Exam 1 Study Guide PDF

Preview

Summary

Exam 1 Study Guide...

Description

Chapter 1 - What is Biomechanics ●

Biomechanics ○ Bio - life ○ Mechanics - study of actions & forces ■ Statics - branch of mechanics dealing w/ systems in constant state of motion ■ Dynamics - branch of mechanics dealing w/ systems subject acceleration ○ Kinematics - study of description of motion, including space & time ■ Without reference to the forces that cause it ● Form of technique - kinematics of exercise/ sport skill application ○ Kinetics - study of action of forces ○ Kinesiology - study of human movement ○ Sports Medicine - clinical & scientific aspects of sports & exercise

●

Qual vs Quan ○ Quantitative - use of numbers ○ Qualitative - words, nonnumeric description of quality

●

Solving Quantitative Problems 1. Read problem carefully 2. Write down given information 3. Write what is wanted / to be determined 4. Draw diagram 5. Identify/ write down formulas to be used 6. Work it out & solve a. Inference - process of forming deduction from available info

●

Units of Measurement ○ English system - system of weights & measures originally developed in England & used in US today ■ Yard, feet, inches, miles, ounces, lbs, tons, slugs ○ Metric system - S.I. system, system of weights & measures used internationally in scientific applications & adopted for daily use by every major country except US ■ Meter - length ■ Kilogram - mass ■ Second - time ■ Kelvin - temperature ○ Conversions ■ 1 in = 2.54 cm ■ 1 lb = 4.45 N

Ch. 2 - Kinematics Concepts for Analyzing Human Motion ●

Motion ○ General Motion - motion involving translation & rotation simultaneously ● ex) football kicked end over end in air ■ Linear - along line that may be straight or curved, w/ all parts of body moving in same direction @ same speed ● Aka translatory motion or translation ● ex) sleeping passenger on plane ○ Rectilinear - along straight line ■ ex) motorcyclist motionless posture ○ Curvilinear - along curved line ■ ex) skier jump ■ Angular - involving rotation around central line or point ● Axis of rotation - imaginary line perpendicular to plane of rotation & passing thr/ center of rotation ○ ex) front flip ○ Mechanical system ■ System - object / group of objects chosen by analyst for study

●

Terminology ○ Anatomical Reference Position - erect standing position w/ all body parts considered the starting position for body segment movements ○ Cardinal Planes - 3 imaginary perpendicular reference planes that divide body in half by mass ■ Sagittal Plane - anterior posterior plane - plane which forward & backward movements of body occurs ● L & R halves ○ Forward roll, running, marching, bowling & cycling ○ Flexion/extension, hyperextension, plantar/dorsiflexion ■ Frontal Plane - coronal plane - plane which lateral movements of body occurs ● Front & back halves ○ Cartwheel, jumping jacks, side stepping & side kicks ○ Abduction/adduction, lateral flexion, elevation/depression, inversion/eversion, radial/ulnar deviation ■ Transverse plane - horizontal plane - plane which horizontal body movements occur when body in erect standing position ● Top & bottom halves ○ Twist ○ Rotation, supination/pronation, horizontal abduction/adduction ○ Center of mass/gravity - point where 3 cardinal planes intersect ○ Circumduction - flexion/extension, abduction/adduction

●

Spatial Reference System ○ Cartesian Coordinate System - measured in 2 or 3 primary axes ■ 2 dimensional = x,y ■ 3 dimensional = x, y & z

●

Analyzing Human Movement ○ Qualitative analysis requires knowledge of specific biomechanical purpose of movement & ability to detect causes of error ○ 2 main sources of infor for analyst during fine motor skill ■ Kinematics / technique - understand what one is trying to do ■ Performance outcome - observe what really happened ○ Analysts should be able to distinguish cause of problem from symptoms of problem ○ Experience in motor skill does not always translate to proficiency in analyzing skill ○ Repeated observation is useful in helping to distinguish between performance errors & random errors ○ Video camera provides advantages & disadvantages ■ Video & film ■ Accelerometer

Ch. 3 - Kinetic Concepts for Analyzing Human Motion ●

Inertia - tendency of body to resist change in its state of motion ○ Proportional to its mass ■ More mass = more tendency to stay at same state of motion so more difficult to move

●

Mass - quantity of matter combined in object ○ SI = kg, English = slug ■ Not same as weight ● This always stays the same, no matter where one goes

●

Force - push/pull, product of mass & acceleration ○ Characterized by magnitude, direction, point of application ■ F = ma ■ 1 N = (1 kg)(1 m/s^2) - SI system ■ 1 lb = (1 slug)(1 ft/s^2) - english system ○ Free body diagram - sketch shows defined system in isolation w/ all force vectors acting on system ○ Net force - resultant force derived from composition of 2 or more forces ■ 0 = motionless or constant velocity ■ >0 = moving in that direction

●

Center of Gravity - point around which body’s weight is equally balanced, no matter how body is positioned ○ Center of mass ○ Location determines way which body responds to external forces

●

Weight - gravitational force that earth exerts on body ○ W = mg ■ As mass increases so does weight ○ Weight changes based on gravitational forces ○ Newtons

●

Pressure - force per unit of area over which force acts ○ P = F/A ■ Metric system = N/cm^2 & Pascals (Pa) ● Pa = N/m^2 ■ English system = psi → lb/in^2

●

Volume - amount of 3 dimensional space occupied by body ○ Amount space it occupies ■ Width, height, depth ○ Metric system = cm^3, m^3 & L ■ 1 L = 1000 cm^3 ○ English System = in^3, ft^3 & qt ■ 1 qt = 57.75 in^3

●

Density - mass per unit volume ○ D = m/v → kg/m^3 → N/m^3 ■ Specific weight - weight per unit of volume ● lbs/ft^3

●

Torque - rotary effect of force ○ Angular equivalent to linear force ○ T = Fd ■ Greater torque = greater tendency for rotation to occur ○ N-m or ft-lb

●

Impulse - product of force & time over which force acts ○ J = Ft ■ Large change in object can be small force for long time or large force for short time

●

Mechanical Loads on Body ○ Compression - squeezing force ■ Weight of body on spinal column ○ Tension - pulling force that creates tension ○ Shear - force directed parallel to surface ■ Cause one portion of object to slide, displace or shear w/ respect to other object

●

Mechanical Stress - distribution of force w/in body when external force acts ○ F/A ■ Same force on small A produces more stress than on larger A ○ Lumbar vs cervical vertebrae ● Compressive, tensile & shear stress indicate direction of acting stress

●

Torsion, Bending & Combined Loads ○ Bending - asymmetric loading that produces tension on one side of body’s longitudinal axis & compression on the other side ○ Torsion - load producing twisting of body around longitudinal axis ■ Typically when one end of structure is fixed ● ex) torsional fracture of tibia when foot held in place ○ Combined loading - simultaneous action of more than one pure forms of loading ■ Most common type of loading

●

Effects of Loading ○ Acceleration ○ Deformation - change in shape ■ Small loads = elastic ■ Deformation exceeds yield point / elastic limit = plastic deformation ○ Plastic deformation - permanent change in shape ○ Elastic deformation - temporary change in shape

●

Different Loading ○ Repetitive loading - repeated application of subacute load that usually relatively low in magnitude ■ chronic/stress injury, microtrauma ○ Acute loading - application of single force of sufficient magnitude to cause injury ■ Macrotrauma

●

Tools for Measuring Kinetics ○ Force platforms ○ Pressure platforms

●

Vector - physical quantity that possesses both magnitude and direction ○ Represented by arrows ■ Kinetic vector = force, weight, pressure, specific weight & torque ■ Kinematic vector = displacement, velocity & acceleration ○ Scalar - magnitude but no direction ■ Mass, volume, length & speed ○ Vector Composition - process determining single vector from two or more by vector addition ■ Tip to tail ○ Vector Resolution - replaces single vector w/ two perpendicular vectors ■ Resultant vector = original vector...