Kinesiology

1. Kinesiology

2. Chapter Outline The musculoskeletal system Human strength and power Sources of resistance to muscle contraction Joint biomechanics: concerns in lifting Movement analysis and exercise prescription

3. Muscle Pulling Force Manifested As a Pushing Force

4. Muscle Pulling Force Manifested As a Pulling Force

5. Front View of Adult Male Human Skeleton

6. Rear View of Adult Male Human Skeleton

7. The Vertebral Column

8. Front View of Adult Male Human Skeletal Musculature

9. Rear View of Adult Male Human Skeletal Musculature

10. A Lever

11. A First-Class Lever (The Forearm)

12. A Second-Class Lever (The Foot)

13. A Third-Class Lever (The Forearm)

14. Lever Systems Classified systems of torque Relative positions of force, resistance, and axis of rotation vary in the different types or classes of levers

15. Classes of Levers • First Class – The applied force and the resistance are on opposite sides of the fulcrum. • Second Class – The resistance is between the applied force and the fulcrum. • Third Class – The applied force is between the resistance and the fulcrum.

16. applied force resistance force arm resistance arm fulcrum First Class Lever

17. force arm resistance arm resistance applied force fulcrum Second Class Lever

18. resistance arm force arm resistance applied force fulcrum Third Class Lever

19. Levers In The Musculo-Skeletal System • Most are third class levers • This system produces a disadvantage for force but an advantage for speed of movement

20. FM FRO DFA R DRA Levers In The Musculo-Skeletal System Most of the musculo-skeletal system consists of third class levers. The resistance arm is longer than the force arm.

21. B A Levers In The Musculo-Skeletal System The musculo-skeletal lever systems generally favor speed over strength. In the time that the muscle insertion moves a given distance (red arrow), the resistance moves a much greater distance (blue arrow).

22. B A Levers In The Musculo-Skeletal System In other words, the end of a limb is moving at a greater velocity than the attachments of the muscles that produce that movement.

23. q Strength vs. Speed in Skeletal Muscle • In a muscle contraction acting on a limb the resistance moves through the same angular displacement as the muscle insertion. • The angular velocity of the muscle insertion (A) is equal to the angular velocity of the load (B) B A

24. FM FRO DFA R DRA Strength vs. Speed in Skeletal Muscle If DFA = 3 cm and DRA = 30 cm • The relative speed of the resistance to the muscle insertion = DRA/DFA = (30 cm)/(3 cm) = 10 • This means that the resistance is moving at 10 times the velocity of the muscle insertion

25. Levers in the Musculo-Skeletal System • Not all levers in the musculo-skeletal system are third class. • When performing toe rises the ankle becomes a second class lever system. R FM DRA DFA fulcrum

26.  Most of the skeletal muscles operate at a considerable mechanical disadvantage. Thus, during sports and other physical activities, forces in the muscles and tendons are much higher than those exerted by the hands or feet on external objects or the ground.

27. Types of Muscle Contractions • Isometric • Tension is developed • No movement of the joint • Isotonic • Constant resistance • Variable speed • Isokinetic • Constant speed of contraction • Variable resistance

28. Speed vs. Force Movements • Speed movements • Joints move in sequence • Walking, running • Force movements • Joints move simultaneously • Squat, bench press

29. q r Linear vs. Angular Velocity B A A B

31. If you think you're No. 1, you're never going to reach potential. So each day, we battle. And each day, it changes. Lelan Rogers – Syracuse University Lacrosse Assistant Coach

32. Mechanical Principles • Mass • Weight • Inertia • Speed • Velocity • Acceleration

34. Linear Acceleration (in velocity direction) • This is the familiar stoplight acceleration along a straight line • Zero to Sixty-Seven (30 m/s) in 5 seconds: • 30 m/s in 5 seconds means 6 m/s2 (~0.6g) • Typical car acceleration, normal driving ~0.2g

35. Curves & Centripetal Forces • Going around a curve smushes you against window • Understand this as inertia: you want to go straight your body wants to keep going straight but the car is accelerating towards the center of the curve

36. Centripetal Forces • The car is accelerated toward the center of the curve by a centripetal (center seeking) force Centripetal Force on car velocity of car (and the way you’d rather go)

37. Introduction • Projectile Motion: Motion through the air without a propulsion

39. Part 1.Motion of Objects Projected Horizontally

40. y v0 x

41. y x

42. y x

43. y x

44. y x

45. y • Motion is accelerated • Acceleration is constant, and downward • a = g = -10 m/s2 • The horizontal (x) component of velocity is constant • The horizontal and vertical motions are independent of each other, but they have a common time g = -10 m/s2 x

46. y h v02 > v01 v01 x Trajectory x = v0 t y = h + ½ g t2 Parabola, open down Eliminate time, t t = x/v0 y = h + ½ g (x/v0)2 y = h + ½ (g/v02) x2 y = ½ (g/v02) x2 + h

47. y h x Changes in Vx

48. Part 2.Motion of objects projected at an angle

49. y a = g = - 9.81m/s2 • Motion is accelerated • Acceleration is constant, and downward • a = g = -9.81m/s2 • The horizontal (x) component of velocity is constant • The horizontal and vertical motions are independent of each other, but they have a common time x

50. Trajectory and Horizontal Range vi = 25 m/s