1. Biomechanics
Animal Movement

2. Learning Objective
Explain the biomechanics of animal movement

3. Vocabulary Biomechanics Locomotion Kinesiology Anatomy Flexion
Extension
Adduction
Abduction
Myofibril
Myosin
Actin
Fascicle
Sarcomere
Synarthrosis
Amphiarthrosis

4. Biomechanics

5. Kinesiology Kinesiology is the study of human movement.
Biomechanics is one of the many academic sub disciplines of kinesiology.

6. What is Biomechanics?
Biomechanics - the study of the movement of living things using the science of mechanics
Biomechanics in kinesiology involves the precise description of human movement and the study of the causes of human movement.

7. Branches of Biomechanics
The major branches of mechanics used in most biomechanical studies.
Fluid mechanics - mechanics of fluids
Rigid body mechanics – solid bodies
Static – objects at rest
Dynamics – moving objects
Kinematics
Kinetics

8. Anatomy and Biomechanics
Anatomy - the study of the structure of the human body.
The study of biomechanics requires an understanding of the structure of musculoskeletal systems and their mechanical properties
Anatomy provides essential labels for musculoskeletal structures and joint motions relevant to human movement.

9. Muscles & Bone Movement

10. Ligaments
Attaches bone to bone

11. Tendons
Attach muscles to bones

12. Cartilage Cartilage Is a type of connective tissue that bends easily
Most of the skeleton of an embryo is cartilage
In adults, it only remains in the joints, the ears, the nose and at the end of the ribs
Cushions the joints

13. Bones

14. Bones Organs composed of moist, living tissues
Pink=fibrous connective, forms new bone after fractures
Blue=cartilage, forms cushion-like surface for joints
Inside are osteocytes that secrete bone matrix
Yellow bone marrow is stored fat from blood to bone
Red bone marrow produces RBC’s

15. The Appendicular Skeleton
Pectoral girdle:
Arm bones
Wrist and hand bones
Scapula (shoulder blades)
Clavicles (collar bones)
Pelvic girdle:
Pelvis
Leg bones
Ankle and foot bones

16. The Axial Skeleton Made up of Cranium (skull)
Vertebral column (backbone)
Sternum (breast bone)
Rib cage

17. Joints The place where bones meet is called a joint
Synarthrosis - immovable (i.e.. the skull)
Amphiarthrosis - moveable

18. Joints Moveable joints: Hinge = elbow and knee
Ball-and-Socket = shoulder and hip
Pivot = base of the skull
Gliding joint = wrists

19. Muscles

20. Muscle Structure Review

21. Dissecting Muscles
Muscles consist of bundles of muscle fibers (cells), oriented parallel to each other
Cells are bundles of myofibrils, which are composed of the contractile proteins actin (thin) and myosin (thick)
Proteins form a striped banding pattern that characterizes skeletal muscles
Contractile unit of skeletal muscle is the sarcomere

22. Contracting Filament Model
Sarcomere contracts when thin filaments slide over thick
Sarcomere shortens, but length of filaments don’t change
Heads of myosin (thick) filaments bind ATP so they can bind to actin (thin) filaments
Head produces power stroke which moves the actin toward the center of the sarcomere when ADP is released

23. Muscle Fiber Types
Slow fibers better designed for endurance Activities
Fast fiber - Weight lifting
Each muscle has a mix of the above types

24. Motion in Vertebrates
Motion and locomotion are produced by muscles pulling on bones.
Joints in the skeleton allow for parts of the body to flex and extend, allowing for motion. Ligaments attach bones to bones at the joints.
Muscles attach to bones by tendons. Origin is on a bone that remains stationary. Insertion is on a bone that moves.

25. Creating Movement Muscle action shortens or contracts muscles
The agonist moves the muscle while the antagonist reverses the movement
Antagonistic pairs of muscles are found in all animals

26. Joint Motions
Anatomy also has specific terminology de- scribing the major rotations of bones at joints. “Flexion” refers to a decrease in joint angle in the sagittal plane, while “extension” is motion increasing joint angle.
(a) Flexion and extension movements occur in a sagittal plane about a mediolateral axis
(b) adduction/abduction of the hip joint occurs in a frontal plane about an anteroposterior axis

27. Movement Flexion - decreases angle of a joint.
Extension - increases angle of a joint.
Abduction - movement away from midline.
Adduction - movement toward midline.
Rotation - turning around an axis.

28. Lever Systems
Muscles and bones work together around joints as systems of levers.
Lever systems of muscles and skeletons can be designed either for power or speed.
The ratio of load arm (resistance) to power arm (effort) determines the power.
A low load arm to power arm ratio provides high power but low speed
A high load arm to power arm ratio provides high speed but lower power.
Power L:P = 2
Speed L:P = 5

29. Bipedalism

30. Bipedalism
Upright walking in humans requires a fluid alternation between stance phase and swing phase activity for each leg.
Key features are the push-off, using the great toe at the beginning of the swing phase, and the heel-strike, at the beginning of the stance phase.

31. Arm swinging
Erect (bipedal)

32. resulted in a number of postcranial changes in the legs and feet . . .
Bipedal walking
resulted in a number of postcranial changes in the legs and feet . . .

33. Legs
Leg bones are much stouter in most primates and have more pronounced dorsal ridges

34. Comparison of muscles that act to extend the hip.
Understanding Physical Anthropology and Archaeology, 8th ed., p. 224

35. Hinge joint
A hinge joint allows flexing and extending along one plane.
Pairs of muscles work opposite one another to create motion.

36. Ball and socket joint
A ball and socket arrangement allows rotational movement.
Multiple pairs of muscles allow movement in a range of directions.

37. Advantages for Locomotion
It is easier to get food
It its easier to find shelter
An organism can move away from dangerous conditions or predators
It is easier to find mates and reproduce

38. Why Bipedalism?

39. Acheulian biface (“hand axe”)
Understanding Physical Anthropology and Archaeology, 9th ed., p. 239

42. Locomotion in Vertebrates

43. Types of Locomotion Swimming Locomotion on land
Gravity not a problem, but friction is
Water supports weight, but is dense and presents resistance
Legs as oars, jet-propelled, and undulating side to side or up and down
Streamlined body shapes aids increased speed
Locomotion on land
Need to be able to support self and overcome gravity
Air presents little resistance, but also little support
Energy expenditure to propel forward and keep from falling down
Muscles and skeleton more important that streamline shape

44. Types of Locomotion (cont.)
Hopping
Tendons in legs store energy when landing, like a spring for the next jump
Cost free energy boost
Rest with tail and hind feet on ground
Costs little energy to maintain
Walking and running
Overcome friction between foot and ground
Walking: 4 legged – 3 on ground all times; 2 legged – part of 1 at all times
Running: 4 legged – 2 -3 feet move at once if not all
Momentum stabilizes body position

45. Types of Locomotion (cont.)
Crawling
Friction adds considerable resistance because of increased contact
Undulate body side to side, inch forward, or peristalsis
Flying
Wings developed to completely overcome gravity
Shape must alter air current to create lift
Air pressure underneath is greater
All based on mircotubule or microfilament systems. Animals in motion
Leading edge thicker, lagging edge thinner; top convex, bottom concave or flat