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

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

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

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

21. 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). A B

22. Levers In The Musculo-Skeletal SystemB
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. Strength vs. Speed in Skeletal Muscleq
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. Strength vs. Speed in Skeletal Muscle
DFA
DRA FM R
FRO
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. Linear vs. Angular Velocityq B A A B

31. If you think you're No. 1, you're never going to reach potential
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)
Motion in our Daily Lives
04/28/2008
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
Lecture 10

35. Curves & Centripetal Forces
Motion in our Daily Lives
04/28/2008
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
Lecture 10

36. Motion in our Daily Lives
04/28/2008
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)
Lecture 10

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. g = -10 m/s2 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. Trajectory y = h + ½ (g/v02) x2 y = ½ (g/v02) x2 + h x = v0 t
y = h + ½ g t2
Parabola, open down
Eliminate time, t
v02 > v01
v01
t = x/v0
y = h + ½ g (x/v0)2
y = h + ½ (g/v02) x2
y = ½ (g/v02) x2 + h

47. Changes in Vx y x h

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

49. Acceleration is constant, and downward a = g = -9.81m/s2 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

51. Velocity Final speed = initial speed (conservation of energy)
Impact angle = - launch angle (symmetry of parabola)

52. PROJECTILE MOTION - SUMMARY
Projectile motion is motion with a constant horizontal velocity combined with a constant vertical acceleration
The projectile moves along a parabola

53. When a weight is held in a static position or when it is moved at a constant velocity, it exerts constant resistance, only in the downward direction.
Equilibrium
However, upward or lateral acceleration of the weight requires additional force.
Overcoming the effect of gravity

54. Stability
Center of gravity
Line of gravity
Base of support

55. Center of Gravity

61. Anatomical Planes of the Human Body

62. Muscle Fiber Arrangements

63. 
Resistance training is quite safe compared with other sports and fitness activities. Prudence can keep injuries to a minimum. Basic safety principles include good lifting form, appropriate resistance, accommodation to injuries, balance, and variety.

64. 
Specificity is a major consideration when designing an exercise program to improve performance in a particular sport activity. The sport movement must be analyzed qualitatively or quantitatively to determine the specific joint movements that contribute to the whole-body movement. Exercises that use similar joint movements are then emphasized in the resistance training program.

66. Stability Base of support (bos) Center of gravity (cog)/center of mass
Line of gravity (log)

67. Equilibrium and Movement
Body segments moved independently
Mass is redistributed
Changes body’s cog
As long as the cog is located over the bos the body will remain in equilibrium

68. Stability Resistance to movement mass  log  bos
Move weight in the direction of the oncoming force

69. Dynamic Balance Constant interaction of forces
Move body in a given direction at a given speed
Smooth transition of cog from one bos to the next

70. Dynamic Balance

71. Force
F = m(a)
Any influence that can change the state of motion of an object
The objective of movement must be considered

72. Magnitude of Force
Inertia of object and other resisting forces must be overcome by enough force for movement to occur
Force must have adequate magnitude to overcome inertia
Liner movement  the closer the force is applied to the cog the less force needed
Rotational movement  the farther the force is applied to the cog the less force is needed
Objects with a fixed point  unless the force is applied through the point of fixation, the object will rotate

73. MOM and DAD
MOM
Maximize
Optimize
Minimize

74. Muscle Pulling Force Manifested As a Pushing Force

75. Muscle Pulling Force Manifested As a Pulling Force

76. Angular motion
Object rotates around an axis
Types
Turn
Spin
Swing

77. Athlete’s body Predominantly rotational Muscles pull on bones
Bones rotate at joints

78. Levers Simple machines that transmit mechanical energy
Components of a lever
Rigid object that rotates around an axis
Applied force
Resistance (opposes force)
Produce torque
Turning effect
Increased by magnifying force and/or distance from axis of rotation

79. 2 functions of a lever system
Magnify speed and distance
Magnify force
Can not occur at the same time

80. Short Lever Arm

81. Long Lever Arm

82. Optimize

83. First Class. In a first class lever, the weight to be moved is at one end of the lever, the applied force is at the other end, and the fulcrum (the pivot or turning point) is between the two.
b. Second Class. In a second class lever, the weight to be moved is between the applied force and the fulcrum. This type of lever enables a weight to be moved with less force than would be required without a lever. (Many feel that there are no second class levers in the human body.)
c. Third Class. In a third class lever, the weight to be moved is at one end of the lever, the fulcrum is at the other end, and the applied force is between the weight and the fulcrum. This type of lever provides speed, but a greater amount of force is required for a given weight. This is the most common type of lever in the human body.

84. First Class Lever The Forearm
Magnify either force or speed and distance

85. Second Class Lever The Foot
Magnify force at the expense of speed and distance

86. Third Class Lever The Forearm
Magnify speed and distance at the expense of force.
Predominate the body – most muscles apply great force in order to move light resistances over large distances at great speed.

87. Human Body Levers Most are long Distal ends capable of moving rapidly
Body movements
Swift, wide movements
Low force
Tasks involving rapid movement with light objects are easily performed
Very forceful movements may require an anchoring to secure a mechanical advantage

88. Bats, sticks, clubs and racquets
Increase lever arm length
May increase force applied
Demands more force generated by muscles

89. Movement of the Body
Outcome of a system of levers that operate together
Speed
levers function is sequence
Swinging a bat
Great force
levers function simultaneously
Squat or bench press

90. Speed

91. Force

92. Inertia
A body in motion will stay in motion a body at rest will stay at rest unless acted on by an outside force
Outside forces include
Gravity
Air resistance
Tuff guys

93. Acceleration Movement response Depends on External force applied
Resistance to movement (inertia)

94. Formulas
Abbreviations
Distance (d)
Velocity (V)
Force (F)
Mass (m)
Acceleration (a)
Time (t)
Distance (d)
D=Vt
Force (F)
F=ma
Work (W)
W=Fd or W=mad
Power (P)
P=W/t or P=mad/t or P=FV

95. Linear Acceleration Change in velocity As V and t, a
Only experienced when force is applied
When force stops, a new speed is achieved
The direction of acceleration is in the same direction as the force applied
Acceleration is proportional to force applied

96. Angular Acceleration Rate of change of angular speed or direction
Large change in angular velocity + small amount of time = large angular acceleration
A lever arm only experiences angular acceleration when an external torque is applied
Torque stops  angular acceleration stops
Angular acceleration is in the direction of the torque and is proportional to the amount of torque

97. Constant Velocity
Zero acceleration
Equal and opposing forces are encountered
Forces cancel out  no acceleration or deceleration
Acceleration Caused by Gravity
9.8m/s2
A falling object accelerates at the rate of 9.8m/s each second it falls

98. Acceleration Due to Gravity

99. Radial Acceleration Direction change caused by centripetal force
Mass of object + curve radius + speed + centripetal force
Aimed along the circular path at any instant
The force responsible for change of direction
mass,  centripetal force needed
Instantaneous direction change  as turn radius 

100. Hammer Throw

101. Every action has an equal and opposite reaction
Action/Reaction
Every action has an equal and opposite reaction

102. mass, resistance to change
Linear Motion
mass, resistance to change

103. Movement of the Human Body
Caused by a body segment exerting force when in contact with a surface
The reaction of the surface moves the body
sand vs. concrete
Runner – propelled forward with an equal and opposite force pushed backward against the ground
Surface has sufficient friction (resistance to slipping)

105. Torque and Action/Reaction
Every torque exerted had an equal an opposite torque
Change in angular momentum must be caused by a force that is equal and opposite

106. When Action/Reaction is not desired Controlled
Undesired action must be absorbed
Energy can not be created or destroyed
Purpose of pads

107. Performing Actions in a Standing Position
Counter pressure of the ground
 accuracy of movement
Base of support