Wrist Extension and Keyboard Posture
Extended wrist angles compress the carpal tunnel during typing.
- 0-5°: Neutral angle (lowest tunnel pressure)
- >30°: High-risk angle (marked pressure rise)
- Ulnar/radial: Deviation risk (adds to extension load)
- Elbow level: Keyboard height (key neutral factor)
Posture and tunnel pressure
Placeholder: wrist extension raises intracarpal pressure during keyboard use.
Repetitive Motion Accumulation
Repeated flexion-extension cycles accumulate tendon and nerve stress.
- ~10,000: Keystrokes/hr (typical data entry)
- Cumulative: Cycle risk (microtrauma builds)
- Microbreaks: Recovery need (every 20-30 min)
- >4 h/day: Task duration (threshold of concern)
Repetition and cumulative load
Placeholder: repetitive motion accumulates strain across the shift.
Vibration Exposure Factor
Hand-arm vibration from power tools compounds nerve compression risk.
- 2.5 m/s²: Exposure limit (daily action value)
- Power tools: Tool type (grinders, drills)
- Synergistic: Added risk (with posture/repetition)
- Anti-vibration gloves: Damping (partial mitigation)
Vibration and nerve stress
Placeholder: vibration exposure adds to median nerve irritation.
Workstation Setup Optimization
Proper desk and keyboard configuration restores neutral wrist posture.
- Adjustable: Keyboard tray (sets elbow angle)
- Padded: Wrist rest (reduces extension)
- Eye level: Monitor height (reduces compensations)
- Armrests: Chair support (shares load)
Optimizing the workstation
Placeholder: ergonomic setup lowers sustained wrist extension.
Cumulative Risk Over the Workday
Risk factors compound hour by hour across a full shift.
- 8 h: Shift length (standard workday)
- Rising: Risk curve (without breaks)
- Resets partial load: Break effect (per recovery period)
- CTS risk: Long-term outcome (from sustained exposure)
Daily accumulation of risk
Placeholder: cumulative exposure across the workday drives CTS risk.
Placeholder: reducing angle and hours lowers cumulative CTS risk.