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1.1.c – Movement analysis

1.1.c – Movement analysis. Learning objectives. To understand the 3 different lever class systems To be able to describe the components of each lever system. To be able to explain the mechanical advantage of each of the lever and related movements .

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1.1.c – Movement analysis

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  1. 1.1.c – Movement analysis Learning objectives To understand the 3 different lever class systems To be able to describe the components of each lever system. To be able to explain the mechanical advantage of each of the lever and related movements. To understand the different planes of the body To understand the movement possible at each of the bodies planes and axes.

  2. Lever systems Watch me How does the body use levers to bring about movement?

  3. Levers The joints of our skeleton not only allow movement, they also act as LEVERS. The function of levers are to increase the speed at which a body can move.

  4. Levers The human body is a system of levers and pulleys which enables us to move. • The joint itself is the fulcrum (Pivot). • This fulcrum 'takes the strain' of pulling one near, or away from another bone.

  5. Levers The levers rotate around a series of joints. The force is provided by the muscles attached to the bone (think of the muscles acting as pulleys). The resistance comes from body weight and any implement used for sport (e.g. a bat or racquet).

  6. Levers Levers consist of three components: 1. Fulcrum (F) - the fixed point or pivot 2. Effort (E) – point where the force/effort is applied 3. Load (L) - point where the weight/resistance is coming from

  7. Class of lever • Levers can be classified as: • First class • Second class • Third class

  8. Class of lever – First Class This is a lever where the Fulcrum (pivot) occurs between the effort and load. Effort Load Lever Arm Fulcrum

  9. Class of lever – First Class The head is a good example of the action of a first-order lever in the body when the head and neck are being flexed and extended, as in nodding. Muscles in neck contracting Weight of head Neck joint First class levers can increase both effects of effort and the speed of a body.

  10. Class of lever – Second Class This lever occurs when the load is between the effort and the fulcrum. Load Lever Arm Effort Fulcrum

  11. Class of lever – Second Class When you raise up on to your toes you are using a second order lever. Weight of body and gravity Muscle working Ankle joint Second class levers tend to increase the effect of the effort force.

  12. Class of lever – Third Class This lever occurs when the effort lies between the fulcrum and load. This is very common in human movement Load Lever Arm Effort Fulcrum

  13. Class of lever – Third Class In terms of applying force this is a very inefficient lever, but it allows speed and range of movement. An example within the body is a bicep curl during flexion. The weight Arm Bicep muscle Elbow Third class levers can be used to increase the speed of a body.

  14. Mechanical Advantage The relative efficiency of each of the lever systems is called the ‘mechanical advantage’. Use the following equipment to explore how high you can propel the eraser. Effort Load Lever Arm Fulcrum How can the 1st class lever below be adjusted to increase or change how high the load can be propelled?

  15. Mechanical Advantage The body’s levers can be made even more effective by using rackets, oars, paddles, sticks and bats.

  16. Mechanical Advantage These pieces of equipment increase the length of the resistance arm of the lever. This in turn increases the speed at the end of the lever.

  17. Resistance Arm (RA) Effort Arm (EA) Effects of a lever on the human body The extent to which a lever can increase speed depends upon the relative lengths of the resistance arm (RA) and effort arm (EA). Effort Load Lever Arm EA - Part of the lever between the fulcrum & the effort RA - Part of the lever between the fulcrum & the load Fulcrum

  18. Resistance Arm (RA) Resistance arm The resistance arm (RA) is the part of the lever between the fulcrum and the resistance. The longer the resistance arm, the greater speed can be generated. Effort Load Lever Arm Fulcrum

  19. Effort Arm (EA) Effort arm The effort arm (EA) is the distance between the fulcrum and the effort; the longer the effort arm Effort Load Sporting implements are often used such as rackets or bats to increase the length of the effort arm which will increase the force that an object such as a ball is struck. Lever Arm Fulcrum

  20. Effort arm However the optimal length of an implement should be determined by the strength of the person handling. e.g. junior tennis rackets have been designed for this purpose.

  21. Mechanical Disadvantage Most levers in the body are third class levers where the resistance arm is always greater than the effort arm (mechanical disadvantage). The longer the resistance arm of the lever, the greater the speed at the end of it. So when bowling or passing a ball the performers arm should be fully extended to generate the most force and with the greatest speed.

  22. Planes and axes of movement Watch me Movement patterns and the bodies planes and axes

  23. Planes and axes of movement To help explain movement, the body can be viewed as having a series of imaginary slices/glass panes running through it. These are referred to as planes of movement

  24. Planes 1. The sagittal plane is a vertical plane that divides the body into rightand leftsides.

  25. Planes 2. The frontal plane is also a vertical plane but this divides the body into front and back.

  26. Planes 3. The transverse plane is a horizontal plane that divides the body into upper and lower halves.

  27. Axes of the body Axes are like invisible skewers running through the body. All movements rotate around one of the axes. • Longitudinal axis • Transverse axis • Frontal axis

  28. Axes of the body Longitudinal axis runs through the body vertically from the top to bottom.

  29. Axes of the body Transverse axis runs through the body horizontally from the left to right.

  30. Axes of the body Frontal axis runs through the body horizontally from the back to front.

  31. Planes & Axes of the body combined Movement in the sagittal plane about the transverse axis allows for front somersaults/forward roll. TRANSVERSE AXIS SAGITTAL PLANE

  32. Planes & Axes of the body combined Movement in the frontal plane about the frontal axis allows for cartwheels. FRONTAL AXIS FRONTAL PLANE

  33. Planes & Axes of the body combined Movement in the transverse plane about the longitudinal axis allows for a 360 degree twist. LONGITUDINAL AXIS TRANSVERSE PLANE

  34. Apply it! What has stuck with you?

  35. Apply it! What has stuck with you?

  36. Practice it! • Exam questions • Which one of the following describes a second class lever system? (1) • A The load is at the right-hand end of the lever • B The fulcrum is in the middle of the lever • C The load is in the middle of the lever • D The load and the fulcrum are at the same point on the lever • 2. Label the lever system below (4) • Lever class = _______________________ ___________ ___________ ___________

  37. Practice it! Exam questions 3. Which one of these shows how to calculate the mechanical advantage of a lever? (1) A Effort arm x weight (resistance) arm B Effort arm ÷ weight (resistance) arm C Effort arm + weight (resistance) arm D Effort arm - weight (resistance) arm

  38. Practice it! Exam questions 4. Analyse how the following parts of the lever system allow the weight trainer in Figure 5 to lift the weight. • Fulcrum (2) • (ii) Effort (2)

  39. Practice it! Exam questions 5. Figure 4 shows a basketball player jumping to execute a shot. Draw the lever system which operates at the ankle joint in the space below. Label the fulcrum, effort and load. (1)

  40. Practice it! Load • Marks Scheme: • C • i) Third class lever • B • One mark for linking bone or muscle to component of lever system and one mark for linking this to its use in the biceps curl to lift the weight. For example: Fulcrum – elbow is the fulcrum (1) which allows the arm to bend/flex (1) Effort – biceps muscle provide the effort (1) which allows the weight lifter to lift the weight (1) Effort Fulcrum

  41. Practice it! Marks Scheme: 5. Award one mark for labelling the effort, load / resistance and fulcrum in the correct order.

  42. Practice it! Exam questions 1. Figure 1 shows one plane and one axis of the human body. The plane is represented by the square. The axis is represented by the dotted line. (1) Identify the plane and axis shown in Figure 1. A Sagittal plane and transverse axis B Frontal plane and longitudinal axis C Transverse plane and transverse axis D Transverse plane and longitudinal axis

  43. Practice it! • Exam questions • 2. Which one of the following statements is false? (1) • The movement at the elbow joint during a biceps curl is an • example of flexion and extension. • (B) The deltoid at the shoulder joint during a biceps curl is an • example of a fixator. • (C) Most of the lever systems that provide movement in sport are examples of third class levers. • (D) An example of a second class lever is a tennis player using their elbow joint during a forehand shot.

  44. Practice it! Exam questions 3. The dancer in the picture below has performed a movement that has passed through the frontal plane. (1) Is this statement true or false?

  45. Practice it! • Marks Scheme: • D • (D) – An example of a second class lever is a tennis player using their elbow joint during a forehand shot • False

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