Intro to Kinesiology & Biomechanics

PPT 1

Kinesiology

study of human movement

biomechanics

physics (mechanics) of motion produced by biological systems

• integrates biological characteristics with mechanics

• examines forces acting upon, within, and produced by a body

Mechanics

efforts of forces and energy on the motion of bodies

• statics vs dynamics

Statics

study of systems in a state of equilibrium

• at rest or in constant state of motion

Dynamics

study of systems in a state of changing motion

Kinetics

study of forces that inhibit, cause, facilitate, or modify motion of a body/system

• changing someway to aid motion

Kinematics

study of the spatial and temporal characteristics of motion without considering what’s causing the motion

• space and time

Ergonomics (occupational biomechanics)

Interactions of humans and machines

• attempt to improve human-machine system

• manipulating the work environment to enhance safety

• changing the task to make it compatible with the user’s characteristics

• enhancing the organization of tasks to better accommodate needs of the use

Pedagogy

teaching and coaching used to enhance performance

adapted physical education

process of teaching movement activities to persons with disabilities

Motor Control, Development, & Learning

What are the 3 aspects that motor (movement) behavior is studied?

Motor Control

How nervous system controls coordinated skill performance

• “muscle memory”

• coordination

• depends on open-loop (reflexive) OR close-loop

Motor Development

how motor control changes over time

• voluntary motion begins when the nervous and muscular systems are ready

• starting at birth, body’s in state of dynamic state of change

Motor Learning

How humans learn motor skills

• trial-and-error

• focuses primarily on neurological aspects of attaining and retaining motor skills (muscle memory)

Gentile Model (of motor learning)

1. Initial Stage

• generating a movement pattern to achieve some degree of success

2. Fixation and Diversification

• adapt movement to specific demands of situation

• consistency

• perform with economy of movement

Motor Learning Stages (3)

1. Cognitive

• movements are slow, inefficient, controlled consciously

• trial and error & requires lots of focus

2. Associative

• movements are more fluid, reliable, efficient

• some parts controlled autonomously - in between phases

3. Autonomous

• movements highly accurate, efficient, consistent. Flow state, most/all control is autonomous

System

any structure/organization of related structure whose state of motion is of analytical interest

Anthropometry

describes the shape of the system

• varying body shape & limb proportions affect motion

• measurements: height, weight, volume, proportion, shape

  • BMI (bone density & muscle can alter index)

  • Somatotype

  • Waist-to-hip ratio; Crural Index (tibia to femur ratio); torso to leg

Somatotype (3 types)

used to characterize body types broadly:

1. Endomorph= short & Stour

• hold fat in belly, hard to drop fat in belly

2. Mesomorph= muscular and lean

• hold fat in waist

3. Ectomorph= long and lengthy

• hard to gain muscle- need lots of calories & protein

3 Cardinal Planes

planes that divide body perfectly in half:

• frontal (coronal), sagittal, transverse

plane, axis

MOVEMENTS OCCUR IN A _______ AND AROUND AN ________!!!

Motions in Multiple Planes

• circumduction

• pronation/supination of the ankle

Degrees of Freedom

number of independent ways a system can move (aka # of planes and axis it can move around)

• 6 possible degrees of freedom

• 2 movements (opposite of one another)= 1 DOF

• constraints= cannot move along any axis

center of mass

point that represents the average location of a system’s mass. as we move, center of gravity moves with us

• all 3 carinal planes meet in the middle, passing through this point

• gravitational pull is concentrated here

line of gravity

imaginary vertical line that passes through center of gravity

• gravity’s force is always down

free-body diagram

simplified representation of the system free of the movement environment

discrete skill

movement with a definite beginning and end-point

• ex: baseball pitch

continuous skill

cycles of motion performed repeatedly with no well-defined beginning/end points

• same motion; ex: cycling

Serial skills

movements that appear to be continuous but are really a combination of discrete motions

• ex: triple jump (sprint, leap, then jump and land)

Repeated discrete skill

at the end of the stroke the body is not in position to begin the next stroke

• “recovery phase” is necessary

• ex: rowing

Closed Skill

skill performed under standar environment conditions

• ex: basketball free throw in gym

open skill

skill that must be altered because of changing dynamics of activity, environment, or object of interest

• ex: during a basketball game, no two passes are identical

Translation (linear movement)

motion along one axis in which all points of the system move at the same time, in same direction

• rectilinear translation= path of system is straight line

• curvicular translation= path of system is angled

rotation motion

occurs when the system is restricted to move around a fixed axis- therefore in a circular path

• aka angular motion

• ex: skip-it

General motion

combination of linear and angular motion

concave, convex

If ________ surface is fixed, _______ convex rolls and glides in opposite directions.

• concave-convex rule

convex, concave

When _______ surface (femur) is fixed, _______ surface (tibia) rolls and glides in same direction.

• concave-convex rule

Simple kinetic chain

What kind of kinetic Chain?

each segment participates in no more than 2 linkages

• ex: knee (femur & tibia)

Complex Kinetic Chain

What kind of kinetic Chain?

a segment linked to 2 or more linkages

• ex: sacrum (articulates with L5 vertebrae and 2 hip joints)

• motion at one link affects force transfer and motion at other links

• optimal performance requires efficient sequencing and timing of links (coordination)

Open Kinetic Chain

What kind of kinetic Chain?

the most distal segment is free to move

• ex: leg extension because can move and adjust feet

Closed Kinetic Chain

What kind of kinetic Chain?

most distal segment is stationary

• less mobility, cannot focus on specific muscle/group

Functional Kinetic Chain

What kind of kinetic Chain?

complex chain; some links are open and others are closed kinetic chain

• ex: running

Compensatory Motion

adaptions at normal kinetic chain links resulting from abnormal motion at another link

• ensures certain tasks are performed

• Disadvantages: requires more energy & changes in force patters (pain)