Exam 1 - Dance Science

Frontal/Vertical/Coronal Plane

• Up and Down

• Anterior to Posterior

• Abduction and Adduction

Sagittal Plane

• Divides body into right and left

• Medial to lateral

• Flexion and Extension

Transverse/Horizontal Plane

• Divides body into upper and lower

• Superior to inferior (longitudinal)

• Rotation

Gravity

Pulls mass towards the earth, creating a vertical line

Center of Gravity

Point of equilibrium where the 3 body planes intersect, also called the “Cardinal Point”

Base of Support

The area of contact between the body and supporting surface which inclkudes the point of contact and the area in between

Line of Gravity

The intersection of the frontal and sagittal planes

Stable Balance

Line of gravity centered over base of support

Off Set Balance

Line of gravity toward the edge of base of support

Dynamic Balance

Line of gravity outside base of support

Anti-Gravity Muscles

Muscles that are constantly needed in a standing position to prevent falling down

Axial Skeleton

• Skull

• Mandible

• Hyoid Bone

• Vertebral Column

• Rib Cage

• Sacrum

• Coccyx

Appendicular Skeleton

• Shoulder Girdle

• Upper Limbs

• Innominate Bones

• Lower Limbs

Major Types of Forces

• Tensile - forces that pull structures apart

• Compression - pushes together

• Torsion/Shear - causes displacement of structure

Bone Structure

• Compact Bone - denser outer covering

• Spongy Bone - inner honeycomb-like structure

Calcification

• Chondrocytes in the center of the shaft hypertrophy (harden)

• Minerals are deposited within the matrix

• The passage of nutrients is cut off, and chondrocytes die

• Ossification occurs within plate, no more bone growth

Wolff’s Law

• Bone tissue responds to stress, and builds up in areas that need it

• Bone remodeling calls for the bone to get weaker before it gets stronger

Bone Remodeling

• Osteoclasts are responsible for weakening the bone by crating cavities (PACMAN)

• Osteoblasts lay down new areas of denser bone

Fibrous Joints

• Sutures of the skull

• Interosseous membrane

Cartilaginous Joints

• Pubic symphysis

• Ribs to sternum

• Between vertebrae

Synovial Joints

• Joint capsule

• Synovial membrane

• Hyaline cartilage

Non-axial Joints

Does not move around a specific axis, meaning they permit only flat slipping or gliding movements rather than angular or rotational motion

• Carpal Joints

Pivot/Uni-axial Joints

A type of body joint where one bone spins or rotates inside a ring made of another bone and a ligament

• Elbows

• Knees

Ellipsoidal/Bi-axial Joints

Allow movement in two different directions or planes, but they do not let the bone twist or rotate in a full circle

• Fingers

Ball and Socket/Tri-axial Joints

Freely moveable joints that allow movement in three different directions or planes

• Shoulder

• Thigh

Osteoarthritis

Wear and tear arthritis, causes bone to rest on bone

Rheumatoid Arthritis

A virus which causes the synovial joints to swell

Ligaments

Connect bone to bone

• Made of collagen and elastin

Tendons

Connect Muscle to bone

Causes of restriction to movement at a joint

• The bone structure itself

• The ligamentous structure supporting the joint

• Muscular restrictions

Proprioceptors

• Muscle spindles

• Golgi tendon organs

• Semicircular canals in inner ear

3 Types of Muscles

• Smooth

• Cardiac

• Skeletal

Structure of Skeletal Muscle

• Myofibrils

• Sarcolemma: plasma membrane that contains myofibrils

• Fibers: made of myofibrils

• Sarcomeres: longitudinal segments of myofibril

• Sarcoplasm: fluid in sarcomere that contains Actin and Myosin

Roles of Muscles

• Produce force in only one direction

• Only pull, telescoping action when they contract

• Any energy in the muscle produces contraction

Agonist

Muscle which contracts to produce a given action

Antagonist

Muscle which contracts to produce the opposite action

Prime Mover

The muscle group that is most effective in the production of a given action

Assistors

Muscles that help the prime mover produce a certain action when the prime mover is not sufficient

Synergists

2 or more muscle groups perform the identical action at the joint

Performers

Muscles the produce the actual action

Stabilizers

Muscles that provide the stabilization so that movement is possible

All or None Law

The principle that an individual nerve or muscle cell will either respond completely to a stimulus or not at all, with the strength of the response staying the same no matter how strong the stimulus is

Recruitment

More motor units are called upon to make muscle contractions stronger

Summation

Calls for impulses to be sent faster

Graded Contraction

A muscle contraction that changes its strength and force depending on what the body needs

• It lets you use a small amount of force to pick up a light object, like a pen.

• It lets you use a large amount of force to lift a heavy object, like a heavy box.

Aerobic

With oxygen

• Activity of longer duration

Anaerobic

Without oxygen

• ATP forms lactic acid

Muscle Spindle (Proprioceptor)

Responds to stretch of the belly of the muscle

Stretch Reflex

Reflexive contraction that results in the slight discomfort and resistance when stretching

Blocking the Stretch Reflex

• Long sustained muscle stretches for 20-30 seconds

• Reciprocal Inhibition: A max contraction of a given muscle will temporarily block the stretch reflex of the opposite muscle

Golgi Tendon (Proprioceptor)

• Located at the tendon level

• Responds to stretch and protects

Significant Contributions of Early Kinesiologists

• Hippocrates: first medic to clinically look at the body and analyze movement

• Aristotle: found consistencies in the design and patterns of different muscles

• Galen: discovered agonists and antagonists

• Da Vinci: Drew the Vitruvian man

Galvani

Discovered electrical potential of muscles whid led to development of Electromyography

Basmajian

Discovered how mich electrical activity is in muscle contraction and the basic analysis of weight shift

Adduction

Movement toward the midline of the body

• Lowering your arms from a raised "T" shape back down to your sides, or pulling your arms down during a pull-up

Abduction

Movement away from the midline of the body

• Raising your arms up to the sides to form a "T" shape.

Rotation

Movement around the central axis of a lever

• Keeping your leg straight and pointing your toes inward toward each other.

Extension

Increasing the angle between 2 levers

Hyperextension

Increasing the angle between 2 levers beyond 180 degrees

Circumduction

Movement with one joint as the fixed point and the distal end describing a cone

• Rotating ankle

Dorsiflexion

Flexing the foot

Plantarflexion

Pointing the foot

Supination

Palms up

1

• Knee Joint

• Medio to lateral

• Sagittal Plane

• Flexion and extension

2

• Thigh joint

• Longitudinal

• Transverse Plane

• Internal Rotation

3

• Shoulder Joint

• Longitudinal

• Transverse Plane

• Internal Rotation

4

• Intervertebral joints

• Medio to lateral

• Sagittal Plane

• Spinal flexion and spinal extension

5

• Elbow joint

• Longitudinal

• Transverse Plane

• Supination and pronation

6

• Thigh Joint

• Anterior to posterior

• Frontal Plane

• Abduction and adduction

7

• Shoulder joint

• Medio to lateral

• Sagittal plane

• Flexion and extension

8

• Ankle joint

• Medio to lateral

• Sagittal plane

• Dorsiflexion and plantarflexion

9

• Thigh joint

• Longitudinal

• Transverse plane

• External rotation

10

• Shoulder joint

• Longitudinal

• Transverse plane

• External rotation

11

• Elbow joint

• Anterior to posterior

• Frontal plane

• Flexion and extension

12

• Thigh joint

• Medio to lateral

• Sagittal plane

• Flexion and extension