ The primary aim of ergonomics is to fit the job to the worker, not the worker to the job, to enhance efficiency and well-being.

MSD Culprits - Strain & Pain Triggers

Ergonomic risk factors cause WRMSDs. 📌 Mnemonic: FORCE (Force, Overuse/Repetition, Reach/Posture, Contact Stress, Environment/Vibration). Also: Duration, Temperature.

Ergonomic Risk Factors & Associated WRMSDs:

• CTS: Median nerve compression; pain/numbness lateral 3.5 fingers.
• LBP: Lumbar pain; from poor posture/lifting.
• Neck Pain: Cervical pain; often from forward head flexion.

⭐ Carpal Tunnel Syndrome is commonly associated with repetitive wrist movements and is the most frequently reported upper limb WRMSD.

Ergo Fixes - Smart Work Solutions

• Ergonomic Assessment Methods:
  • Observational: Visual tools (RULA, REBA, QEC, OWAS).
  • Direct Measurement: Instrumental (Goniometry, EMG).
  • Checklists: Standardized (e.g., OSHA).
• NIOSH Lifting Equation:
  • Assesses low-back injury risk from manual lifting.
  • $LI = L / (RWL)$ (L=Load Weight, RWL=Recommended Weight Limit).
  • $RWL = LC \times HM \times VM \times DM \times AM \times FM \times CM$ (LC=Load Constant; HM, VM etc. are multipliers).
  • $LI > \textbf{1.0}$ indicates increased risk.
• Hierarchy of Controls: Prioritized approach for ergonomic risk mitigation.
  • 1. Elimination: Physically remove hazard.
  • 2. Substitution: Replace hazard.
  • 3. Engineering Controls: Isolate from hazard (e.g., workstation redesign, lifting aids).
  • 4. Administrative Controls: Change work practices (e.g., job rotation, training, rest breaks).
  • 5. PPE: Protect worker (e.g., anti-vibration gloves - limited effectiveness).

  ⭐ Engineering controls, such as redesigning tools or workstations, are the most effective and preferred methods for mitigating ergonomic hazards.

  • Control Application Flowchart:

VDT Vision - Screen Smart Setup

• Workstation Ergonomics

  • Monitor: Top at/below eye level, 50-70 cm away, 15-20° downward gaze.
  • Posture: Neutral spine; elbows, hips, knees ~90°; wrists straight.
  • Input: Close, neutral wrists.
  • Chair: Adjustable, lumbar support.
  • Lighting: Glare-free.

• Health & Prevention

  • CVS (Eye Strain): Use 📌 20-20-20 rule (every 20 min, 20 ft view, 20 sec).
  • MSDs (Pain): Good posture, breaks.

⭐ For VDT users, the top of the screen should be at or slightly below eye level, and the viewing distance should be 50-70 cm (arm's length). The 20-20-20 rule helps prevent Computer Vision Syndrome.

High‑Yield Points - ⚡ Biggest Takeaways

• Ergonomics: Fitting the job to the worker to boost safety and productivity.
• Prevents Musculoskeletal Disorders (MSDs) like Carpal Tunnel Syndrome & Low Back Pain.
• Focuses on neutral postures, reduced forceful exertions, and minimal repetition.
• Anthropometry guides design of ergonomic workstations and tools.
• Interventions: Job rotation, tool redesign, workstation adjustment, and training.
• Key risk factors: Awkward postures, static loads, vibration, repetitive tasks.