MNSR 9 - Mechanical Balance and Stability

Question 1

Define Centre of Gravity.

Answer 1

Centre of gravity is the single point where all the mass is imagined to be. For symmetrical objects, the CoG is considered to be at the object’s center. For unsymmetrical objects, the CoG can be off-center and located outside of the body.

Question 2

Define Stability.

Answer 2

An object is stable when the center of gravity lies above the base of support area.

Question 3

State the relation between CoG & Stability.

Answer 3

The lower the CoG, the larger the angle at which the object’s CoG lies within the base of support area, therefore the greater the stability.

Question 4

Define Scoliosis.

Answer 4

Scoliosis is the curvature of the spine, usually in an S or C shape.

Question 5

Relate pregnancy to CoG.

Answer 5

The CoG of pregnant women is shifted forward, which creates large torques and excess stress on the spine and lower back muscles. Additionally, this strain on the back muscles and spine creates a higher CoG, which decreases stability.

Question 6

What happens to an amputee who lost their left leg.

Answer 6

1. Shift in center of gravity
2. Small base of support
3. Hyperextended knee
4. External rotation of left knee
5. Retraction and elevation of right pelvic girdle
6. Depression of right shoulder girdle