Ch 19 Part 1 Flashcards
What are the 3 important aspects of physical performance for Athlete Development?
- Speed
- Change of Direction
- Agility
What does speed require
the ability to accelerate & reach maximal velocity
Change of direction is the physical capacity to __________ while _____ & then ____, sometimes using a different ____ of travel
change direction; decelerating; reaccelerating; mode
What does agility require
The use of perceptual-cognitive ability in combination with change-of-direction ability
What are the 2 things can human locomotion can be categorized as within sport
- Linear
- Multidirectional
What can be classified as linear
- Sprinting
- Track and Field events
- Game-based contexts (open-field running)
What can be classified as Multidirectional
- Team sports
- Changes of direction predominate
What limits speed, change of direction, & agility?
The effective application of force
Which factors affect an athlete’s success in the explosive movements involved in speed, change of direction & agility?
- Athlete’s strength capacity
- Athlete’s ability to use this strength within the constraints of the activity
What are the 2 variables that describe force relative to the time available to produce force?
- Rate if Force Development (RFD)
- Impulse
What is the rate of force development
The development of maximal force in minimal time
What is the RFD typically used as
As an index of explosive strength
How can RFD be described as in terms of an equation
change in force divided buy the change in time
In performance of Functional Movements how long is force typically applied for?
0.1 to 0.2 seconds
How much time would Absolute Maximum force Development require?
0.6 to 0.8 seconds
Define impulse
The change in momentum resulting from a force, where momentum = mass x velocity
What is impulse measured as
The area under the force-time curve
Where do we want to move the force-time curve up to
Up tp the left
In which phases do athletes attempting to increase speed apply force to the running surface over a period of time?
In the stance phase of sprinting or in the plant phase of changing direction
What do changes in impulse result in
Changes in the athlete’s momentum & therefore the ability to either accelerate or decelerate
Braking phase horizontal and vertical force
negative horizontal force
positive vertical force
Propulsive phase
positive horizontal force
positive vertical fore
What type of production of force occurs during the maximal velocity phase of sprinting
Asymmetrical production of force
T/F The maximal velocity phase has shorter GCT’s compared to the acceleration phase
True
T/F Power is the true indication of maximal explosive performance
False, power does not truly indicate maximal explosive performance
What are better indicators for maximal explosive performance compared to power?
- force
- RFD
- Impulse
What should be considered during change-of-direction and agility maneuvers as a practical implication?
The production of braking forces over certain periods of time (braking impulse)
What are the 3 neurophysiological basis’ for speed
- Nervous system
- Stretch-Shortening Cycle (SSC)
- Spring-mass Model
What does strength training enhance?
Neural drive
What is an enhanced neural drive related to?
Increases in both muscular force production & the rate of force production
What does plyometric training increase
The excitability of high-threshold motor units, which increases neural drive
What could strength training and plyometric training contribute to if taken together
Increases in RFD & impulse generation
What do acute effects of SSC actions tend to increase?
Mechanical efficiency & impulse via elastic energy recovery
What are the chronic effects of SSC actions
Upregulated muscle stiffness & enhances neuromuscular activation
What should trainings aimed to improve SSC performance involve?
- Skillful, multi-joint movements that transmit forces through the kinetic chain & exploit elastic-reflexive mechanisms
What should trainings aimed to improve SSC performance be structured around?
Brief work bouts or clusters separated by frequent rest pauses to manage fatigue & emphasize work quality & technique
Which type of muscle contraction has the highest amount of muscle destruction?
Eccentric
The spring mass model is a ______ model that depicts _______ as a type of human _______ in which the displacement of body mass is the ____________ from energy produced and is delivered through the ________ _________ & extension of spring-like actions within muscle architecture
mathematical; sprinting; locomotion; aftereffect; collective coiling;
In the simple spring-mass model relative to GRF during stance phase of a sprint what is the leg represented as?
A spring
In the simple spring-mass model relative to GRF during stance phase of a sprint what is the initial stance represented as?
An uncompressed spring
In the simple spring-mass model relative to GRF during stance phase of a sprint what is the midstance represented as?
A compressed spring
In which phase do elite sprinters tend to deviate form a classic SSM?
The maximal-velocity phase
How do elite sprinters deviate from the classic SSM?
By producing much of their vertical force in the 1st half of a ground contact.
Do elite or non-elite sprinters have a more symmetrical vertical force curve?
Non-elite sprinters
What should S&C professionals emphasize the prescription of for sprinting?
Exercises that have been shown to increase neural drive while overloading musculature of the hip and knee regions involved in the SSC
What is the equivalent of a plant phase in a COD movement in sprinting?
Stance phase
The plant phase in a COD movement represents what?
The transition between deceleration & acceleration steps
What two things are critical to performance in COD & agility movements?
- Body positioning
- Maintenance of strong trunk positions
What is the GCT length for sprinting max-velocity phase
0.09 to 0.11 s
What is the GCT length for sprinting acceleration phase?
0.17 to 0.20 s
What is the GCT length for Agility
0.23 to 0.25 s
What is the GCT length for COD
0.44 to 0.72 s
The perceptual-cognitive demands on athletes are related to their abilities in what areas?
- visual search scanning
- anticipation
- decision making
- reaction time
- tactical situation
What is sprinting a series of and what is it known as?
A series of coupled flight & support phases known as strides
T/F Sprinting is described as rapid, unpaced maximal-effort running of 20s or less
False, it is 15s or less
What is sprinting classically defined based on?
The relationship between stride length & stride frequency
Stride length at max velocity Elite vs novice male sprinters
Elite: 2.70
Novice: 2.56 m
Stride frequency elite vs novice male sprinters
Elite: 4.63 steps/s
Novice: 4.43 steps/s
Running velocity elite vs novice male sprinters
Elite: 12.55 m/s
Novice: 11.25 m/s
Ground contact time at max velocity elite vs novice male sprinters
Elite: 0.087s
Novice: 0.101 s
Time spent at air maximum velocity elite vs novice male sprinters
Elite > Novice
What is sprint speed determined by
By an athlete’s stride length & stride rate
T/F more successful sprinters tend to have longer stride lengths
True
What are the 2 primary limiting factors influencing sprint performance?
RFD and proper biomechanics
What are the 3 series of subtasks of linear sprinting?
- start
- acceleration
- maximum velocity
What are the two phases of linear sprinting subtasks
- Flight phase
- Stance phase
What is the recovery segment of the swing leg
Flight phase
What is the ground preparation of the swing leg
Flight phase
During which phase does the eccentric braking period occur
Stance phase
When does the concentric propulsive period occur?
Stance phase
