1 / 30

Basic Biomechanical Factors and Concepts

Basic Biomechanical Factors and Concepts. Anatomy and Physiology of Human Movement 420:050. Outline. Levers Anatomical Levers. Outline. Levers Anatomical Levers. Introduction to Levers. Lever: Simple machine that operates according to principle of torques

winthrop
Télécharger la présentation

Basic Biomechanical Factors and Concepts

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Basic Biomechanical Factors and Concepts Anatomy and Physiology of Human Movement 420:050

  2. Outline • Levers • Anatomical Levers

  3. Outline • Levers • Anatomical Levers

  4. Introduction to Levers • Lever: Simple machine that operates according to principle of torques • Torque: The turning effect of a force T = Fd

  5. d How can you change torque? 1. Change F 2. Change d 3. Change direction of F F

  6. d Optimal direction = 90 degrees F

  7. Function of Levers • Two functions: 1. Force 2. Speed/ROM

  8. Function of Levers • Force • Examples? • Common traits? • Rigid bar • Fixed point • Lever movement vs. resistance movement

  9. R F

  10. Function of Levers • Speed/ROM • Examples? • Common traits? • Rigid bar • Fixed point • Lever movement vs. resistance movement

  11. R F

  12. Components of a Lever System • Lever: Rigid bar • Fulcrum: Axis of rotation/fixed point • Force: • Applied force (F) • Resistance force (R) • Moment arm: d • Applied force • Resistance

  13. More Concepts • Mechanical advantage • Levers designed for force • Mechanical disadvantage • Levers designed for speed/ROM

  14. F R Mechanical advantage or disadvantage? How does mechanical advantage affect movement of the lever?

  15. Advantage: Small effort moves big resistance Disadvantage: Big movement required to move resistance a small distance

  16. Human Application? • Lever? Bones (Not always a bar) • Fulcrum? Joints • Applied force? Muscles • Resistance force? Weight of limb, external resistance

  17. Classification of Levers • Lever classification based on the relative location of: 1. Axis of rotation/fulcrum (A) 2. Resistance force (R) 3. Applied force (F) A R F

  18. First Class Lever • Center: (A) – Axis of rotation/fulcrum • Mechanical advantage • Mechanical disadvantage • Examples Crow bar Seesaw

  19. Advantage or disadvantage?

  20. Second Class Lever • Center: (R) – Resistance force • Mechanical advantage • Always • Mechanical disadvantage • Never • Examples Wheelbarrow Nutcracker

  21. Third Class Lever • Center: (F) – Applied force • Mechanical advantage • Never • Mechanical disadvantage • Always • Examples Rowing Shoveling Bat, tennis racket

  22. Baseball, tennis?

  23. Human Application • First class lever • Elbow extension against a resistance

  24. Mechanical advantage or disadvantage (R) – Resistance force (F) – Applied force (A) – Axis of rotation/fulcrum

  25. Human Application • Second class lever • Ankle plantar flexion

  26. Mechanical advantage or disadvantage? Not many in the body

  27. Human Application • Third class lever • Elbow flexion

  28. Mechanical advantage or disadvantage? Many of these in body

  29. In general, is the human body built for force application or speed/ROM?

More Related