MNSR 6 - Skeletal Lever Systems Flashcards Preview

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Flashcards in MNSR 6 - Skeletal Lever Systems Deck (12)
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1

Explain what happens to muscle with age.

As a person ages, there's a gradual decrease in the number of muscle fibers, muscle converts to intramuscular fat, and muscle and bone lose their elasticity which hinders joint movement.

2

What is maximum tension dependent on?

Maximum tension is dependent on 2 factors:
1. cross-sectional area of muscle at its widest point
2. Length of the muscle (max force is generated when the muscle is stimulated from its relaxed state)

3

What are the two types of muscle?

There are two types of muscle:
1. Fusiform muscle: fibers run parallel to the length of the muscle.
2. Pennate muscle: fibers insert into a central tendon, are at an angle to the force-generating axis & generate more force than the fusiform muscles BUT smaller range of motion. There are three types:
- unipennate: forearm
- bipennate: thigh
- multipennate: shoulder joint

4

Differentiate between Agonist & Antagonist Muscles.

1. Agonist/Primer mover/Normal: carry out the desired movement
2. Antagonist muscles: assist agonist in controlled relaxation

5

What can a lever do?

A lever can be used to magnify a force or change its direction.

6

Define Mechanical Advantage.

MA = Fi/Fa
Fa < Fi = efficient --> mechanical advantage
Fa > Fi = inefficient --> mechanical disadvantage

7

Discuss Class I Levers.

Fi fulcrum Fa
Fa < Fi OR Fa > Fi OR MA = 1 (EFFICIENT OR INEFFICIENT)
Head lift

8

Discuss Class II Levers.

Fa Fi Fulcrum
Fa < Fi OR MA > 1 (EFFICIENT)
Calf Extension

9

Discuss Class III Levers

Fi Fa Fulcrum
Fa > Fi OR MA < 1 (INEFFICIENT)
Bicep Curl

10

Define Torque.

Torque is a force which causes rotational motion about a fixed point. Toure = Force x Perpendicular Distance

11

Under what 2 conditions does equilibrium occur?

1. Net force = zero
2. Net torque = zero

12

State the formula for Equilibrium and Torque.

Sum of Clockwise torque = Sum of Anti-clockwise torque