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19 Cards in this Set
- Front
- Back
1st Class Lever
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-joint lies between muscle & load
- most efficient - weakest - et. flexing neck & posturing head forward & downward |
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2nd Class Lever
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- load lies between joint & pulling muscle
- strongest - eg. lifting a wheelbarrow |
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3rd Class Lever
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- muscle lies between joint & load
- poor mechanical advantage - most common in body - eg. elbow joint |
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Principle of Stability
(Principles of Biomechanics) |
stable balance requires:
- wide base of support - centre of gravity within base of supporrt - large mass - low centre of gravity |
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Principle of Number of Joints
(Principles of Biomechanics) |
- max force is produced when all joints that can be used are used (allows more muscles to contract)
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Principle of Order of Joints
(Principles of Biomechanics) |
- max velocity is produced when joints are used in order from largest to smallest
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Principle of Impulse
(Principles of Biomechanics) |
- the greater the applied impulse, the greater the increase in velocity
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Principle of Direction
(Principles of Biomechanics) |
- movement occurs in direction opposite to that of an applied force
- for every action, there is an equal & opposite reaction |
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Principle of Angular Motion
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a) angular motion is produced when a force is applied at a distance from centre of gravity or axis of rotation (eg. a diver)
b) angular momentum can be changed by changing the position of extremities in relation to axis of rotation (eg. spinning) |
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Law of Inertia
(Newton's First Law) |
- a body will remain at rest or in a state of constant velocity unless acted upon by an external force
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Law of Acceleration
(Newton's Second Law) |
- F=ma
- relationship between object's mass, its acceleration & applied force - a force applied to a body causes an acceleration & applied force of a magnitude proportional to the force, in the direction of the force, inversely proportional to the body |
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Law of Reaction
(Newton's Third Law) |
- for every action there is an equal & opposite reaction
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Types of motion
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a) linear - movement in a particular direction
b) rotational - movement about an axis; force is off centre, causing rotation |
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Effective Ways to Communicate
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- positive feedback
- plan key words to say - use analogies/symbols - diagnosis - corrections/remediation |
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4-Step Approach
Observation of a Skill |
1) pre-observation planning
2) observations 3) diagnosis 4) corrections/remediation |
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Pre-Observation
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- identify the purpose
1) preliminary movements 2) backswing/recovery 3) force producing 4) critical instant 5) follow-through |
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Observation Plan
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1. identify observation task & select relevant features
2. appropriate observation strategies 3. number of observations required 4. positioning strategies |
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Primary Error
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- main problem
- should be corrected |
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Secondary Error
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- provide information about primary errors
- result of primary errors - cannot attempt to correct a secondary error without looking at primary error |