PPT 4 + 5 - Program Design and Technique for Speed and Agility (Ch19) Flashcards
Difference between change of direction and agility.
Change of Direction:
The skills & abilities needed to explosively change movement direction, velocities, or modes.
Agility:
The skills & abilities needed to change direction, velocity, or mode in response to a stimulus. Requires use of perceptual-cognitive ability.
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.
To execute movement techniques, athletes must apply
F=ma
During most athletic activities, there is a limited amount of time available to produce
force
2 Variables That Describe Force Relative to the Time Available to Produce Force
Rate of Force Development (RFD)
Impulse
What is the rate of force development?
is the development of maximal force in minimal time.
(used as an index of explosive strength) ; index of explosive strength.
Change in force divided by time.
For RFD, is force applied briefly or for aa prolonged time?
briefly often 0.1-.2 seconds
Impulse
is the change in momentum resulting from a force, where momentum = mass x velocity.
is measured as the area under the force-time curve.
How should the athlete want to adjust the force time curve to improve
force time curve up and to the left, generating greater impulse and momentum during the limited time offer over which force is applied.
How should an athlete attempt to increase speed?
apply force to running surface over period of time
Changes in impulse result in changes in the
athlete’s momentum & therefore the ability to either accelerate or decelerate.
Power
Is considered a mechanical construct that does not truly indicate maximal explosive performance.
Is power indicative of explosive performance?
no, values do not provide insight into explosive performance that is fully useful to professionals because they can be affected by changes in force or velocity.
What are 3 indicators of maximal explosive performance?
direct measures include force, RFD and impulse
Which is an important factor for sprinting success?
rate of force production and impulse
What is the braking impulse?
something that should be considered during change of direction and agility maneuvers.
it is the production of braking forces over certain periods of time.
Research has shown that the combination of strength, plyometric, & sprint training produces several adaptations within the _______________________________ that may contribute to improved __________ performance.
neuromuscular, sprint
Strength training enhances…
neural drive
Enhanced strength training neural drive means
increases in both muscular force production & the rate of force production.
How does plyo increase neural drive?
increases the excitability of high-threshold motor units, which increases neural drive.
Increase in neural drive
may contribute to increases in RFD & impulse generation.
What is SSC?
is an eccentric–concentric coupling phenomenon in which muscle–tendon complexes are rapidly & forcibly lengthened, or stretch loaded, and immediately shortened in a reactive or elastic manner.
is a preparatory countermovement involving spring-like actions at the beginning of many functional tasks.
actions are particularly prevalent in sports involving running, jumping, & other explosive changes in velocity.
Acute Effects of SSC Actions
Tend to increase mechanical efficiency & impulse via elastic energy recovery.
Chronic Effects of SSC Actions
Upregulate muscle stiffness & enhance neuromuscular activation.
Training activities aimed at improving SSC performance should.. (2)
1) involve skillful, multijoint movements that transmit forces through the kinetic chain & exploit elastic-reflexive mechanisms.
2) be structured around brief work bouts or clusters separated by frequent rest pauses to manage fatigue & emphasize work quality & technique.
Spring-Mass Model
is a mathematical model that depicts sprinting as a type of human locomotion in which the displacement of a body mass is the aftereffect from energy produced & is delivered through the collective coiling & extension of spring-like actions within muscle architecture.
Initial stance: uncompressed
Midstance: compressed spring
Spring Mass Model vs Elite sprinters
tend to deviate from a classic SMM during the maximal-velocity phase by producing much of their vertical force in the 1st half of a ground contact.
Spring Mass Model vs Non-Elite sprinters
display stance phases:
that are described by the SMM.
with more symmetrical vertical force curves.
What should be main focus of prescribing exercise to elite runners?
the prescription of exercises that have been shown to increase neural drive while overloading musculature of the hip & knee regions involved in the SSC.
Plant Phase
termed stance phase in sprinting.
is the point in a C-O-D movement
that represents the transition
between the deceleration &
acceleration steps.
Effective breaking
Neuromuscular development with respect to high-velocity & high-force eccentric contractions.
2 Reasons
Motor unit recruitment pathways called upon: eccentric contraction ≠ concentric contraction.
Eccentric training adaptations appear to be specific to the eccentric loading velocity.
The perceptual-cognitive demands on athletes are related to their abilities in the areas of:
Visual search scanning, Anticipation, Decision making, Reaction time, & Tactical situation.
Sprinting
is a series of coupled flight & support phases, known as strides, orchestrated in an attempt to displace the athlete’s body down the track at maximal acceleration or velocity, usually for brief distances.
has been described as rapid, unpaced, maximal-effort running of 15 s or less.
is classically defined based on the relationship between stride length & stride frequency.
Elite Male Sprinters vs Novice Male Sprinters: Results of stride length, stride frequency and running velocity, ground contact time, time spent in air and directed vertical force.
stride length less in elite, stride frequency more in elite, running velocity is more in elite.
less ground contact time for elite, more time spent in air, and better directed vertical force.
Why do elite have better directed vertical force that novice?
an optimized knee height at maximal flexion of the recovering leg.
What is sprint speed determined by?
is determined by an athlete’s stride length & stride rate.
More successful sprinters tend to have (shorter/longer) stride lengths as a result of properly directed forces into the ground.
longer
What are 2 limiting factors during sprint performance?
RFD & proper biomechanics are 2 of the primary limiting factors influencing sprint performance.
Phases of the Linear Sprinting Subtasks (2)
I. Flight Phase
Recovery segment of the swing leg
Ground preparation of the swing leg
II. Stance (Support) Phase
Eccentric braking period
Concentric propulsive period
Overarching goal of sprinting is what
To achieve optimal stride length & stride frequency through the correct application of force.
Transmission of high forces
must occur within a (short/long) stance phase (ground contact time).
short
Fundamental Training Objectives to Enhance Performance & Prevent Injury During the Development of Speed in Practical Settings:
1) Emphasize brief ground support times as a means of achieving rapid stride rate.
- Requires high levels of explosive strength
- Consistent exposure to speed training
- Properly designed strength training program
2) Emphasize the further development of the SSC as a means to increase the amplitude of impulse for each step of the sprint.
Shallow cutting angles is above or below 75 degrees?
below
Aggressive cutting angles is above or below 75 degrees?
above