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Tying roles of muscles all together

Muscles with multiple agonist actions attempt to perform all of their actions when contracting cannont determine which actions are appropriate for the task at hand
PERFORMED actions depend on several factors: Motor units activated joint position muscle length relative contraction or relaxation of other muscles acting on the joint
Two synergist muscles may counteract their opposing actions to accomplish a common task
Example of two synergist muscles counteracting opposing actions Kicking a ball: Agonist muscles are primarily responsible for hip & knee flex/ext. Hamstrings are antagonistic and relax to allow kick Preciseness of kick depends on the involvement of many other muscles...
Continued... Lower extremity route and subsequent angle at the point of contact depend upon a certain amount of relative contraction or relaxation in hip abductors, adductors, internal rotators, external rotators (acting in synergistic fash to for preciseness
Continued... Synergistic muscles in contralateral hip and pelvic area must be under relative T to help fixate or stabilize the pelvis on that side to provide a relatively stable base for the hip Ex: Pectineus & Tensor Fascia Latae are add/abd in addition to flexors
Continued... Abduction and Adduction neutralize each other Common action of the two muscles results in hip flexion (by the hip flexors which are stablized because of the latter discussed)
Antagonistic muscles produce Actions opposite to those of the antogonist: Elbow extensors--Elbow flexors Elbow mvmnt in returning to hanging position after chinning is extension, but triceps and anconeus are not being contracted. Elbow flexors contract conc. followed by ecc.
Specific exercise are needed for Each antagonistic muscle group
Reversal of Muscle Function A muscle group described to perform a given function can contract to control the exact opposite motion.
When a particular muscle contracts it tend to pull both of its ends towards the gaster. If neither of the bones to which a muscle is attached are stabilized then the two bones move toward each other upon contraction. More common: one bone is more stable and less stable bone moves toward it
Created by: jmgibson1