What do the synergistic do?

Answer 1

When muscles contract to perform movements they usually have a primary purpose for a specific function (e.g. Biceps Brachii primarily performs elbow flexion). In more complex muscle groups (usually around joints) the muscles doing most of the work are called prime movers. In order to provide stability and somewhat of a backup in case a muscle fatigues there are secondary muscles that have a specific function...in addition to assisting other muscles in their functions. these muscle are called secondary movers or synergistic muscles. This describes the relationship between muscles that perform (in part) the same function. So muscle A and Muscle B do the same thing - they are synergistic muscles. the opposite would be termed antagonistic muscles (e.g. Biceps bends the arm - triceps straightens the arm) they work against each other to provide control in multiple directions

This is a muscle which works with an agonist and antagonist muscle to create movement. Synergist muscles help stabilise muscle movements to keep them even and they control the movement to help keep the range of motion safe and desired. An example of a pair of synergist muscles is when the brachioradialis and the bicep work together to flex or extend the arm by moving the elbow joint.