1. KIN 275 Anatomy and Kinesiology Chad Dufrene

2. What is Kinesiology?

3. Kinesiology The study of human movement –A machine for the performance of work Areas of study: –Biomechanics –Musculoskeletal Anatomy –Neuromuscular Physiology

4. Reasons for Study Kinesiology is an area of study based in scientific principles, and utilized to improve human performance –Safety- avoidance of physical harm –Effectiveness- success or failure of meeting performance goals –Efficiency- achievement of motion with least amount of effort

5. Peformance Aspect Physical educators, coaches, and fitness professionals learn how to teach effective performance of basic and specialized skills –The purpose is successful participation and improvement of physical function –Examples include teaching proper form for an Olympic lift or the best method of shooting a basket

6. Medical Aspect Physical and Occupational therapists, and athletic trainers use principles of kinesiology in a more clinical and therapeutic way –Restoration of impaired function or compensation –Adequate performance of activities of daily living (ADLs) or rehabilitation from injury

7. Methods of Study There are primarily two methods to study kinesiology - Empirical laboratory analysis - Normal practice analysis

8. The Musculoskeletal System

9. The arrangement of bones, joints, and the muscles that provide locomotion This system, like similar ones in other areas of mechanics and physics, can be considered as an arrangement of levers –Bones are the levers that move in a circular fashion about a fulcrum (joint) when force from contracting muscles is applied

10. Bones There are 206 bones in the human skeleton, of which 177 are under voluntary control Two major divisions: –Axial- skull, spinal column, sternum and ribs –Appendicular- upper and lower extremities, including the scapula, clavicle, humerus, pelvis, femur, etc.

11. Axial vs. Appendicular

12. Bones Bone development is referred to as Osteogenesis –This term refers to both bone development throughout life and growth until puberty –Growth involves the epiphyses of bone calcifying from cartilage After puberty, this area fuses and no further long bone growth occurs

13. Types of Bones 1) Long- has a cylindrical shaft with broad and knobby ends –Examples: femur, tibia, clavicle 2) Short- small and chunky –Examples: carpals and tarsals (wrist and ankle) 3) Flat- platelike bones –Examples: sternum, scapulae, ribs 4) Irregular- no identifiable shape 5) Sesamoid- encased in soft tissue

14. Types of Bones

15. Joints Joints are primarily classified into two categories, based on the presence or absence of a cavity between bones containing synovial fluid –Diarthrosis- with cavity –Synarthrosis- without cavity –Further classification considers the shape or movement characteristics of the joint

16. Joints Diarthrodial joint types –Hinge- one plane of movement only (like a door) including the knee and elbow –Pivot- two long bones that can rotate around each other such as the radius and ulna –Ball-and-socket- spherical head of one bone fits into cup of another bone and allows all axes of movement; includes the shoulder and hip

17. Joints

18. Synoarthrodial joint types –Cartilaginous- joints united by cartilage such as the joints formed among all vertebrae –Fibrous- edges of bone are attached by fibrous tissue, but no movement occurs; the sutures of the skull are the primary examples –Ligamentous- two adjacent bones attached by ligament sheets or bands

19. Joints

20. Joint stability –The resistance to displacement when forces are applied Different joints have varying degrees of stability The elbow is considered a more stable joint than the knee due to the displacing or stabilizing effect of the agonist and antagonist muscles affecting them

21. Why is Joint Stability Important?

22. Joints Factors affecting joint stability –1) Shape of the bony structures- a deeper ball and socket arrangement (such as the hip) is more stable than a shallow one (such as the shoulder) –2) Ligamentous arrangements- joints are prevented from moving in restricted planes by these tough bands of tissue (but lose their effectiveness when overstretched)

23. Joints Factors affecting joint stability –3) Muscular arrangement- increased strength in certain muscles affects stability more than force generation –4) Fascia- fibrous connective tissue that form sheaths over and between muscles

24. Orientation of the Body

25. Terminology Proximal- closer to the trunk –Example: the shoulder is proximal to the elbow Distal- farther from the trunk –Example: the foot is distal to the knee

26. Terminology Superior- closer to the head (or above) –Example: the superior aspect of the clavicle is the top portion Inferior- farther from the head (or below) –Example: the inferior angle of the scapula is the bottom edge

27. Terminology Anterior- towards the front –Example: the anterior head of the deltoid faces forward Posterior- towards the back –Example: the posterior midline of the arm is an imaginary line that runs down the back of the arm

28. Terminology Medial- toward the midline of the body –Example: the Vastus Medialis is a muscle of the quadriceps on the inner thigh Lateral- toward the side of the body –Example: a lateral raise is a sideways motion of the hand or foot away from the body

29. Center of Gravity The point representing the exact weight center of an object –All segments of an object are perfectly balanced around the COG –In a sphere or cube, the COG is the geometric center; in a human it will differ based on body positioning –The center of gravity can be outside of the object, such as a boomerang

30. Center of Gravity Does your center of gravity change? Activity

31. Planes of the Body These are imaginary planes that represent the three dimensions of space Every movement of the human body can be categorized into a particular plane There is a perpendicular axis that corresponds to each plane –A good comparison might be a wheel as the plane and the axle as the axis

33. Planes of the Body Sagittal- the plane that divides the body into right and left halves –The bilateral axis passes through the body from right to left and vice/versa –Example movements on the sagittal plane include biceps curls, sit-ups, and front or back flips

34. Planes of the Body Frontal (coronal)- the plane that divides the body into front and back halves –The anteroposterior axis passes through the front and out the back of the body –Example movements on the frontal plane include side bends, jumping jacks, and dumbbell laterals

35. Planes of the Body Transverse- the plane that divides the body into top and bottom halves –The longitudinal (vertical) axis passes through the top of the head and out the bottom of the feet –Example movements on the longitudinal plane include twists and rotations

36. Plane Movements Sagittal plane –Flexion- decrease of joint angle around the bilateral axis Examples: curling the wrist upward, curling the heel backward, tipping the head forward –Extension- return from flexion, or increasing the joint angle around the bilateral axis Examples: extending the arm downward, straightening the knee, looking upwards

37. Plane Movements Frontal plane –Abduction- movement away from midline of the body around the anteroposterior axis Examples: lateral arm raise, lateral leg raise, or the first half of a jumping jack –Adduction- movement towards the midline of the body around the anteroposterior axis Examples: lateral arm and leg lowering, or the second half of a jumping jack

38. Plane Movements Transverse plane –Rotation of the head, neck, or pelvis Examples: turning head to the right or left, twisting body around –Pronation- twisting the forearm so that palm faces backward –Supination- twisting the forearm so that palm faces forward

39. Combination Plane Movement Circumduction- movement in a cone shape, around an axis of rotation across more than one plane –Example: circling the arm, leg, or trunk

40. Muscle Cells and Structure

41. Skeletal Muscle Structure Properties of muscular tissue –Contractility- the ability to generate tension while shortening to approximately half its resting length –Elasticity- the ability to be stretched beyond its resting length

42. Skeletal Muscle Structure Characteristics of a muscle cell –Long, thin strand –Multinucleated Contains several hundred nuclei per inch –Contraction Most of the cell interior is made up of the proteins Actin and Myosin (in bunches called myofibrils) which generate force

43. Skeletal Muscle Structure Characteristics of a Muscle Cell –Mitochondria The organelle within the cell where most energy production for muscle contraction occurs The majority of ATP is made here –Sarcoplasm The fluid inside the cell where many metabolic enzymes and all structures are found

45. Muscle Contraction Myofibrils are the long strands of contractile proteins arranged in parallel The Sarcomere is the smallest unit of contraction within the myofibril strand –A thick strand of Myosin is surrounded on both ends by thin strands of Actin –Myosin pulls both ends of Actin towards the center of the sarcomere to generate force

47. Fiber Type All skeletal muscles have similar quantities of at least 3 different fiber types: –Type I (Slow Twitch) –Type IIa (Intermediate Twitch) –Type IIb/x (Fast Twitch) The term “twitch” refers to the cell’s ability to shorten and generate tension

48. Fiber Type Type I (Slow Twitch) characteristics: –Very oxidative (uses O 2 to make lots of ATP) –Difficult to fatigue –Does not produce much lactic acid –Produces low tension and force –Has a greater capillary network (more blood supply) –Has a slow contractile speed

49. Fiber Type Type IIa (Intermediate Twitch): –Has properties of both slow and fast twitch –Produces more tension than type I –Fatigues more quickly than type I Studies have demonstrated that cardio exercise promotes a shift of many fast twitch fibers to type IIa

50. Fiber Type Type IIb or IIx (Fast Twitch): –Produces the most force –Recruited last and fatigues the quickest –Has very few mitochondria –Has many anaerobic enzymes –Produces much lactic acid

51. Fiber Arrangement All muscle cells are long and thin, but can be arranged in various ways to facilitate joint action Arrangement types: –Fusiform- tapered on both ends, and the individual cells run the entire length Example: Biceps Brachii –Pennate and Bipennate- shaped like a feather, the cells angle in toward a tendon Example: Gastrocnemius

52. Fiber Arrangement Arrangement types: –Fan shaped- flat muscle whose fibers taper from a wide end to a narrow end Example: Pectoralis Major –Quadrate- four sided flat muscle with parallel fibers Example: Rhomboids

53. Fiber Arrangement Angle of Pennation –This refers to the arrangement of fibers compared to the muscle’s line of action –Generally, the more parallel the arrangement to the line of action, the more velocity of shortening –The more angled the arrangement, the more force per unit can be generated

55. Muscle Function

56. Contraction Types It is important to note that a muscle contracts when it is generating force by shortening, staying the same length, or lengthening A common misconception is that a lengthening muscle is relaxing –A muscle only relaxes when it is still and not producing tension of any type

57. Contraction Types Concentric –The shortening portion of a dynamic (moving) contraction –The sarcomere gets shorter because heads on the myosin protein strand pull the actin strands toward the center –When many or all muscle cells act concentrically, the whole muscle shortens

58. Contraction Types Eccentric (negative) –The lengthening portion of the dynamic contraction –Force is still directed toward the center of the muscle, but the joint angle is allowed to increase –Myosin allows actin to move to the outside of the sarcomere much like lowering a rope with a weight attached

59. Contraction Types Isometric –Producing tension without any joint angle change –Pushing against a wall or pulling an immovable object are examples –Typically antagonistic muscles contract equally and the joint remains static

60. Muscle Roles Agonist (prime mover) –The muscle(s) most directly responsible for any given movement –Examples: the agonists of elbow flexion and knee extension are the biceps brachii and rectus femoris, respectively –There are assistant movers that can help as well in any given movement, such as the brachialis in elbow flexion

61. Muscle Roles Stabilizers –Muscles that contract statically or isometrically to support some part of the body during movement –Example: the teres major adducts the arm downward and the scapula outward and upward, but the scapula adductors stabilize it so only the arm moves downward

62. Muscle Roles Antagonists –The muscle that opposes the agonist in any given movement –In a dynamic contraction, the antagonist must relax throughout most of the movement –The antagonist can help as a stabilizer or brake at both ends of a dynamic contraction