plyometrics Flashcards
plyometric exercise refers to activitesthat enable a muscle to reach
maximal force in the shortest possible time
what is the stretch-shortening cycle (SSC)
a rapid lengthening movement (eccentric) is quickly followed by a shortening movement (concentric)
what are the 3 elements of muscular performance
endurance
strength
power
waht is the greatest measurable force taht is exereted by a muscle or muscle group to overcome resistance during a single maximum effort
strength
power is related to the strength and speed of movement and is defined as the work produced by a muscle per unit of time.
what are the work/power equations?
work = force x distance
power = work/time
plyometric training is an exercise modality especially effective in developing ___________
power
plyometric exercise refers to activities that enable a muscle to reach __________ force in the _____________ possible time
maximal, shortest
what sets plyometrics apart from power
a rapid lengthening movement (eccentric) is quickly followed by a shortening movement (concetnric)
parallel elastic component
non contractile is made up of what?
epimysium
perimysium
endomysium
sarcolemma
what provides resistance when a muscle is passively stretched?
PEC (parallel elastric component)
what is located near teh musculotendinous junction?
mechanoreceptor
what is mechanoreceptors of golgi tendon organ senstive to?
increases is muscular tension
what causes a muscle to reflexively relax when stimulated?
golgi tendon organ (GTO)
- GTO inhibits force production
protects against over contraction or too much tension
a muscle spindle is a proprioceptor located in intrafusal muscle fibers and monitors? which results in?
changes in muscle length which results in muscle contraction
*muscle contraction during rapid stretching (stretch reflex)
what interacts with one another to ultimately produce force output during plyometric exercise?
SEC, PEC, CC (biomechanical model), Muscle Spindles, motor unit recruitment, and golgi tendon organ (neurophysiological model)
phases of plyometric: eccentric
during eccentric contractions, the load on the muscle is ____________ than the force developed by the ________ ______________-
greater
muscle itself
variables to the eccentric phase
manipulation of what 3 things will ahve a significant effect on the energy stored during the phase
- magnitude of stretch
- rate of stretch (quick/slow)
- duration of stretch
the brief isometric phase between the eccentric pre stretch and concentric force production is called
amortization
programming: dosage considerations
plyometric (speed/strength)
sets
reps
rest
load/intensity
frequency
adapted from Davies et. al article
sets: 3-5
reps: 3-8 reps
rest: 2-3 min
load/intensity: light load (20-30% 1 RM)/high effort
frequency: 2x/week (48-72 hours)
phases of plyometric
phase 1 eccentric:
action
physiological event
**action: **stretch of the agonist muscle
**PE: **elastic energy is stored in the series elastic component. muscle spindles are stimulated
phases of plyometric
phase 2- amortization
action:
physiological event:
action: pauses between phases 1 and 3
PE: type Ia afferent nerve synapse with alpha motor neurons. alpha motor neurons transmit signals to agonist muscle group
phases of a plyometric
phase III - concentric
action: shortening of agonist muscle fibers
PE: elasticenergy is released from teh series elastic component. alpha motor neurons stimulate the agonist muscle group
what are the 3 phases of the strethc shortening cycle
- eccentric
- amortizaiton
- concentric
what does PEC mean?
parallel elastric component
what does SEC mean?
the SEC is the workhorse of plyometrics
series elastic component
waht does CC mean?
contractile component
what are the 6 components to function?
- muscle performance
- cardiopulmonary/endurance
- mobility/felxibility
- neuromuscualr control/coordination
- stability
- balance/postural equilibrium
