Power Development Flashcards
where do plyometrics sit on the force-velo spectrum/
between power and speed, speed-strength
*power can’t be plyos but plyos can be power
define power
the ability to do work in a short period of time; high rate of force development; speed-strength
define static power
the ability to produce power from a static position
define power-endurance
the ability to maintain power over a prolonged period
define reactive power
the ability to produce power during a stretch-shortening cycle
what are some examples of static power?*
- sitting to bench and jumping
- spring from sprint block
- starting block for swim
- football lineman
what are some examples of reactive power?*
- jumping in volleyball
- countermovement jump
what are some examples of power-endurance?
- hockey player, constrant single leg power
- sprinting
- pitcher
- dragon boat
list the calculations for power
power = force x distance/time = work/time = force x velocity
power = strength x speed
at which time is power defined on a force x velocity graph?
200 ms/250 ms (mid point between maximum strength/force and max time)
what did the curves look like on the force x velocity graph of untrained bs heavy resistance trained vs explosive-ballistic-trained
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
define impulse
- change in momentum
- product of force and time
goal = increase RFD (rate of force development)
define power
- 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
we can achieve the same amount of power in _
different ways
- key difference is impulse (rate at which force is produced)
What models describe how power is produced?
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
describe the mechanical model
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
describe the components in the mechanical model
- 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
what example did dylan show in class to demonstrate the mechanical model?
middle finger stretch
- the only that changes was the speed at which you pulled and let go
the neurophysiological model involves _
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
describe the neurophysiological model
- 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)
when can the neurophysiological model fail?
usually because there is too much stretch going on
- can’t overcome reflex, body shuts off
- body’s protective mechanism
describe the stretch reflex based on the diagram shown in class
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
what are the 3 phases of the SSC?
eccentric, amortization, concentric
describe the SSC
- 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
describe the action and physiological event of the eccentric phase
action: stretch of the agonist muscle
physiological: elastic energy is stored in the series elastic component. Muscle spindles are stimulated
describe the action and physiological event of the amortization phase
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
describe the action and physiological event of the concentric phase
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
describe the SSC in terms of a long jump
- 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
describe power categorization in terms of jumps
jumps>
knee, hip or ankle>
multi resp/ single resp>
bi-lateral or unilateral>
plane of motion
what 4 plyo movement categories do we program?
- single response single plane
- single response multi plane
- multi response single plane
- multi response multi plane
