Biomechanics revision Flashcards
Motor skill definition
A motor skill is a voluntary, goal-directed activity that is learnt through practice and experience. They are a type of skill that requires movement of the body or limbs to achieve a goal.
What are motor-skills classified under?
Movement precision
Type of movement
Predictability of movement
What are the 2 types of movement precision motor skills?
Gross motor skills
Fine motor skills
What are gross motor skills and an example?
Gross motor skills are motor skills that involve the recruitment of large muscle groups and do not have a focus on precision. For example, running.
What are fine motor skills and an example?
Motor skills that involve the recruitment of smaller muscle groups and are used in movements requiring precisions, such as throwing a dart
What are the 3 types of ‘type of movement motor skills’?
Discrete motor skills
Serial motor skills
Continuous motor skills
What are discrete motor skills and an example?
Motor skills that have an obvious beginning and end, like kicking a football.
What are serial motor skills and an example?
Refers to multiple discrete motor skills being completed in one sequence, such as a gymnastics floor routine.
What are continuous motor skills and an example?
Motor skills that have no definitive beginning and end, like walking.
What are the 2 types of ‘predictability of movement motor skills’?
Closed
Open
What is a closed motor skill and an example?
Is a movement that is self-paced and is in a predictable environment that the individual has large control over. Eg; throwing darts
What is an open motor skill and an example?
Is a movement that is externally paced and is in unpredictable conditions/environment, such as surfing.
What are the 3 stages of learning?
Cognitive
Associative
Autonomous
What is the link between motor skill development, participation and performance?
Those who participate in sport more and more likely to develop their motor skills and therefore perform better. By performing better, they will probably find more enjoyment in the sport and hence, be more likely to continue to participate it, again improving their motor skills, improving their performance and so on.
What are the 4 main principles of a qualitative movement analysis?
Preparation
Observation
Evaluation
Error correction
How is a QMA test reliable?
The test must reproduce similar results when conducted under similar conditions, contexts and situations.
How is a QMA test valid?
The test’s capacity must measure what it is intended to measure. For example, if a test is designed to measure height of jump, it shouldn’t worry about speed of run up.
What are constraints?
Constraints are boundaries that shape a learners self-organising movement patterns, cognitions and decision making process. They influence the way people process information, make decisions and move.
3 types of constraints
Individual constraints
Environmental constraints
Task constraints
Individual constraints examples
Body size (height and weight)
Fitness level
Mental skills
Decision making skills
Environmental constraints examples
Where a player was raised Weather conditions Quality of facilities Cultural norms of community (eg; Australians play AFL but if you grew up in USA you are unlikely to play it compared to Aus) Peer groups Sport club culture Social expectations
Task constraints examples
Rules of sport
Equipment used
Player numbers
Ground dimensions
What does the preparation stage of a QMA involve?
Developing an observation strategy based on knowledge of the game and characteristics of skills in the sport.
Determining the purpose of the analysis
Determining the player to be observed, the focus and how the player will be monitored
What does the QMA observation stage involve?
Recording and live-analyzing a player’s performance.
Also observing team dynamics, if team sticks to gameplan and the opponents pattern of play.
What does the QMA evaluation stage involve?
Judging quality of performance
Deciding the problems of the performance, what caused it and how it can be addressed.
Describe the cognitive stage of learning
Beginner stage of learning where the person is mentally trying to comprehend movement requirements of the motor skill.
Learning characteristics of cognitive stage
Learner asks lots of questions
Movements will be stiff and unrelaxed
Poor error detection and correction abilities
Coaching considerations for cognitive learners
Don’t overload info
Repeating skill in same task is key to development
Describe the associative stage of learning
Intermediate stage where learner is beginning to refine their technique and pattern of skills
Learning characteristics of associative stage
Increased consistency and fewer errors
Better error correction and detection abilities
Can focus on external stimuli, like defenders, while performing skill
Describe the autonomous stage of learning
Advanced/elite stage where skill is largely automatic and the learner does not have to think about skill to do it.
Learning characteristics of autonomous stage
Only small room for growth/improvement
Small variance in performance
Coaching considerations for associative stage
Introduce external stimuli
Coaching considerations for autonomous stage
Offering precise feedback
Biomechanics definition
The science of living things from a mechanical perspective
Force definition
A push or pull
How does force affect objects?
Changes the shape of object
Moves the object
Force equation
Force = mass x acceleration
What is the difference between mass and weight?
Mass is the amount of matter in an object while weight is the force exerted on an object by gravity.
What does Newton’s 3rd Law state?
Newton’s 3rd Law states: for every action there is an equal and opposite reaction
General motion definition
Refers to a complex combination of movements, such as running (many parts working together to move a body in a direction)
What is projectile motion?
Refers to when an object is launched into the air and is only affected by forces of gravity and air resistance.
What are examples of projectiles in sport?
A ball that has been kicked in foopy
Hitting a shuttlecock in badminton
Throwing a javelin
What components influence the flight path of a projectile?
Vertical and horizontal components
What is the vertical component of a projectile affected by?
Gravity
Initial projection velocity/speed
What is the horizontal component of a projectile affected by?
Air resistance
What factors affect the path of a projectile?
Height of release
Speed of release
Angles of release
What is the optimal angle of release for maximal distance?
45 degrees
What is the optimal speed of release for maximal distance?
Maximal speed
What is the optimal height of release for maximal distance?
Maximal height
What are the 3 types of levers?
1st class lever 2nd class lever 3rd class lever
What is an example of a 1st class lever?
Seesaw
Extending head
What is an example of a 2nd class lever?
Wheelbarrow
Standing on tip-toes
What is an example of a 3rd class lever
Flexing elbow (bicep curls, throwing a ball)
What are 4 types of feedback?
Intrinsic feedback
Augmented feedback
Knowledge of results
Knowledge of performance
What is intrinsic feedback?
Intrinsic feedback is when performers use their own senses to assess their performance using visual, auditory, proprioception and touch feedback.
What is augmented feedback?
When coaches provide feedback on how to improve/correct errors that the performer may not know how to do themself.
What is knowledge of results?
Refers to specific feedback about the outcome of the task.
What is knowledge of performance?
Refers to the advice given on how to improve skills being used in performance of a task.
3 purposes of external feedback
Fixing errors
Motivation
Reinforcement
Mechanical advantage of a 2nd class lever
Allows a person to lift heavier objects with less effort
Mechanical advantage of a 3rd class lever
Longer range of motion allows for greater generation of velocity, but will require more force to overcome the inertia.
What are the 2 types of coaching?
Direct coaching
Constraints-based coaching
What is direct coaching?
Rigid coaching that provides feedback on every practice attempt, largely about techniques
What is constraints based coaching?
When coaches use boundaries or place restrictions on the learner.
What are some benefits of constraints based coaching?
Develops active problem solving
Better transfer of skills to in-game
Makes practice more interesting, keeps learner engaged
What is perception action coupling?
Describes the reciprocal relationship between what the performer sees and action they take. The performers perception will influence their actions and vice versa.
Social factors that affect motor skill development
Family Time Self-belief/perceived competency Role models Access to equipment/facilities
Cultural factors that affect motor skill development
Education
Geographic location
Values
Attitude
What is summation of momentum?
Refers to the sequential transfer of momentum from larger body parts closer to the body’s center of gravity to smaller body parts further away from the center of gravity. As a result of summation of momentum, an object that is thrown, kicked or hit can be released/struck at maximal velocity.
Inertia definition
Refers to the tendency for a body to resist a change in its state of motion, whether that state is rest or constant velocity.
How does one change an objects motion?
By applying more force than inertia
Momentum definition
Momentum is a measure of the amount of motion an object has and its resistance to changing that motion.
Momentum equation
Momentum = mass x velocity
How much momentum does a still object have?
Zero
Two objects collide. What one continues in the direction it was going?
The one with greater momentum
State Newton’s 1st Law and an example.
Newton’s 1st law states that a body will remain at rest or in constant motion in a straight line unless acted upon by an external force. For example, a soccer ball will not move on a flat pitch unless it is kicked by a boot (external force).
What is linear motion?
Linear motion is the movement of a body along a straight or curved path where all parts move in the same direction at the same speed.
What is the difference between distance and displacement?
Distance refers to the total path travelled from start to finish, regardless of direction whereas displacement refers to the change of position from initial start point to final end point.
What is the difference between speed and velocity?
Speed is how fast something travels whereas velocity is how fast something changes position
Acceleration definition
Refers to a change in velocity in a given period of time.
What is angular motion?
Component of general motion that involves rotation around a central axis/fixed point. Eg; foot rotating around ankle axis during running (general motion)
What is an internal axis of rotation?
Joints in the body
What is an external axis of rotation?
A body’s center of gravity.
What is torque?
An object’s tendency to rotate
Torque equation
Torque = force x length of lever arm
What is angular distance?
Refers to the sum of all of the angular changes the body undergoes in a movement. For example, a double somersault = 720 degrees total angular distance travelled.
What is angular displacement
Refers to the difference between initial angle of position and final angle of position.
Angular speed equation
Angular distance covered/time
Angular velocity equation
Angular displacement covered/time
Angular acceleration definition
How fast a body changes its angular position
State Newton’s 2nd Law and an example
Newton’s 2nd Law states that a force applied to an object will produce a change in motion in the direction of the applied force proportional to the size of the force
Define moment of inertia
Refers to an object’s resistance to change in angular motion
Moment of inertia equation
Moment of inertia = mass x radius2
Linear velocity equation
Linear velocity = radius of rotation x angular velocity
Impulse definition
Impulse is the change in momentum of an object
Impulse equation
force x time
What is the principle of conservation of momentum?
The principle of conservation of momentum states that the total momentum before a collision is equal to the total momentum after a collision.
Real life example of conservation of momentum
A hockey stick hits a resting puck. The total momentum of both the hockey stick and puck before the collision is the same as after the collision as the momentum from the stick is transferred onto the puck and vice versa. The stick stops moving afterwards, meaning the momentum is zero, like the pucks was, and the puck moves in proportion to the size of the sticks force, meaning the momentum it now moves with is the same momentum as the stick did.
4 factors that should be considered when choosing practice models
- Part or whole practice
- Amount of practice
- Distribution of practice
- Variability of practice
What is part practice?
Learning a skill by separating it into different segments and learning each one at a time. Eg; learning how to serve in tennis, start with ball toss, then racquet raise, then follow through, rather than all at once.
Who would benefit from part practice?
Cognitive learners as it prevents them from being overloaded with information.
What is whole practice?
Learning a skill and its segments all at once.
Types of distribution of practice
Distributed practice
Massed practice
What is distributed practice?
Involves shorter, but more frequent, training sessions. It also includes longer rest breaks between tasks as practice is often performed at a higher intensity.
What is massed practice?
Involves longer, but less frequent, training sessions. It includes shorter rest breaks between tasks.
What type of athlete uses distributed practice?
Often used for full-time professional teams.
What type of athlete uses massed practice?
Often used for non-professional/casual teams, as training needs to be scheduled around other commitments such as school, work etc.
Types of variability of practice
Blocked
Random
What is blocked practice?
Blocked practice refers to practicing the same skill continuously without changing to a different task.
What is random practice?
Random practice refers to varied sequencing of different motor skills in the same training session.
What practice variability is better suited for cognitive learners?
Blocked practice as they are still trying to understand the skill, so conditions should be as stable as possible, which blocked practice allows for.
What is friction?
Friction is what opposes the motion of an object.
What is drag force and where does it occur?
Drag force is a force that opposes the direction of motion of an object, slowing it down. It occurs in water and air environments.
Equilibrium definition
Equilibrium is when all forces and torque are balanced.
What are the 2 types of equilibrium?
Static
Dynamic
What is static equilibrium?
Refers to when an object is not moving/rotating and the sum of their force and torque equals zero.
What is dynamic equilibrium?
Is when an object is moving with constant velocity.
Stability definition
The resistance to the disruption of equilibrium
Balance definition
Ability to control equilibrium
4 factors that affect stability
Base of support
Center of gravity
Body mass
Friction between surfaces
How can stability be increased?
Increasing size of base of support
Lowering center of gravity
Ensuring line of gravity falls within base of support, not in front or behind it
Increase friction between surfaces
Extending base of support in direction of oncoming force (placing foot forward)
