What is the term referring to the synergistic action of muscle groups to produce movement around a joint?

The answer is the force –couple, this is a group of muscles that moves around the joint and this move to produce movement. A couple involves of two parallel forces that are equal in magnitude, opposite in sense and do not share a line of action. This is a pure moment and single force acting at a single point. 

yes it is   dangerous

explanation:

because that foot is discusting and could get you sick

what are the options