1. UNIT 4 Muscle: the ultimate force generator in the body
Duration
4th week / 3 contact hrs.
5th week / 3 contact hrs.
topics
Types of muscle contraction (Isometric, Isotonic: Eccentric & Concentric)
Role of muscles (agonist, antagonist, stabilizers, synergists, neutralizers)
Muscle skeletal stabiliser generating an appropriate amount of force at a given length
Muscle morphology: shape and structure
Muscle architecture

2. Types of muscle contraction
Concentric contraction
Eccentric contraction
Isotonic contraction
Isokinetic contraction
Isoinertial contraction
Isometric contraction.

3. Concentric contraction
It is the type of muscle contraction in which the muscle length shortens.

4. Eccentric contraction
It is the type of muscle contraction in which the muscle elongates.

5. Isotonic contraction
It is the type of muscle contraction in which the muscle tone remains constant.

6. Isokinetic contraction
It is the type of muscle contraction in which the angular velocity of the segment remains constant.
Variable resistance
Possible with dynamometers.

7. Isoinertial contraction
It is the type of muscle contraction in which the resistance to the muscle remains constant.

8. Isometric contraction
It is the type of muscle contraction in which the muscle length remains same.

9. Functional Role of the muscles
Five different roles
Agonist.
Antagonist.
Synergist.
Fixators or stabilizer.
Neutralizers.

10. Muscle which acts as a primary mover of the body segment.
Agonist
Muscle which acts as a primary mover of the body segment.
Example: elbow flexion by brachialis.

11. Muscle which act opposite to the agonist.
Antagonist
Muscle which act opposite to the agonist.
Example: Relaxation of triceps when biceps contract

12. Synergist
Muscle which assist the action of primary mover or agonist.
Contraction of rectus femoris during flexion of hip joint by hip flexors.

13. stabilizers or fixators
Muscle which stabilizes the proximal segment of the joint to be moved.
Example: stabilization of shoulder joint during elbow flexion

14. neutralizers Prevents unwanted movement during the desired movement.
Examples: the biceps can flex the elbow and supinate the forearm. If only elbow flexion is wanted, the supination component must be ruled out. Therefore, the pronator teres, which pronates the forearm, would contract to counteract the supination component of the biceps, and only elbow flexion would occur.
Neutralizers act to cancel out an unwanted movement

15. Muscle skeletal stabiliser generating an appropriate amount of force at a given length
Classification of muscle depending upon the number of joints they cross.
One joint muscle. Eg: Deltoid
Two joint muscle. Eg: rectus femoris
Multiple joint muscle. Eg: Flexor digitorum

16. Muscle insufficiency with length
Passive insufficiency
Active insufficiency

17. Active insufficiency
Insufficiency due to exhaustion of muscle to contract further.
Happens in multiple joint muscles.
MUSCLE CANNOT COMPLETE THE ROM AS THE MUSCLE HAS UNDERGONE FULL CONTRACTION.
EXAMPLE: ALL MULTI-JOINT MUSCLES.

18. Passive insufficiency
Insufficiency due to passive tension in the opposite group of muscle.
Happens in multiple joint muscles.