Lectures 6-10 Flashcards
Starting with
S&C for the junior athlete
Lecture 7
When is childhood?
S&C for the junior athlete
2 years old up until 10-12 years old
What happens to total body mass between the ages of 6-12 years old
(S&C for the junior athlete)
It doubles
Need to find out what SkM is
S&C for the junior athlete
Slide 3, lecture 7
What is adolescents?
When does adolescents end?
(S&C for the junior athlete)
A period of cognitive and physical development between the onset of puberty and attainment of adulthood
18-21 years
What elements cause variation in youth?
S&C for the junior athlete
Growth - increase in size of the body
Maturation - the process of becoming mature
Development - broader concept which includes biological and behavioural
Physical Activity Recommendations for children
S&C for the junior athlete
60 min, 5x per week
3 aerobic sessions
3 resistance training sessions
11,000-15,000 steps per day
Children are double the volume of adults
Focus on “Strength” in junior athletes
S&C for the junior athlete
Increases steadily then sex differences in adolescence
Histochemical / biochemical data is limited for ethical reasons - some data suggests children are more prepared for endurance training and (can’t tell if anaerobic or aerobic, recap) metabolism
Focus on the “conditioning” - cardiorespiratory for junior athlete:
Around what ages sees the most increase, concomitant with increase in muscle mass and strength
(S&C for the junior athlete)
10 years old
Focus on the “conditioning” - cardiorespiratory for junior athlete:
Changes in prepubertal children compared to adults
(S&C for the junior athlete)
See little changes in children compared to adults ~5% increase in CRF in 8 weeks
Focus on the “conditioning” - cardiorespiratory for junior athlete:
Where is the junior athlete typically compared to norms for CRF
(S&C for the junior athlete)
Typically above the norm
What are practical considerations for S&C with junior athletes?
(S&C for the junior athlete)
Safety / suitability of the exercise
Enjoyment
Contact time
Specificity of the sport
Summary slide
S&C for the junior athlete
Slide 20 lecture 7
In earlier years what is the emphasis during exercise?
S&C for the junior athlete
To have fun and move well
What does a coach need to be in order to work with junior athletes?
(S&C for the junior athlete)
Dynamic
Adaptable to both the situation and the athlete
Need to consider multiple factors when working with junior athletes, such as:
(S&C for the junior athlete)
Consider training load, nutrition, injury prevention etc
Is resistance training in young athletes safe?
S&C for the junior athlete
Yes but needs to be programmed by professionals
What is vital when being a coach for junior athletes?
S&C for the junior athlete
Understanding variation in children/adolescent development
For a given level of excitation, muscle force depends on what?
(Force-Velocity Curve)
Muscle length (force length relation - A)
And on the rate of change in length (force-velocity relation - B)
The force velocity relationship is what?
Force-Velocity Curve
It is the observation that muscle force and contraction velocity are inversely related
In shortening (concentric) muscle actions, where contraction velocity is high, muscle force must be what?
(Force-Velocity Curve)
Low
In shortening (concentric) muscle actions, where muscle force is high, contraction velocity must be what?
(Force-Velocity Curve)
Low
How can speed-strength on the force-velocity curve be achieved?
(Force-Velocity Curve)
By training at Lowe percentages of 1 Rep Maximum (RM) therefore resulting in an increase in movement velocity
During shortening contractions (in vitro), the force generated is always “what” compared to isometric contractions (for the same level of muscle activation)
(Force-Velocity Curve)
Lower
The trade-off between force and velocity is thought to occur due to what?
(Force-Velocity Curve)
A decrease in the time available for cross bridges to be formed
More time = more cross bridges
More cross bridges = greater contractile force
How is the force-velocity relationship different with lengthening (eccentric) muscle actions?
(Force-Velocity Curve)
It is the other way round
Where contraction velocity is high, muscle force can be high
Where muscle force is low, contraction velocity must be low
Draw diagrams of
Force-Velocity Curve
Eccentric vs concentric velocity curve
Tip to remember for force-velocity curve with eccentric contraction
(Force-Velocity Curve)
E = elastic properties of muscle (Titin)
Tip to remember for force-velocity curve with concentric contraction
(Force-Velocity Curve)
C = cyclic interaction between myosin cross-bridges and actin filaments within the contractile units of a muscle
How does the control strategy employed by the nervous system during lengthening (eccentric), shortening (concentric) and isometric contractions?
(Force-Velocity Curve)
Lengthening (eccentric) differs from shortening (concentric) and isometric contractions
What happens to spinal and corticospinal excitability during lengthening vs shortening and isometric conctractions
(Force-Velocity Curve)
Excitability is reduced
Work done by Nishikawan et al (2012) suggest about Titin’s involvement in muscle contraction mechanics
(Force-Velocity Curve)
It acts as an internal spring able to store and release elastic potential energy
Positive power can only be produced during what type of contraction?
(Force-Velocity Curve)
Concentric contractions
Equation for Power
Force-Velocity Curve
Power = Force x velocity
Definition of power
Force-Velocity Curve
The ability to exert a maximal Force in as short a time as possible
Look at different points on force-velocity curve
Force-Velocity Curve
E.g. speed strength etc
Lecture 8, slide 32
Recap questions
Force-Velocity Curve
Lecture 8, slide 34
What is maximal muscular power?
Developing muscular power
It is the highest level of power achieved in muscular contractions
What is maximal muscular power often referred to as?
Developing muscular power
The rate of doing work
From an applied perspective, what does maximal power represent?
(Developing muscular power)
The greatest instantaneous power during a single movement performed with the goal of producing maximal velocity at takeoff, release or impact
Research (Slide 3, lecture 9) shows what about maximal power and athletic performance
(Developing muscular power)
Superior ability to generate maximal power typically results in enhanced performance
A fundamental relationship exists between strength and power, which dictates what?
(Developing muscular power)
An individual cannot possess a high level of power without first being relatively strong
3 key elements must be considered when attempting to increase power output, what are they?
(Developing muscular power)
Overall muscular strength is maximised (most important)
Develop ability to express high forces in very short periods of time
Important to develop an ability to express high forces as the velocity of shortening increases
The ability to generate maximal power during a movement is governed by:
(Developing muscular power)
Muscle morphology
Muscle mechanics
Neural factors
Muscle environment
What is muscle morphology?
Developing muscular power
Muscle fibre type Cross sectional area Fascicle length Pennation angle Tendon properties
What is muscle mechanics?
Developing muscular power
Force - length relationship
Force - velocity relationship
Type of muscle action - eccentric, isometric, concentric
What are neural factors?
Developing muscular power
Motor unit recruitment
Firing frequency
Motor unit synchronisation
Inter-muscular coordination
What is the muscle environment?
Developing muscular power
Fatigue
Endocrine / hormonal factors
Muscle temperature
Increased number of motor units recruited, results in what?
Developing muscular power
Increased force
Increased high threshold motor units, results in what?
Developing muscular power
Increased force & RFD (Slide 12, lecture 9 recap)
The force generated by the contraction of a single muscle fibre can be increased how?
(Developing muscular power)
Increased the rate at which muscle action potentials stimulate the muscle fibre
If the interval of time between action potentials is shortened, the muscle fibre does not have time to relax completely between two stimuli, resulting in what?
(Developing muscular power)
A more forceful contraction - this is summation
Definition of summation
Developing muscular power
A process of adding things up, (more action potentials = greater force)
In terms of intermuscular coordination, how does the magnitude and timing of activation of agonists, synergistic and antagonists impact force
(Developing muscular power)
Increased agonists
Increased synergists
Decreased antagonists
Result in -> increased force
In terms of intramuscular coordination, optimal activation patterns within a muscle do what?
(Developing muscular power)
Enhance force production
Strength training vs Power training
Developing muscular power
Is strength training as effective as power training
What do well trained athletes require in order develop maximal power?
(Developing muscular power)
Training programmes that contain specificity and variability
Do previously untrained athletes with low levels of strength training require specific training programmes to develop maximal power?
(Developing muscular power)
No, they display improvements in muscular function that are easily invoked and relatively non-specific from basic training
Typically, both weaker and younger athletes do not possess what in order express high power outputs?
(Developing muscular power)
Requisite strength levels
As weaker and younger athletes aren’t strong enough to get high power outputs, how can power output be increased?
(Developing muscular power)
By simply increasing strength levels
What is the optimum point for strength in terms of power?
Developing muscular power
When an athlete gets to a strength level where costs of further increases in strength outweigh benefits
Once the optimum strength point is reached, what should the focus of training shift to?
(Developing muscular power)
Should shift to other areas to continue adaptation and maintain current strength - specificity
How do you increase power in a relatively weak athlete?
Developing muscular power
Strength training
How do you increase power in relatively strong athletes
Developing muscular power
Power training
Strength maintenance
What is the bottom line of the relationship between power and strength?
(Developing muscular power)
Power is built on a foundation of strength
What is biological age?
S&C for junior athlete
Age of body maturity
Guidelines for adults for physical activity
S&C for junior athlete
150 min moderate activity (broken up into 5X30)
75 min vigorous activity
Guidelines for physical activity for children
S&C for junior athlete
60 min, 5 x per week
3 aerobic sessions
3 resistance training sessions
11,000-15,000 steps per day
Double volume of adults
Name a practical consideration for S&C with junior athletes
(S&C for junior athlete)
Time
Look at force-velocity curve for eccentric contractions
Force-velocity curve
Lecture 8
Where is an isometric contraction on the force-velocity curve?
(Force-velocity curve)
High force
No movement
What is tetanus?
Developing muscular power
Stable contraction in muscle
What is a synergist muscle? (Recap) lecture 9
Developing muscular power
Muscle that helps or allows a movement to happen
Read Cormie (2011)
Lecture 9
How can a muscle be stimulated?
Muscle action
Can be artificially via an electric shock / voluntarily
Types of muscle contraction
Muscle action
Isotonic (dynamic) - eccentric/concentric
Isometric - no movement
Definition of contraction in muscle
Muscle action
When tension is developed in a muscle as a result of a stimulus
“Contraction” can be a confusing term in muscle actions, so what can be used instead to avoid confusion?
(Muscle action)
Muscle actions
What is an isometric contraction?
Muscle action
Where active tension is developed within the muscle but joint angles remain constant
What produces greater force, concentric or isometric contractions?
(Muscle action)
Isometric
What do isotonic contractions involve?
Muscle action
The muscle developing active tension to cause or control joint movement
(Changing length)
What are concentric contractions?
Muscle action
The muscle develops active tension as it shortens
When does a concentric contraction occur?
Muscle action
When a muscle develops enough force to overcome applied resistance
How are concentric contractions described?
Muscle action
As being a positive movement
What are eccentric contractions?
Muscle action
Where the muscle lengthens under active tension?
When does an eccentric contraction occur?
Muscle action
When muscles gradually lessen in tension to control the descent of resistance
(Must be a controlled descending movement)
What is a key take home message from the practical? (Bicep and tricep force’s one)
(Muscle action)
Showed that neural drives in the muscle are different during lengthening vs shortening muscle actions
What are the two characteristics of muscle contraction that the “popping sarcomere hypothesis” are derived from
(Muscle action)
The produced force by eccentric contraction is greater than concentric
The presence of the unstable sarcomere lengthened
What is the unstable sarcomere length part of the popping sarcomere hypothesis?
(Muscle action)
When lengthened, actin & myosin interact less and less and at limit of this, sarcomere is unstable because actin & myosin are no longer engaged and therefore, the structure is at risk of breaking down
What happens at the “X” mark (Slide 10, lecture 6) for popper-half sarcomere?
(Muscle action)
You can initiate some structural instability in the sarcomere, whereby, it can become damaged (permanently/temporarily)
What type of movement is a squat?
Muscle action
A compound movement
What is a compound movement?
Muscle action
Exercises that work multiple muscle groups at the same time
What type of movement is the downwards phase of a squat?
Muscle action
Eccentric
What type of movement is the upwards phase of a squat?
Muscle action
Concentric
During downward phase of squat, what muscles work eccentrically at the:
Hip
Knee
Ankle
(Muscle action)
Gluteus max and hamstring muscles
Quadriceps
Calf muscles, ankle flexors and posterior tibialis
During upward phase of a squat, what muscles work concentrically at the:
Hip
Knee
Ankle
(Muscle action)
Gluteus max and hamstring muscles
Quadriceps
Calf muscles, ankle flexors, posterior tibialis
What is excitation-contraction coupling?
Muscle action
The ability to initiate contraction within the muscle
If you want to do eccentric training, you must first make sure of what?
(Muscle action)
The muscle is developed enough to be able to cope with the excessive strain placed on that muscle during training
How can we examine dynamic exercise using concentric and/or eccentric muscle actions in the laboratory?
(Muscle action)
Using an isokinetic dynamometer
What are isokinetic dynamometers?
Muscle action
Passive devices which resist applied forces and control the speed of exercise at a predetermined rate
What can be “fixed” when using an isokinetic dynamometer?
Muscle action
Speed/velocity of the movement
Muscle contraction (ideally maximal)
What is an agonist muscle?
Muscle action
A muscle responsible for creating movement at a joint
AKA the prime mover
What is an antagonistic muscle?
Muscle action
A muscle that opposes the agonist, providing a resistance for co-ordinated movement
Where are antagonistic muscles located?
Muscle action
On the opposite side of the joint from the agonist
What can antagonistic muscles also be know as?
Muscle action
Contralateral muscles
Synergists?
How do antagonistic muscles work?
Muscle action
In cooperation with agonist muscles by relaxing in order to allow for coordinated movement
Example of antagonistic pair with knee flexion
Muscle action
Quads - antagonist
Hamstrings - agonist
What is co-activation?
Muscle action
A strategy used by the CNS to achieve movement accuracy
How does co-activation work?
Muscle action
Contraction of agonist leads to minor activity in antagonist
When does muscle coactivation occur?
Muscle action
When agonist and antagonist (or synergist) muscles surrounding a joint contract simultaneously to provide joint stability and general motor control
During fatigue, what can happen to general motor control? What can this cause?
(Muscle action)
It breaks down
Instability between pair mismatch and you can damage the muscle
What are stabiliser muscles
Muscle action
Muscles that contract to fixate or stabilise an area to enable another limb to exert force and move
Where are stabiliser muscles?
Muscle action
Surrounding the joint or body part
What can stabiliser muscles also be known as?
Muscle action
Fixators
What are stabiliser muscles essential in doing?
Muscle action
Establishing a relatively firm base for the more distal joints to work from when carrying out movements
Kicking action - important - exam question
Muscle action
Slides 23 & 24
Lecture 6
When kicking a football
What muscles are primarily responsible for hip flexion?
(Muscle action)
Quadriceps
Hip flexors
When kicking a football
Recap other muscle pairings
(Muscle action)
Slide 23 & 24,
Not clear on diagram
Recap questions
Define the terms isometric and isotonic
What are typical examples of eccentric exercise
How can we measure and monitor isolated muscle function
(Muscle action)
Write them down
The football kick will probably be a question in the exam, must recap
(Muscle action)
Slide 23 & 24 lecture 6
Top down approach
Perception-action
Brain down to body
Bottom up approach
Perception action
Body up to brain
What are efferent signals/neurons in the body?
Perception-action
Motor neurons that carry neural impulses away from the CNS and towards the muscle to cause movement
What are afferent signals/neurons in the body?
Perception-action
Sensory neurons that carry nerve impulses from sensory stimuli towards the CNS and Brain
What are the two main parts of agility?
Perception-action
Change of direction speed (physical skills & technical skills)
Cognitive response to sports-specific stimulus (perceptual skills & decision-making skills)
What is key for the transfer of learning?
Perception-action
In situ context specific training
Must be relevant - reaction lights (not good cos you don’t do that in a game) vs real opponents (good cos it’s accurate to the game)
What is important to try and design when creating training for athletes?
(Perception-action)
The information the athletes are attending to
The intention we are encouraging from that information
How do you best develop motor learning?
Perception-action
Through teaching skills (tracking opponents)
Not
Through drills (run to cone then turn)
How must athletes be challenged in a session in order for the best training to occur?
(Perception-action)
Appropriately
Definition of agility
Perception-action
A rapid whole body movement with change of velocity or direction in response to a stimulus
What are mirror neurons related to?
Perception-action
When we watch other people perform skills the parts of the brain activated when performing that skill are activated in the spectator
