Mech. Principles test 3 Flashcards
6 phases of analyzing sport skills
1) determine the obectives of the skill
2) Note any special characteristics of the skill- rep. non rep. Closed/open
3) Watch elite athletes perform skills
4) divide skill into phases
5) Divide each phase into key elements
6) Understnading the mechanical reason for key elements
Nonrepetitive skills
discrete skills
Shifts from one skill to another- swing bat then run
follow through is a deceleration phase
builds momentum from one skill to the next-tumbling
teach each skill separately
add additional skills and teach the rhythm and patterns when combining multiple skills
Repetitive skills
skill is continuously repeated,
one complete cycle of skill leads to the next
Swimming
Closed skills
skills that are perfomred under predictable environments
No opponent
same required action/movement every time
Easier to train for because you can create a practice environmnent that is the same as comp.
Shooting a free throw, weight lifting-comp.
Open skills
skills performed in unpredictable environments
opponent attempts to foild your physical objective
Basketball game
pitches are dif every time in game
Phases of skills
prepatory movements and mental set phase
windup/backswing
force-producing movement phase- summation of force
follow through phase
Prepatory movements and mental set phase
setting/aligning body before the start of the movement
Does not occur as much in rep. skills
Windup/backswing phase
using antagonistic muscles to windup or make use of the stretch shortening cycle prior to the force producing movement phase
pulling arms back before throwing ball
force-producing movement phase
actual movement of the skill
forward movement of the arm during overhand throw
Makes use of agonist muscles used during concentric muscle action
summation of force
sum of all muscle action produce end result regarding power output
follow through phase
deceleration phase/ braking phase
Occurs immediately following force-producing phase
Antagonist muscles eccentrically contract to slow down motion
during rep. skills this phase is shortened to hasten the recovery phase
5 steps for identifying and correcting errors in sport skills
observe the complete skill
analyze each phase and its key elements
use your knowledge of sport mechanics in your analysis
select errors to be corrected
decide on appropriate methods for the correction of errors
What is the main goal of observing the complete skill
get overall impression of athlete’s performance
What should you be doing when observing the complete skill of an athlete
looking for cues beyond the athlete- flight path, rebound, skate marks
and listening for cues- slapping noise on volleyball
two ways to approach analyzing each phase and its key elements
start with the result
observe each phase of the skill in sequence
What does observing each phase of the skill in sequence entail-steps
preparatory- stance, weight, distribution, head position
backswing- weight transfer, position of implement, flexibility
Force production- approach/actual movement
Follow- through- notice implement immediately afterward, arm and hand action
What should you assess while using your knowledge of sport mechanics while analyzing
assess mechanical efficiency
Gravity, friction, drag, air resistance, opposition forces
What happens to a spin when you decrease rotary resistance?
spins faster
Steps in error correction
separate the phase that contains the error
break the phase into key elements
design a practice/activity useful for teaching correct movement
perform movement slowly, noting key body positions
increase speed, put back into phase
attempt complete skill
What is stride length?
amount of forward reaction force from the earth as one pushes back against the earth
What is stride frequency?
number of strides per unit of time
how do sprinters decrease rotational inertia?
via flexing arms and legs
what do sprinters and long distance runners do to muscles not involved in movement?
they relax them
What do tense muscles do?
increase metabolic demand and can restrict muscle action
In swimming, what is stroke length?
distance each stroke pulls or pushes the water
In jumping, what happens when you thrust greater against the earth?
you have a greater propulsion from earth
What is the order of kinetic whip?
first larger muscles generate momentum by overcoming inertia of larger body masses via pushing off of the earth
momentum is passed on to smaller muscles
What must you have to make kinetic whip work?
windup/backswing
When spinning, what happens when you pull legs and arms in? Why?
angular velocity is increased becasue rotational inertia is decreased
What is arrresting motion? and ex
When two or more objects collide
catching, landing, slowing down, and stopping
Angular momentum equation
decreased RI X increased angular velocity
