plyometric and speed- unit 4 Flashcards
what is phase 1 of SSC?
eccentric. stretch of the agonist muscle. elastic energy is stored. muscle spindles stimulated. signal sent to spinal cord. an example is dipping down before a big jump.
what is phase 2 of SSC?
the amortization phase, pause between phase 1 and 3.the nerve synapse meets the spinal cord. signal is send to the muscle. it is also called the isometric transition between eccentric and concentric- trying to reverse direction.
what is phase 3 of SSC?
the concentric phase. shortening of the agonist muscles. elastic energy is released from the SEC, stretched muscle is stimulated by the nerve. an example is the propulsion upward in a jump. the “stored” energy.
what do muscle spindles do?
react to the rate of change of the length.
what is the SSC?
stretch shortening cycle. it explains the energy storing capabilities of the series elastic component (SEC) and the stimulation of the stretch reflex (myotactic) that brings in maximal muscle recruitment over a shirt period of time.
what are series elastic components or SEC?
elastic structures in series with the contractile component that can store energy like a spring after being stretched forceably. primarily the tendon but also involves muscle. the actin and myosin stores the energy
what is a plyometric exercise?
a quick, powerful movement after a prestretch (counter movement) - this counter movement is eccentric, and involves the SSC. the purpose is to use the stretch reflex as a natural elastic component of a muscle. and tendon to increase power.
what is speed?
the ability to achieve a high velocity. it involves several components: exploitation of the SSC (every foot step), development of force via increased muscle force production (think bulky sprinters), technique (if high level track sprinter technique important), stride frequency and legth (this defines speed, these are the 2 factors that go into it)
what are the 2 components of the stretch shortening cycle?
mechanical and neurophysiological
what is mechanical SSC?
as the SEC lengthens, elastic energy stored, if concentric comes right after eccentric, the stored energy released with high force, if the transition (amortization) is too long, the energy is lost as heat
what is neurophysiological SSC?
involves potentiation of the concentric muscle action by use of the stretch reflex. muscle spindles are sensitive to magnitude and rate of stretch. a quick stretch of high magnitude results in reflective muscle action. if the concentric action does not immediately follow the stretch the ability goes away.
what is the purpose of plyometric exercise?
used to develop explosiveness, starting speed, power and joint stiffness, high magnitude, short duration eccentric loading possible (eccentric braking as well), age, experience, and training level should be considered before doing so. as well as history, goals, and testing results.
what parts of the body does plyometric focus on?
typically involve the lower body for athletic movement and power development, can also do upper body.
who began plyo and what did it used to be called?
russia in 1960 Tur Verkhashansky, used to be called the depth jump- off one box and onto another. the word was coined by a USA track athlete (fred wilk), when he saw other teams doing this to warm up.
what type of movements does plyo involve?
jumping or throwing movements that result in “release”. exploitation of SSC leads to increased force production in concentric. animals do this when they dip down before they jump.
