PE Studies Semester 1 Exam Flashcards
What is the structure of a skeletal muscle?
- Muscle is made up of several fascicles
- These fascicles contain muscle fibres
- Muscle fibres contain myofibrils
- Along the length of myofibrils are contractile units
called sarcomeres, which contain myofilaments actin
and myosin
What are the three layers of connective tissue?
Epimysium (largest, around the muscle belly)
Perimysium (middle sized, around the fascicle)
Endomysium (smallest, around individual muscle fibre)
Explain the Sliding Filament Theory
Calcium is released into the muscle which prompts a reaction in each muscle fibres between myosin and actin.
Cross bridges are formed which connect myosin and actin and pulls the actin along the myosin, which contracts the muscle.
When contracted, the z-lines of the sarcomere come closer together and the H-zone gets smaller.
The actin and myosin filaments almost fully overlap when in a fully contracted position.
Once contraction finishes, actin and myosin return to their original relaxed position.
Describe how messages are sent to your CNS then to your body to produce movement.
The sensory neurons receive impulses from the sensory receptors and this impulse is then sent from the sensory neurons to the central nervous system (brain and spinal cord).
Motor neurons then receive the impulse from the brain and send it to the muscles to produce the desired outcome.
What parts make up a neuron and what are their functions?
Axon
Nerve impulse travels down axon
Dendrites
Branch off and receive messages which are carried into the cell body
Cell body
Process stimulus and send signals to axon
Motor end plate
Synapse between a nerve and a muscle
Describe action potential
Action potential is the rapid depolarization and repolarisation of an axon to move a nerve impulse along it.
For a nerve impulse to travel down the axon, the threshold potential must be reached, which causes action potential to occur and the nerve impulse can be carried down the axon.
If the threshold potential isn’t reached, nothing happens, which is called the All or None Principle.
Once it has reached the threshold potential, the cell depolarizes and action potential occurs, which sends the impulse down the axon.
The cell then rapidly repolarizes so that the neuron can be stimulated again.
The period in which the nerve cell is waiting to be stimulated again is called the Refractory Period
What are three types of muscular contractions?
Isotonic
Change in length of a muscle performed against a CONSTANT load
[Concentric]
Muscle shortens
(going up in bicep curl)
[Eccentric]
Muscular contraction where muscle lengthens.
Isokinetic
Change in length of muscle performed against a VARYING load
Isometric
NO CHANGE in muscle length
E.g. bridge/plank
Describe the force-velocity relationship
Inverse relationship - as muscle velocity decreases, more cross-bridges have time to attach and consequently the muscle can generate more force.
Concentric = more force –> less velocity
Eccentric = more force resisted –> more velocity
Draw the force - velocity graph for a concentric contraction
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Draw a force-velocity graph for a eccentric contraction
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Draw the force-velocity curve
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Draw the length-tension graph
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Describe the type 1 muscle fibre type
Slow twitch fibres
Endurance based activities
Aerobic ATP production
High capacity for ATP production - generates ATP using aerobic system
Fatigue resistant
Low glycolytic capacity
Glycogen and fat are major fuel source
Increased number of blood capillaries delivers more blood and therefore oxygen to muscle
e.g. marathon
Describe type 2A muscle fibres
Intermediate speed of contraction (faster than type I but slower than type II B)
Team sports, speed endurance activities
moderate fatigue rate
fast contraction rate
Can develop aerobic characteristics with training
Creatine phosphate and glycogen are main fuel source
e.g. 800m r
Describe type 2B muscle fibre
Fast speed of contraction
Explosive movements - very fast contraction rate
Purely anaerobic activities
fast fatigue rate
E.g. sprinting
What is Newton’s 1st law
- An object at rest will remain at rest and a moving object will remain in motion unless acted upon by an external force
What is Newton’s 2nd law
The greater the force applied to an object, the greater the acceleration
What is Newton’s 3rd law
For every action there is an equal and opposite reaction
Describe conservation of momentum
When a collision occurs after striking a ball, the total momentum before the collision should be equal to the momentum after the collision
E.g. momentum generated by a golf club is conserved when transferred onto the ball, but because ball has lower mass, it will move faster
Describe the coefficient of restitution
Measures the elasticity of collision between an object and a given surface
COR of 1 is a perfectly elastic collision (e.g. when ball is dropped from a given height and rebounds back to the height after colliding with the ground
COR of 0 is a perfectly inelastic collision (e.g. ball doesn’t bounce when dropped, playdough)
Name the factors affecting COR
- Equipment and material
- Condition of balls
- Type of equipment being used
- Type and condition of playing surface - Temperature of balls
- Increase in temperature results in increase in COR - Velocity of collision
Describe moment of inertia in relation to a diver diving
Angular momentum stays constant as no external forces are affecting athlete as they are in air
Moment of Inertia is large at the start as diver is in an open body position and body mass is further away from the axis of rotation, decreasing angular velocity
Moment of Inertia decreases as body mass is tucked in and closer to axis of rotation, which speeds up angular velocity
Relationship between MOI and AV is inverse
Draw impulse-momentum relationship graph
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Draw the three types of levers and give examples of them in the human body
- Neck
- lower leg on tippy toes
- arm
What gives a lever a mechanical advantage
A lever will have a mechanical advantage advantage if it has a larger force arm
By making the force arm longer than the resistance arm, the force applied is increase
Describe three factors affecting levers
- Length of levers
- Longer the lever, greater the velocity on impact - Inertia of the lever
- Longer the lever, the heavier it usually is and therefore more difficult to rotate
- By an athlete moving their hands further down the club, athletes can reduce their rotational inertia and therefore make it easier to swing the club - Amount of force
- Amount of force an athlete can generate via muscles determines length of lever athlete should use
- Longer lever is → more force required to move it
= Longer lever is → more
Define torque
Turning effect created as a result of an eccentric force being applied around a pivot or axis
Give an example of torque in sport
Wheelchair basketball - turning wheel to produce movement
Name factors affecting fluid resistance
- Density
- The more dense a fluid is, the more disturbed the fluid becomes and hence the greater resistance - Viscosity
- The more viscous a fluid is (the ‘thickness’ of a fluid, e.g. lava, syrup)
Describe surface drag
The interaction between body surface and fluid
Factors affecting surface drag: body surface area, viscosity, fluid temperature, velocity of object
E.g. wearing swimming caps, tight swimming suit
Describe profile drag
Profile
When a body moves through a fluid medium with sufficient velocity it creates a pocket of turbulence behind the body, an imbalance in the pressure surrounding the body is created (high pressure to low pressure)
Factors affecting profile drag: velocity of the body, surface of body area
Factors reducing profile drag:
Shape
Smoothness
Aerodynamic position
Describe wave drag
The resistance created by the generation of waves where two different fluids like air and water meet
Factors affecting wave drag: greater up and down motion, increased swimming speed
Describe boundary layer separation on a rough surface
High pressure at front
Rough surface causes boundary layer separation to take place later
This causes a smaller pressure differential between the front and the back of the ball as there is only a small pocket of turbulent flow at the rear of the ball
Describe boundary layer separation on a smooth surface
A smooth surface causes boundary layer separation to take place earlier
This causes a larger pressure differential between the front and the back of the ball as there now a large pocket of turbulent flow at the back of the ball
Name 2 factors affecting boundary layer separation
- Velocity
2. Surface roughness
Name factors affecting drag
Speed
Surface roughness
Mass
Shape
Name environmental factors affecting drag
Air density
Atmospheric pressure
Humidity
temperature
Define lift
Refers to the component of force that acts perpendicular to the direction of flow
Define and describe Bernoulli’s Principle’s relationship
States that as velocity of a fluid increases, the pressure the fluid exerts on an object decreases
Bernouilli’s principle helps keep a airplane in the air
Shape of the wing creates an area of high pressure underneath the wing and low pressure above the wing, resulting in upward lift
Define the magnus effect
Term used to describe the effect of rotation on an object’s path as it moves through fluid
- can result in spin
Draw top spin affecting a ball and describe it
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Ball drops, at top of ball the boundary layer is in the opposite direction to oncoming air flow resulting in low velocity and high pressure
opposite on bottom of ball
Draw back spin affecting a ball and describe it
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Spin causes ball to stay in the air for longer due to high pressure at the bottom of the ball
Because boundary layer is traveling in same direction as oncoming air flow at top of ball, this results in higher pressure at bottom of the ball, allowing it to stay in air longer
Draw effect of spin on trajectory of ball
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Name biomechanics principles
Summation of velocity balance force-motion impulse inertia/MOI coordination continuum
What are two types of team cohesion?
- Task cohesion
2. Social cohesion
Describe Carron’s model of group cohesion
PELT
- Personal factors
Refers to individual characteristics of group members, e.g. motives - Environment factors
Refers to the normative forces that bring and hold a group together
E.g. contract, family expectations, geographical limitation - Leadership factors
Refers to the leadership style and how this affects the dynamics of the group - Team factors
Relates to the characteristics of the team, including team stability, prior successes and failures
3 methods a coach can use to improve task cohesion
- communicate clearly/regularly so all members understand their roles
- having clear expectations
- make clear what each individual must do for team to achieve goals
3 methods a coach can use to improve social cohesion
- encourage social interactions away from the sport
- maintain open/honest communication
- resolve conflicts quickly
What are three ways of measuring group cohesion?
- Questionnaires
- Sociograms
- Observations
Describe what a sociogram does
Shows interrelationship between individuals in a team
Can determine potential leaders, cliques, conflict
Popular players are potential leaders
Cliques need to be sorted out as can lead to exclusion/favouritism
what is social loafing / ringelmann effect
Is when individuals reduce their efforts when performing in a group and hide their lack of effort amongst the effort of other group members
How can social loafing be reduced?
- punish group for poor performance
- ensure people understand their efforts are necessary for successful outcome
- reduce group size
- develop cohesive group
- make each task meaningful to those performing it
What 4 components contribute to overall athletic performance
Tactical skills
Technical skills
Physiological preparation
Physiological skills
What is choking in terms of sport
suboptimal performance under pressure
→ a poorer performance compared to if you weren’t under pressure
Describe how you can use mental strategies to improve self confidence (GRIPS)
Goal setting: realistic but challenging goals will increase athlete’s self confidence as goals are completed
Relaxation: athletes who are mentally fresh/relaxed will increase self confidence as are more focused
Imagery: picturing themselves performing the skill perfectly and achieving the desired outcome will increase self confidence
Performance routines: player who performs a set routine for a skill will increase self-confidence, they know they can do the skill under pressure → increases self confidence
Self-talk: positive self talk increases chances of success as they believe in themselves more
Describe how you can use mental strategies to improve concentration (GRIPS)
Goal Setting: Setting goals enable a performer to concentrate on a particular aspect of their performance
Relaxation: Over aroused performers have a narrow focus and this limits their ability to concentrate on relevant cues in the environment. Relaxation techniques help performers maintain concentration on relevant cues thereby improving performance.
Imagery: Imagery used to focus on a particular skill, aspect of a skill or a specific game scenario e.g. a set play.
Performance routines: Performance routines can help athlete to focus on relevant cues in the environment and ignore irrelevant cues which would detract from performance.
Self-talk: Athletes can use key terms to help maintain their concentration or to change their level of concentration. E.g. “focus”
Describe arousal
Mental, emotional, physiological state that prepares your body for action
Advance player needs high arousal to perform optimally, vice versa
Draw inverted U hypothesis
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Describe how you can use mental strategies to improve arousal (GRIPS)
Goal setting: Setting goals help athlete perform at optimal level, having realistic goals to strive for help increase arousal and performance level
Relaxation: Appropriate relaxation methods can reduce arousal e.g. meditation, breathing control
Imagery: Arousal can be increased by creating image of aggressive performance and decreased by thinking of a relaxed performance
Performance routines: Can increase arousal of athlete who uses a set routine, can also decrease arousal through routines like listening to calming music before game
Self-talk: Saying phrases to yourself like ‘keep going’ and ‘you got this’ can increase arousal during a game
Describe how you can use mental strategies to improve motivation (GRIPS)
Goal setting: Setting challenging but realistic goals can increase a players motivation as they are challenged to complete them and aren’t too easy or unrealistic
Relaxation: Being over motivated can experience decline in performance and choke as they are trying too hard to achieve optimal performance. Relaxation methods can help over motivated athletes control their thoughts and focus
Imagery: Can motivate athlete by imagining themselves succeeding at a high level
Performance routine: An athletes intrinsic motivation and desire to perform well can be heightened by their performance routine
Self-talk: Can increase motivation by saying things like ‘you need to work harder if you want to stay in this team’
Describe how you can use mental strategies to improve stress (GRIPS)
Goal setting: Realistic but challenging goals can promote stress in a positive way and improves performance
Relaxation: Athletes can use relaxation techniques to go into an optimum state of mind before a game and reduce stress
Imagery: Can reduce stress by athlete imagining themselves performing skill perfectly
Performance routine: Athletes can use routines to focus on their task at hand instead of worrying about the possible outcomes of their actions
Self-talk: Can be used to reduce stress before or during performance → ‘calm down’
