Muscle work

Introduction and overview of types of muscle work and muscle contraction in human body.

1. Dr. Vivek H. Ramanand i (PT) M.P.T. ( Neuro ), Ph. D. Scholar

2. Content Definition of Muscle work Types of muscle work Static work Dynamic work Types of Muscle Work_DR . VIVEK RAMANANDI 2

3. Definition “A muscle fiber generates tension when properly stimulated, by the nervous system or by electrical impulses. This physiological process is called muscle contraction .” Types of Muscle Work_DR. VIVEK RAMANANDI 3

4. Types of Muscle Work Types of Muscle Work_DR. VIVEK RAMANANDI 4

5. Types of Muscle Work Types of Muscle Work_DR. VIVEK RAMANANDI 5

6. Types of Muscle Work ( cont …) Types of Muscle Work_DR. VIVEK RAMANANDI 6

7. Static Muscle Work Types of Muscle Work_DR. VIVEK RAMANANDI 7

8. Isometric Muscle Contraction When a muscle contracts, producing force without changing the length of muscle. Muscles are not always directly involved in the production of joint movements. They may exercise either a restraining or a holding action Types of Muscle Work_DR. VIVEK RAMANANDI 8

9. Isometric Muscle Contraction (cont…) Types of Muscle Work_DR. VIVEK RAMANANDI 9

10. Dynamic work Types of Muscle Work_DR. VIVEK RAMANANDI 10

11. 1. Isotonic Muscle Contraction This term is commonly used to define muscle contraction in which the tension is constant throughout a range of motion . Two types: Types of Muscle Work_DR. VIVEK RAMANANDI 11

12. Concentric Muscle Contraction When there is joint movement, the muscles shorten , and the muscle attachments move toward each other. When muscles develop sufficient tension to overcome the resistance of the body segment, the muscles shorten and cause joint movement. Positive work is being done by the muscle because the joint moves through a ROM. Types of Muscle Work_DR. VIVEK RAMANANDI 12

13. Concentric Muscle Contraction Types of Muscle Work_DR. VIVEK RAMANANDI 13

14. Concentric Muscle Contraction A ction of the quadriceps in extending the knee when ascending the stairs . Types of Muscle Work_DR. VIVEK RAMANANDI 14

15. Eccentric Muscle Contraction When there is joint motion, the muscle appears to lengthen ; that is, the muscle attachments separates. When a muscle cannot develop sufficient tension & is overcome by the external load, it progressively lengthens instead of shortening . Negative work because the work is done on the muscle rather than by the muscle Types of Muscle Work_DR. VIVEK RAMANANDI 15

16. Eccentric Muscle Contraction Types of Muscle Work_DR. VIVEK RAMANANDI 16

17. Eccentric Muscle Contraction Q uadriceps works eccentrically to decelerate flexion of the knee during descending the stairs. Types of Muscle Work_DR. VIVEK RAMANANDI 17

18. 2. Isokinetic Muscle Work With an isokinetic contraction, resistance to the part varies, but the velocity, or speed stays constant, hence the velocity of shortening or lengthening of the muscle is constant. It can be done only with special equipment. Types of Muscle Work_DR. VIVEK RAMANANDI 18

19. 3. Isoinertial Muscle Work The resistance against which the muscle must contract remains constant . Isoinertial contraction occurs when a constant external load is lifted. Types of Muscle Work_DR. VIVEK RAMANANDI 19

20. 3. Isoinertial Muscle Work (cont …) If the moment (torque) produced by the muscle is equal to or less than the resistance to be overcome, the muscle length remains unchanged and the muscle contracts isometrically . If the moment is greater than the resistance, the muscle shortens (contracts concentrically) and causes acceleration of the body part. Types of Muscle Work_DR. VIVEK RAMANANDI 20

21. References Pamela K. Levangie , Cynthia C. Norkin . Joint structure and function. Fourth edition. Margareta Nordin , Victor H. Frankel. Basic Biomechanics of the Musculoskeletal system. Thied edition. Types of Muscle Work_DR. VIVEK RAMANANDI 21

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