Slide 1Slide 2Workplace Design (Ch. 10) Biomechanical factorsMusculoskeletal Injury: 1st stage – fatigue (static)Slide 5Slide 6Slide 7Slide 8Shoulder Joint and MusclesShoulder Joint ProblemsSlide 11Arm Abduction = ↑ Muscle ActivityArm Abduction = ↓ Shoulder StrengthArm Abduction = ↑ Muscle FatigueArm Abduction = ↑ Energy Expenditure & ↓ PerformanceShoulder Flexion ↑ Height = ↓ Endurance Time↑ Shoulder Flexion = ↓ Endurance Time (Elbow unsupported)↑ Shoulder Flexion = ↓ Endurance Time (Elbow supported)Forearm Support = ↓ Fatigue & ↑ Working TimeForearm Rotation Strength↑ Neck Tilt = ↑ Muscle Load↑ Neck Tilt = ↑Muscle Fatigue↑ Back Tilt = ↓ Endurance TimeSlide 24IE 5531IE 553 Engineering of Human WorkDr. Andris FreivaldsClass #19IE 5532IE 553 Engineering of Human WorkDr. Andris FreivaldsClass #19IE 5533Workplace Design (Ch. 10)Biomechanical factorsMusculoskeletal Injury:1st stage – fatigue (static)T(sec)= 1236.5 - 72.5 (Rohmert, 1960) (%MVC-15)0.618IE 5534Musculoskeletal Injury:1st stage – fatigue (static)Muscle a bA - biceps 61.45 16.99B - biceps 67.33 22.22C - back 71.23 20.41D – body pull 79.05 23.81E – hand grip 62.44 22.22F – body torque 58.61 23.26G - pronation 53.56 20.28H – arm pull 53.81 21.19I – arm pull 60.08 19.88J – sum of 5 60.27 22.32%MVC = a – b ln T(van Dieën, Vrielink, 1994)IE 55351st stage – fatigue(static work/rest cycling)(Lee, 1979)IE 55362nd stage – Pain (Caldwell and Smith, 1966)IE 55373rd stage – Inflammation, chronic pain, injury, functional disabilityIE 5538Shoulder MusculatureIE 5539Shoulder Joint and MusclesIE 55310Shoulder Joint ProblemsIE 55311Arm Abduction =Large MomentsIE 55312Arm Abduction = ↑ Muscle ActivityIE 55313Arm Abduction = ↓ Shoulder StrengthIE 55314Arm Abduction = ↑ Muscle FatigueIE 55315Arm Abduction = ↑ Energy Expenditure & ↓ PerformanceIE 55316Shoulder Flexion↑ Height = ↓ Endurance TimeTime (min) to reach fatigueIE 55317↑ Shoulder Flexion = ↓ Endurance Time (Elbow unsupported)IE 55318↑ Shoulder Flexion = ↓ Endurance Time (Elbow supported)IE 55319Forearm Support = ↓ Fatigue & ↑ Working TimeIE 55320Forearm Rotation Strength Best when elbow flexedPoor when elbow extendedIE 55321↑ Neck Tilt = ↑ Muscle LoadIE 55322↑ Neck Tilt = ↑Muscle FatigueIE 55323↑ Back Tilt = ↓ Endurance TimeEndurance Time(min)IE 55324Postural Effects Due to
View Full Document
Unlocking...