1. Chapter 13 Biomechanical Analysis to Improve Technique

2. Forms of Motion n General motion n Linear (translation) motion –Rectilinear motion - motion along a straight line. –Curvilinear motion - motion along a curved line. n Angular motion (fixed point)

3. Keys Areas of Study n Kinematics – study of the time and space aspects of movement n Kinetics – study of the force and energy aspects of a performance.

4. Kinetics n Kinetics - the study of forces. n Basic concepts related to kinetics: –Mass - the quantity of matter a body possesses. –Inertia - resistance to a change in state of motion. Directly proportional to mass.

5. Qualitative Analysis of Human Movement n Requires knowledge of the specific biomechanical purpose of the movement and the ability to detect the causes of errors. n Visual observation.

6. Analyzing Skills Qualitatively n Analyze technique and outcome. n If technique (process) is correct, outcome (product) will be too.

7. Analyzing Skills Qualitatively n Too frequently we coach or teach to the outcome rather than the technique or process that produces the outcome.

8. Role of Movement Analyst Bob Norman (1976) & Shirl Hoffman (1977) n Recognize symptoms of malperformance –Is performance acceptable? Is the goal attained? »Process vs Product n Trouble-shoot the cause of the malperformance »Critical ability lacking »Skill performance deficiency »Psychosocial problem n Prescribe cues to correct malperformance –Make the appropriate intervention

9. Analyzing Skills Qualitatively n Hoffmann flow chart

10. Was goal attained? Define and clarify new goal Critical ability lacking? Skill performance deficiency? Psycho-social problems? Redefine goal Remedy deficit Technique error? Perceptual error? Decision error? Cause of error known? Modify technique Refocus attention on relevant stimuli Emphasize temporal factors Performance management techniques Yes No Yes No Y Yes Ample observations? Adequate info base? No

11. Critical ability lacking If there is a mismatch between the individual and the environment - modify the environment

12. Mismatched Environment Adapt the environment to the individual to enhance chances of success.

13. Photo by Erica Trout in Parade Magazine, 9/19/04

14. Was goal attained? Define and clarify new goal Critical ability lacking? Skill performance deficiency? Psycho-social problems? Redefine goal Remedy deficit Technique error? Perceptual error? Decision error? Cause of error known? Modify technique Refocus attention on relevant stimuli Emphasize temporal factors Performance management techniques Yes No Yes No Y Yes Ample observations? Adequate info base? No

15. Skill Performance Deficiency n We will come back to this shortly

16. Was goal attained? Define and clarify new goal Critical ability lacking? Skill performance deficiency? Psycho-social problems? Redefine goal Remedy deficit Technique error? Perceptual error? Decision error? Cause of error known? Modify technique Refocus attention on relevant stimuli Emphasize temporal factors Performance management techniques Yes No Yes No Y Yes Ample observations? Adequate info base? No

17. Psychosocial problems.

18. I joined a health club last year, spent about $400 and haven’t lost a pound. Apparently, you have to show up.

19. Psychosocial problems.

20. Bob Norman n “One of the most difficult problems which confronts coaches and teachers when they are teaching fundamental skills is that of detecting errors accurately and specifically.”

21. Bob Norman n “If the error detection is inaccurate or non- specific, the quality of instruction and the consequent learning on the part of the athletes will be poor.”

22. Bob Norman Causes, symptoms and idiosyncrasies n Cause – the actual mechanical reason for a movement. Forces, acceleration, etc n Symptom – a side-effect of a movement. Follow through. n Idiosyncrasy – something that occurs during movement that has nothing mechanically to do with the movement. Tongue sticking out

23. Bob Norman n In teaching and coaching, we too often focus on the symptoms and idiosyncrasies of a performance rather than the actual mechanics that determine what happens.

24. Skill Performance Deficiency n Mechanical objective of a skill »momentum in particular direction(s)

25. Bob Norman (1976) n Mechanical objective of a skill n Idiosyncrasy –individual nuance of performance that has no direct influence on mechanics of performance »Michael Jordan’s tongue »Various batting stances

26. How Often Have You Heard This? n You need to stand ____ with the bat ______ to hit the ball.

27. Unwarranted focus on static position of batting stance

30. Some People Just Don’t Get It? “Physics is not the only science important in the game of baseball; it’s also a game of psychology, of pitchers trying to stare down batters, and batters trying to intimidate pitchers. And no matter what you tell me, I don’t believe that some guy standing in the batter’s box with his bat dangling loosely from his hands has nearly as much power as a guy snarling and gripping the bat hard, waving it menacingly over his head. It may not be good science, but I’ll bet the second guy gets more hits.” Suzanne Sparacino, Commack NY Letter to the editor, Discover magazine.

31. Bob Norman (1976) n Mechanical objective of a skill n Idiosyncracy n Symptom of an error –what we see go wrong (kinematics) »not high enough »not fast enough »wrong direction »body positions

32. How Often Have You Heard This? n Swing level

34. Paul Popovich March 29, 1993. Swing Level?

35. Say what you mean!

36. Another Example n The Follow Through n Basketball shooting - “Goose neck”

37. Follow through? n “As the knees straighten, release the ball and follow through with a flick of the wrist” n “Follow through by snapping your wrist down, like you are reaching into the cookie jar.” n “As you release the ball, snap your wrist downward, as if you are waving "good-bye" (called a "follow through"). When done correctly, the wrist snap will give the ball the correct amount of spin it needs.”

38. Follow through Game-winning shot vs Utah Jazz 19**??? Symptom or Cause?

40. Another Example n Pitchers are told to “lead with the elbow”

41. Lead with the elbow

42. Shoulder External Rotation: Symptom? or Cause? of Great Performance?

43. Bob Norman (1976) n Mechanical objective of a skill n Idiosyncracy n Symptom of an error n Cause of an error –the underlying reason for the poor performance »mechanically: error in impulse application

44. Mechanical Phases of skill performance n Ritual Phase –Full of idiosyncrasies, useful for mental focus n Preparation –Wind up »Storage of elastic energy, increase ROM (Benefits?) n Execution –Acceleration »Apply impulse to the body in the desired direction n Follow through –Bring moving parts to rest »Safety, symptom of good performance

45. Typical Coaching Advice

49. More Glaring Examples of Bad Coaching

50. Volleyball Underhand Serve Peer Rating Evaluation Sheet from a middle school session at IAHPERD conference 1.Is the arm which is holding the ball across the front of the body? 2.Is the ball held at or below the waist? 3.Is the body bent at the waist before the person hits the ball? 4.Is the striking arm brought back with a straight elbow? 5.Is the ball hit from a short toss or out of the hand? 6.Does the hitting arm swing from the shoulder? 7.Does the hitting arm swing straight, not across the body? 8.Is the person stepping or standing with opposition? 9.Is there a weight shift from the rear foot to the front foot when the ball is hit? 10.Does the striking hand follow through at least as high as the head after the ball is hit?

51. Possible reasons why the elderly walk slower n Not willing to walk faster –Wise enough to know that walking faster changes nothing –Careful stepping due to slowing of reflexes –Cautious –Afraid of road hazards –Afraid of falls due to OP, other catastrophes n Not able to walk faster –Reduced ability to maintain dynamic balance –Reduced ROMs –Reduced contents of fast-twitch muscle fiber –Joint or muscle pathologies –Reduce CV fitness

52. Help! I’ve Fallen and I Can’t Get Up n Phenomenon –Individual cannot rise from the ground »After a fall »Gardening »Housecare –Why not? List possible reasons, according to the Hoffman Checklist n Importance: Develop an intervention for prevention »Strength training? »Flexibility training? »Technique Training What technique? Old vs Young? Healthy vs Infirm?What technique? Old vs Young? Healthy vs Infirm?

53. Analyzing Skills Qualitatively n Understand the specific purpose of the skill from a biomechanical perspective. n Identify the cause of technique error. n Familiarity with the skill aids in analysis.

54. Planning a Qualitative Analysis n Identify the major questions of interest (What is the problem?). n Determine the optimal perspective from which to view the movement. n Select the optimal viewing distance.

55. Planning a Qualitative Analysis n Determine the optimal number of trials necessary to perform the analysis. n Determine the effect of environmental factors on performance. n Will a video recording help in analysis?

56. Conducting a Qualitative Analysis n Every performance of a motor skill is affected by the physical characteristics of the performer.

57. Conducting a Qualitative Analysis n These include the performer's critical abilities: –age, –gender, –anthropometrics, –the developmental and skill levels at which the performer is operating, –and any special physical or personality traits that may impact performance.

58. Conducting a Qualitative Analysis n Providing a novice, preschool-aged performer with cues for a skilled, mature performance may be counterproductive, since children are not simply scaled-down adults.

59. Conducting a Qualitative Analysis n The analyst should not overlook the potential value of non-visual forms of information (sound). n Another potential source of information is feedback from the performer.

60. Conducting a Qualitative Analysis n Adding more than one analyst may enhance the thoroughness of the analysis.

61. Quantifying Kinetics n Tools for measuring kinetic quantities: –EMG –Dynamography –Force platforms

62. Conducting a Qualitative Analysis Tools for measuring kinematic quantities: Cinematography and videography. Optoelectric movement monitoring systems (LEDs)

63. Conducting a Qualitative Analysis Electrogoniometers. Timing devices. Accelerometers.