Module 3- Biomechanics and Movement Principles

BIOMECHANICS:

The study of the mechanical laws governing movement of living organisms

KINESIOLOGY:

The study of the mechanics of human movement

ANATOMICAL POSITION:

The anatomically neutral body position facing forward with the arms at the sides of the body and palms and toes pointing straight ahead

Anterior or ventral

Front of the body or toward the front relative to another reference point

Posterior or dorsal

Back of the body or toward the back relative to another reference point

Superior

Above a reference point

Inferior

Below a reference point

Proximal

position closer to the center of the body relative to acreference point

Distal

Position farther from the reference point

Medial

Position relatively closer to the midline of the body

Lateral

Position relatively farther from the midline of the body

Prone

Lying facedown

Supine

Lying on one’s backside

Deep

Further beneath the surface relative to another reference point

Superficial

Closer to the surface relative to another reference point

Unilateral

Refers to only one side

Bilateral

Refers to both sides

Ipsilateral

On the same side

Contralateral

On the opposite side

Caudal

Toward the bottom

Cephalic

Toward the head

Volar

Relating to the palm of the hand or sole of the foot

Abduction

Movement away from the midline

Adduction

Movement toward the midline

Flexion

Movement decreasing the angle between two body parts

Extension

Movement increasing the angle between two body parts

Lateral flexion

Flexion in the frontal plane

Protraction

Abduction of the scapula

Retraction

Adduction of the scapula

Elevation

Movement in a superior direction

Depression

Movement in an inferior direction

Plantar flexion

Extension of the foot downward (inferiorly)

Dorsiflexion

Flexion of the foot upward (superiorly)

External rotation

Rotational movement away from the midline

Internal rotation

Rotational movement toward the midline

Circumduction

Circular movement of a limb extending from the joint where the movement is controlled

Inversion

Movement of the sole of the foot toward the median plane

Eversion

Movement of the sole of the foot away from the median plane

Pronation

Turning the palm or arch of the foot down

Supination

Turning the palm or arch of the foot up

Hyperextension

Position that extends beyond anatomical neutral

Ipsilateral

Same-side movement

Contralateral

Opposite-side movement

Lateral

Situated away from the midline

Medial

Situated toward or closer to the midlin

The anatomical planes of motion

used to describe the direction of movement.

The frontal plane

sometimes called the coronal plane, divides the body into anterior and posterior halves.

The sagittal plane

divides the body into left and right halves.

The transverse plane

divides the body into inferior and superior halves, and it runs perpendicular to the frontal and sagittal planes.

(ROM):

RANGE OF MOTION (ROM): The measurement of movement around a specific joint or body part

BALANCE:

An even distribution of weight enabling someone or something to maintain its center of gravity within a base of support

• CENTER OF GRAVITY:

• The hypothetical position in the body where the combined mass appears to be concentrated and the point around which gravity appears to act

  • The center of gravity is the point at which both body mass and weight are
    equally distributed

• MASS:

• The amount of matter in an object

• WEIGHT:

• The gravitational force of attraction on an object

• GRAVITY:

• The attraction between objects and the Earth

• BASE OF SUPPORT:

• The area beneath an object or person that includes every point of contact that the object or person makes with the supporting surface

• MUSCULAR FORCE:

• Involves the contraction of a muscle while exerting a force and performing work. It can be concentric, eccentric ,or isometric

• DYNAMIC BALANCE:

• The ability to remain upright and balanced when the body and/or arms and legs are in motion

• STATIC BALANCE:

• The ability to remain upright and balanced when the body is at rest

• Dynamic balance movement

• is where constant agonist-antagonist muscle contractions occur to maintain a certain position or posture.

• Ballistic movement

• is where inertial movement exists after an explosive
  or quick, maximum-force contraction; here is pre-tensing of the muscle in
  the eccentric contraction so the muscle can contract concentrically with
  maximum speed and quickness.

• Guided movement

• occurs when both the agonist and the antagonist contract to control the movement.

• line of gravity.

• When a line is drawn straight down from the center of gravity

  • To remain balanced, this line of gravity should fall within the base of support—the feet

• Muscular efficiency

• producing the right amount of force with the right muscles at the right time.

• Joint mobility

• is defined as the degree of movement around a joint before movement is restricted by surrounding tissues (tendons, ligaments, body fat, or muscles).

• joint stability

• the ability of the muscles around a joint to control movement or hold the joint in a fixed (stable) position

LAWS OF MOTION:

The laws of physics describing movement

NEWTON’S FIRST LAW: INERTIA

Newton’s first law states that a body in motion tends to stay in motion while a body at rest tends to stay at rest unless acted on by an outside force.

• FORCE:

• The interaction that creates work or physical change. Its components are magnitude, direction, point of application, and line of action

  • The interaction between two objects that results in a change to the motion of those objects is known as force.

3 types of force

• There are three types of force that can occur between two objects: compression, tensile, and shear.

• Compression force

• occurs when two surfaces press toward one another, causing them to be compacted.

  • An example of compression is the vertebrae of the spine

• Tensile force

• pulling two contact surfaces apart.

  • An example of tensile force could be hanging from a pull-up bar

• Shear force

• created when two surfaces move or glide across
  one another.

  • An example is a deadlift or the position of the hip in a hinge and resultant shear on the spine

• INERTIA:

• : The resistance to action or change and describes the acceleration and deceleration of the human body.

• ACCELERATION

• : The rate of change of velocity

• DECELERATION:

• A special type of acceleration where a person or object is slowing down

• NEWTON’S SECOND LAW: ACCELERATION

• -Newton’s second law of motion has two parts.

  • First, a change in acceleration of mass occurs in the same direction of the force causing it.

  • Second, the change of acceleration is directly proportional to the force causing it and inversely proportional to the mass of the body

• VELOCITY:

• The speed of an object and the direction it takes while moving

  • The velocity of an object refers to the direction and rate of
    its displacement

• FORCE-VELOCITY CURVE:

• A representation of the inverse relationship between force and velocity in muscle contraction

• MOMENTUM:

• The quantity of motion of a moving body, measured as a product of its mass and velocity

• EWTON’S THIRD LAW: ACTION AND REACTION-

• Newton’s third law states that for every action, there is an opposite and equal reaction

• SPEED:

• The ability to move the body in one direction as fast as possible

• (GRF):

• GROUND REACTION FORCE: The force the ground exerts on a body it is in contact with

FRICTION:

The resistance of relative motion that one surface or object encounters when moving over another

MUSCULAR CONTRACTION:

The shortening or resistance to lengthening of a muscle fiber

2 types of human joint motion:

• linear motion and angular motion.

• LINEAR MOTION:

• Movement along a line, straight or curved

• ANGULAR MOTION:

• Rotation around an axis

axis

Point of rotation around which a lever moves- also called a fulcrum

• Displacement

• Displacement describes the distance an object is moved from its starting point or location

• Angular displacement

• refers to the change in location, measured in degrees of rotation of an object that is rotating about an axis

• linear displacement

• is the distance an object moves in a straight line

• Distance

• refers to the total or sum of the length of travel.

• Friction

• a physical force affecting the body’s ability to create force, accelerate, and
  decelerate.

  • Friction is the force created by the resistance between two surfaces of two objects moving across one another

3 types of friction

• Friction can be
  • static,
  • sliding, or
  • rolling.

• Static friction

• is the friction of an object that does not move.

  • The forces against the object are equal to the forces being placed on it.

• Sliding friction

• is the friction between two surfaces where one or both are moving against one another.

  • it is sometimes referred to as kinetic friction.

• rolling friction

• is the force that resists a surface rolling across another such as a ball bearing or a wheel on a road surface

7 principles of biomechanics

force velocity relationship

production of maximum force

production of maximum velocity

stability

direction of movement

ground reaction forces (GRFs)

angular motion/ conservation of angular motion

• MECHANICAL ADVANTAGE:

• The ratio of force that creates meaningful movement compared to the force applied to generate the movement

  • it means the body is stronger at the established angle.