Ergonomics

Question 1

greatest biomechanics stressors and largest moments during lifting occur in lumbar spine: specifically

Answer 1

L5-S1

Question 2

Sitting Position transfers body weight to supporting areas

Answer 2

seat pan through ischial tuberosities

backrest through soft tissues

armrest through forearms

floor

Question 3

Sitting Posture Controls

Answer 3

• pelvis rotates posterior and lumbar spine flattens when transitioning from standing to unsupported sitting
• Knee and hip angles control spinal posture during sitting

Question 4

Lumbar Disc Pressure during Sitting

Answer 4

• Compression forces measured at L3:
  
  • 35% higher F in unsupported sitting than standing
• use of lumbar support decreases disc pressure
• **BACKWARD INCLINATION OF THE BACKREST FROM 90-110 DEG RESULTS IN DECREASED LUMBAR DISC PRESSURE**
• decreased disc pressure w/use of armrests

Question 5

Chair Dimensions for Seated Work

Answer 5

• knee flexion angle:
  
  • 90 deg w/ popliteal fold about 2-3 cm above seat surface
• chair length/depth
  
  • seat pan should provide 10 cm clearance from popliteal fossa
• Seat pan slope
  
  • backward slope of 5 deg is suggest for normal upright sitting

Question 6

Common Work Related Musculoskeletal Disorders

(WRMSD) Upper Extremity

Answer 6

• Carpal Tunnel
• Tendinitis
• Tenosynovitis
• Ganglion Cysts
• Bursitis
• Myositis
• Synovitis
• Fibromyalgia
• Osteoarthritis
• Raynaud’s Syndrome
• Complex Regional Pain Syndrome CPRS