1. 11. Biomechanics of Work

2. THE MUSCULOSKELETAL SYSTEM

3. Bones and Connective Tissues

5. Synovial Joint
Fibrous Joint
Cartilaginous Joint

6. Muscles

7. Muscles

8. BIOMECHANICAL MODELS

9. Single-Segment Planar Static Model
(Q) Suppose a person is holding a load of 20-kg mass with hands in front of his body and his forearm are horizontal. The load is equally balanced the two hands
W = mg = 20kg*9.8m/sec = 196N
Won-each-hand = 98N
∑ Felbow = 0
- 16N – 98N + Relbow = 0
Relbow = 114N
∑ Melbow = 0
- 16N(0.18m) – 98N(0.36m) + Melbow = 0
Melbow = 38.16N-m
shoulder
30°
HW:
What are the reactive force and moment at shoulder?
BW = 78Kg
Upper arm = 0.028BW
distance from shoulder to elbow = 33cm
center of mass = 15 cm from the shoulder
elbow

10. LOW-BACK PROBLEM

11. Low-Back Biomechanics of Lifting
Clockwise rotational moment:
Mload-to-torso (L5/S1) = Wload*h + Wtorso*b
Counterclockwise rotational moment:
Mback-muscle = Fback-muscle * 5(N-cm)
∑ ML5/S1 = 0
Fmuscle * 5 = Wload*h + Wtorso*b
Fmuscle = Wload*h/5 + Wtorso*b/5
If h=40cm and b=20cm then
Fmuscle = 8*Wload + 4*Wtorso
Torso weight = 350N, Load = 300N (about 30kg) then
Fmuscle = 3,800N
Normal range of strength capability of the erector spinal muscle is 2,200 to 5,500N
Compression force on L5/S1 (ignoring the abdominal force, fa)
∑ F L5/S1 = 0
Fcompression = Wload*cosα + Wtorso*cosα + Fmuscle
Suppose α = 55°, torso weight 350N, load = 450N
Fcompression = 450*cos 55° + 350*cos 55°
= = 5458N

12. Seated Work and Chair Design

13. Seated Work and Chair Design

14. 아우디 생산직 파트에 보급된 제품.
가볍고(무게 2.5kg 정도) 어디서나 앉아 쉴 수 있도록 만들어졌음.

15. UPPER-EXTREMITY CUMULATIVE TRAUMA DISORDERS

16. Common Forms of CTD
Tendon-Related CTD
Neuritis
Ischemia
Bursitis

18. Causes and Prevention of CTDs
Common Forms of CTD
CTDs of the Finger
CTDs of the Hand and Wrist
CTDs at the Elbow
CTDs at the Shoulder
Causes and Prevention of CTDs

21. Hand-Tool Design Do not bend the wrist.
Shape tool handles to assist grip.

22. Hand-Tool Design Provide adequate grip span.
Provide finger and gloves clearances