Power Development

Question 1

where do plyometrics sit on the force-velo spectrum/

Answer 1

between power and speed, speed-strength
*power can’t be plyos but plyos can be power

Question 2

define power

Answer 2

the ability to do work in a short period of time; high rate of force development; speed-strength

Question 3

define static power

Answer 3

the ability to produce power from a static position

Question 4

define power-endurance

Answer 4

the ability to maintain power over a prolonged period

Question 5

define reactive power

Answer 5

the ability to produce power during a stretch-shortening cycle

Question 6

what are some examples of static power?*

Answer 6

• sitting to bench and jumping
• spring from sprint block
• starting block for swim
• football lineman

Question 7

what are some examples of reactive power?*

Answer 7

• jumping in volleyball
• countermovement jump

Question 8

what are some examples of power-endurance?

Answer 8

• hockey player, constrant single leg power
• sprinting
• pitcher
• dragon boat

Question 9

list the calculations for power

Answer 9

power = force x distance/time = work/time = force x velocity

power = strength x speed

Question 10

at which time is power defined on a force x velocity graph?

Answer 10

200 ms/250 ms (mid point between maximum strength/force and max time)

Question 11

what did the curves look like on the force x velocity graph of untrained bs heavy resistance trained vs explosive-ballistic-trained

Answer 11

untrained: lowest trajectory, moving with lower force

heavy res. training: goes up witg higher trajectory and has highest max force at the end

exp. ballistic: has highest force at the beginning, then end up between the other 2 for max strength

Question 12

define impulse

Answer 12

• change in momentum
• product of force and time
  goal = increase RFD (rate of force development)

Question 13

define power

Answer 13

• rate of doing work, measured as the product of force and velocity
• high power outputs are required to rapidly accelerate, decelerate, or achieve high velocities
• max force exerted in the least amount of time
• big pop, little time

Question 14

we can achieve the same amount of power in _

Answer 14

different ways
- key difference is impulse (rate at which force is produced)

Question 15

What models describe how power is produced?

Answer 15

mechanical model
- SEC (series elastic component) & PEC (parallel elastic component)
*tendinous and muscular responses

neurophysiological model
- potentiation through SSC (stretch shortening cycle)(stretch reflex)
*muscle brain connection

Question 16

describe the mechanical model

Answer 16

elastic energy in musculotendinous units areincreased with a rapid stretch (eccentric muscle action) and then briefly stored
- if a concentric muscle action follows immediately, the stored energy is released, contributing to the total force production - if not it is released as heat

Question 17

describe the components in the mechanical model

Answer 17

• the series elastic component (SEC), when stretched, stores elastic energy that increases the force produced
• the contractile component (CC) (ie. actin, myosin, cross-bridges) is the primary source of muscle force during concentric muscle action
• the parallel elastic component (PEC) (ie. epimysium, perimysium, endomysium, sarcolemma) exerts a passive force with unstimulated muscle stretch

Question 18

what example did dylan show in class to demonstrate the mechanical model?

Answer 18

middle finger stretch
- the only that changes was the speed at which you pulled and let go

Question 19

the neurophysiological model involves _

Answer 19

potentiation (changes in the force-velocity characteristics of the muscle’s contractile components caused by stretch) of the concentric muscle action by use of the stretch reflex

Question 20

describe the neurophysiological model

Answer 20

• model uses potentiation
• stretch reflex is the body’s involuntary response to an external stimulus that stretches muscles
• when muscle spindles are stimulated, the stretch reflex is stimulated, sending input to the spinal cord via type 1a afferent nerve fibers
• after synapsing with the alpha motor neurons in the spinal cord, impulses travel to the agonist extrafusal fibers, causing a reflexive muscle action
• dampens GTOP inhibition (spindles faster than GTO response)

Question 21

when can the neurophysiological model fail?

Answer 21

usually because there is too much stretch going on
- can’t overcome reflex, body shuts off
- body’s protective mechanism

Question 22

describe the stretch reflex based on the diagram shown in class

Answer 22

when muscle spindles are stimulated, the stretch reflex is stimulated, sending input to the spinal cord via type 1a nerve fibers
- after synapsing with the alpha motor neurons in the spinal cord, impulses travel to the agonism extrafusal fibers, causing a reflexive muscle action

Question 23

what are the 3 phases of the SSC?

Answer 23

eccentric, amortization, concentric

Question 24

describe the SSC

Answer 24

• the stretch-shortening cycle (SSC) employs both the energy storage of the SEC (mechanical) and sdtimulation of the stretch reflex (neurophysiological) to facilitate maximal increase in muscle recruitment over a minimal amount of time
• a fast rate of musculotendinous stretch is vital to muscle recruitment and activity resulting from the SSC

Question 25

describe the action and physiological event of the eccentric phase

Answer 25

action: stretch of the agonist muscle
physiological: elastic energy is stored in the series elastic component. Muscle spindles are stimulated

Question 26

describe the action and physiological event of the amortization phase

Answer 26

action: pause between phases I & III

physiological: type Ia afferent nerves synapse with alpha motor neurons. Alpha motor neurons transmit signals to agonist muscle group

Question 27

describe the action and physiological event of the concentric phase

Answer 27

action: shortening of agonist muscle fibers

physiological event: elastic energy is released from the series elastic component. Alpha motor neurons stimulate the agonist muscle group

Question 28

describe the SSC in terms of a long jump

Answer 28

• eccentric phase begins at touchdown and continues until the movement ends
• the amortization phase is the transition from eccentric to concentric phases, it is quick and without movement
• the concentric phase follows the amortization phase and comprises the entire push-off tine, until the athlete’s foot leaves the surface

Question 29

describe power categorization in terms of jumps

Answer 29

jumps>
knee, hip or ankle>
multi resp/ single resp>
bi-lateral or unilateral>
plane of motion

Question 30

what 4 plyo movement categories do we program?

Answer 30

• single response single plane
• single response multi plane
• multi response single plane
• multi response multi plane