Explain how TWO biomechanical principles can be applied to improve movement efficiency for a person using a prosthetic leg. (4 marks)
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Sample Answer – ANY 2 of the following:
Centre of gravity positioning:
- Prosthetic alignment adjusts centre of gravity to compensate for missing mass. This occurs because proper positioning balances weight.
- As a result, less muscular effort maintains balance. Therefore, users walk longer distances without fatigue.
Lever principles:
- The prosthetic foot acts as a lever during push-off phase.
- This works by creating mechanical advantage through optimal positioning.
- Consequently, force transfer efficiency increases through the prosthetic, enabling reduced energy for forward progression.
Force absorption:
- Carbon fibre springs absorb impact forces during heel strike.
- This happens when material compresses on ground contact.
- Following this, energy storage and return minimises jarring so that comfortable movement continues over extended periods.
Momentum conservation:
- Lightweight prosthetic components maintain momentum between steps more effectively than heavier designs.
- The reason for this is reduced mass requires less acceleration muscle force.
- Subsequently, the swing phase uses less muscle effort, resulting in significantly improved walking endurance.
Show Worked Solution
Sample Answer – ANY 2 of the following:
Centre of gravity positioning:
- Prosthetic alignment adjusts centre of gravity to compensate for missing mass. This occurs because proper positioning balances weight.
- As a result, less muscular effort maintains balance. Therefore, users walk longer distances without fatigue.
Lever principles:
- The prosthetic foot acts as a lever during push-off phase.
- This works by creating mechanical advantage through optimal positioning.
- Consequently, force transfer efficiency increases through the prosthetic, enabling reduced energy for forward progression.
Force absorption:
- Carbon fibre springs absorb impact forces during heel strike.
- This happens when material compresses on ground contact.
- Following this, energy storage and return minimises jarring so that comfortable movement continues over extended periods.
Momentum conservation:
- Lightweight prosthetic components maintain momentum between steps more effectively than heavier designs.
- The reason for this is reduced mass requires less acceleration muscle force.
- Subsequently, the swing phase uses less muscle effort, resulting in significantly improved walking endurance.