1. THE EFFECT OF BAG MASS ON THE SHOULDER AND HIP POSTURAL ANGLES OF 4A2012 STUDENTS

2. TABLE OF CONTENTS Abstract Problems and Hypotheses
Background of the Study
Variables
Methodology
Data Presentation
Analysis of Data
Conclusion
Closure
Sources 

3. ABSTRACT Problem: muscle pain due to heavy bags
Project: postural analysis- shoulder-shoulder and shoulder-hip angles
Results: angles increase as bag mass increases
Note: greater change in angles in lighter subjects
Effect: inform students of ideal load weight

4. PROBLEMS and HYPOTHESES
1. How does bag mass affect the shoulder-shoulder angle?
If the mass increases, so will the angle.
2. How does bag mass affect the shoulder-hip angle?
3. How does the subject's mass affect the angles? 
If the mass increases, angles will decrease.

5. BACKGROUND Shoulder-supported bags are commonly used by students
Carrying beyond safe load-bearing (5-10% of body mass) prevalent in adolescent students 
Bags may induce postural deficiencies
Study aims to provide information for musculoskeletal well-being of bag-users

6. VARIABLES Independent: Total bag mass, Weight of subject
Dependent: Shoulder-shoulder angle, Shoulder-hip angle
Constant: Type of bag, Type of weight, Type of postural analysis grid, Position of feet

7. Neutral position with marked joints
METHODOLOGY
The subject was weighed.
The postural analysis grid (PAG) was posted.
Control setup: subject stood in a neutral position with no bag.
Shoulder-shoulder and hip-shoulder angles were measured using arctangent functions.
Neutral position with marked joints

8. Experimental setup (shoulder-hip)
METHODOLOGY
Experimental setup: subject stood in a neutral position with a bag weighing 3 kg, 6 kg and 9 kg.
The shoulder-shoulder and hip-shoulder angles were measured using arctangent functions.
 Twenty test subjects were taken.
Experimental setup (shoulder-hip)

9. DATA PRESENTATION
The graph shows that as the weight of the bag increases, so does the shoulder-shoulder angle.

10. DATA PRESENTATION
The graph shows that as the weight of the bag increases, so does the shoulder-hip angle.

11. DATA PRESENTATION
The graph shows that as the weight of the subject increases, the shoulder-shoulder angle decreases.

12. DATA PRESENTATION
The graph shows that as the weight of the subject increases, the shoulder-hip angle decreases.

13. ANALYSIS As mass increases, so does the weight.
The shoulder muscle and bone shift downward and forward.
This compensates for a change in the center of gravity.
Equilibrium is achieved.
Law of Acceleration (F=ma)

14. CONCLUSION Weight matters in postural differences Further research:
- Bag: Heavier bag, greater change
- Body mass: Heavier subject, less change
Further research:
- More precise measuring instruments for better data quality
- Observe changes in muscle activity as well

15. CLOSURE Heavy backpacks can ruin a student’s body.
What are you going to do about it?