Glossary of Terms Flashcards
What is Plyometrics?
- method in which an eccentric muscle contraction is suddenly terminated in an explosive isometric contraction
- thereby producing a powerful myotatic reflex
- a sharp extension of the passive components of the muscle complex and a subsequent explosive concentric component.
What is Power?
the performance of work per unit time.
• Power is strength that is applied over a distance for a specific amount of time.
• Speed depends on coordination, efficiency of movement and timing.
What is an Agonist Muscle?
These are the muscles that are acting as the prime movers.
They produce the most significant contribution to the movement.
The assistant movers play a more secondary role in assisting the prime action.
What are Synergist muscles?
These are the muscles that actively provide an additive contribution to the agonist muscle during a muscle contraction.
(i.e. The gluteus maximus acts synergistically to counteract the hip flexion action of rectus femoris as it extends the knee when risng from a low squat)
What are Stabilizer muscles?
These are the muscles that stabilize/support the body segment statically or dynamically while the other muscles carry out a movement involving other joints.
• During static stabilization the muscles contract either isometrically or very slowly.
• During dynamic stabilization the muscle are in continuous contraction while simultaneously carrying out a mobilizing role.
What are Neutralizer muscles?
These are the muscles that counteract the unwanted actions of other muscles by tending to produce opposite movements.
What are Tonic muscles?
- These are the postural or antigravity muscles that offer stability and resist gravity.
- These muscles are usually penniform, contain a higher proportion of ST muscle fibers, generally cross only one joint, lie deeper below the surface and perform extensor actions including abduction and external rotation.
What are Phasic muscles?
- These are the muscles that provide movement.
- These muscles are usually more superficial, contain more fast twitch fibres, often cross more than one joint and perform flexor functions, including adduction and medial rotation.
What is the Length Tension Relationship?
- this is the amount of potential force (tension) that a muscle can exert related to its length.
- The number of myosin crossbridge heads that can align with active sites on an actin filament at any given time in the sarcomere is dependent on the relative length (percentage of contraction) of the muscle.
Describe a Sarcomere
Is the distance between two Z lines: the smallest contractile unit of skeletal muscle.
Describe the Sarcoplasm
The muscle fiber’s aqueous protoplasm that contains enzymes, lipids, glycogen, nuclei, mitochondria and organelles.
What is the Sarcolemma
- This is the thin elastic membrane composed of a plasma membrane and a basement membrane that encloses the muscle fiber’s cellular contents.
- The plasma membrane conducts the electrochemical wave of depolarization.
Describe the Endomysium
The fine layer of areolar connective tissue that encircles each muscle fiber and is continuous with the sarcolemma.
It separates one muscle fiber from its neighboring fibers.
What is the Perimysium?
A collagenous sheath of connective tissue which surrounds a bundle of up to 150 muscle fibers referred to as a fasciculus.
Describe the Epimysium
- The course overcoat of dense fibrous connective tissue that surrounds the entire muscle belly.
- It is tapered at its distal end as it blends into and joins the intramuscular sheathes and deep fascia that form the dense connective tissue of the tendons.
