Chapter 10 Flashcards
quantitative analysis
using high tech instrumentation
usually intended for researchers
measuring variables to optimize athletic preformance
foot forces on sprinters starting block (force platforms)
muscle contraction sequence during running (EMG)
3-D body segment movements during a high jump (motion capture)
qualitative analysis
using sight and hearing
usually done by coaches and teacher
who typically do not have access to complex equipment or specialized knowledge
to identify and correct errors “observe, analyze and correct
requires framework and a set of principals
kinematics
describing human motion without its focus focusing on motion spatial and timing characteristics measurements: position displacement velocity acceleration measured with respect to time linear or angular
kinetics
describing forces leading to motion internal forces: -muscles pulling on bones -bone on bone, inside joints external forces: -acting on the body -without contact from contact with ground opponent or equipment
models of human motion
understanding and observing human movements is complex
all body tissues undergo shape deformation - must make assumptions and qaulifications
most movements occur in three dimensions - but can simplify analysis based on our understanding of the movement
3 models simplify the study of human movement:
particle model
stick figure model
rigid body segment model
particle model
dot represents center of mass
used when body or object is airborne and in flight
projectile motion
stick figure model
body segments= sticks
used when body in contect with other objects
describe gross motor skills in 2-D
rigid body segment model
body segments= irregular 3-D volume
used for sophisticated 3-D analysis
can include shape deformation of body segments
mass
reluctance of an object to chnange state of linear motion
a measure of linear inertia
moment of inertia
relectance of roatating bpdy to change state of angular motion
depends on mass and its ditrubtion around axis of rotation
gravity
force of attraction betwen two bodies
newtons univeral law of gravitation
mass is a measure of ? and is measured in
inertia and kg
weight is a measure of ? and is measured in
force of gravity and newtons
types of motion
linear motion translation
angular motion rotation
general motion
linear motion
all body parts move same distance and direction at the same time
translation: linear motion of the whole body
ex) bobsled
angular motion
body moves on a circular path and rotates about axis of rotation
body segments rotate about their joints
ex) twisting somersault
general motion
body segments move lineraly and rotate at the same time
true for most ahtlete and every
ex)
how do levers work
force is applied and if the turning effect if the force is greater than the resistance
then: roatation at the axis/fulcrum occurs
to determine turning effect, consider the length of force arm and resistance arm
when lever rotate around and axis/fuldrum:
movement of force or torque is produced
what movement of force occurs?
torque = force arm x force
therefor: the longer the force arm:
less force is needed
greater torque is produced
types of levers
levers preform different functions three basic types first class second class third class differ based mechanics and how these compnetns are positioned -axis -resistance -force
first class levers
applied force and resistance on opposite side of axis at un/equal distance from one another
ex) crow bar
human: head flexion
second class levers
applied force and resistance on same side of axis; resistance closer to axis
ex) wheel barrow
human: rare: toe raise
third class levers
applied force and ristsenace on same side os axis; closer to the axis
ex) fishing
human: many: forearm flextion
surface drag
laminar flow: small, streamlined, smooth, slow-moving bodies
smooth, layered flow pattern with no disturbances
turbulent flow: most human activities
distured flow pattern that changes flow conditions
magnus effect
a rotating body carries boundary kayer that interacts with surrounding air
boundary layer flow opposite to relative airflow
-air is slowed by friction
-zone of increased pressure created
bonadry layer same as realtive airflow
-air is not slowed down
-zone of decreased pressure created
net difference in pressure on opposite sides of roating obect = magnus force
found is ping pong, tennis, soccer, baseball
